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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

For the fiscal year ended December 31, 2009

OR

for the transition period from                     to                     

Commission File No. 0-14710

XOMA Ltd.

(Exact name of registrant as specified in its charter)

Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ¨    No  x

Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act.    Yes  ¨    No  x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  ¨    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K    ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a smaller reporting company. See definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Large Accelerated Filer  ¨    Accelerated Filer  x    Non-Accelerated filer  ¨    Smaller reporting company  ¨

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act of 1934).    Yes  ¨    No  x

The aggregate market value of voting shares held by non-affiliates of the registrant is $134,644,609 as of June 30, 2009

Number of Common Shares outstanding as of March 9, 2010: 261,191,984

DOCUMENTS INCORPORATED BY REFERENCE:

Portions of the Company’s Proxy Statement for the Company’s 2010 Annual General Meeting of Shareholders are incorporated by reference into Part III of this Report.

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XOMA Ltd.

2009 FORM 10-K ANNUAL REPORT

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PART I

Overview

XOMA Ltd. (“XOMA”), a Bermuda company, is a biopharmaceutical company focused on the discovery, development and manufacture of therapeutic antibodies designed to treat inflammatory, autoimmune, infectious and oncological diseases. Our proprietary development pipeline includes XOMA 052, an anti-interleukin-1 beta (“IL-1 beta”) antibody, XOMA 3AB, a biodefense anti-botulism antibody candidate, and preclinical antibody discovery programs in several indications. We have a fully integrated product development platform, extending from preclinical science to development and manufacturing. We have multiple revenue streams resulting from the licensing of antibody technologies, biodefense contracts and discovery and development collaborations and product royalties. Our technologies have contributed to the success of marketed antibody products, including LUCENTIS^® (ranibizumab injection) for wet age-related macular degeneration and CIMZIA^® (certolizumab pegol) for rheumatoid arthritis and Crohn’s disease.

We have established on-going technology licensing programs for certain of our proprietary technologies, which have attracted numerous significant licensees including Bayer Heathcare AG, Johnson & Johnson (formerly Centocor, Inc.), Merck & Co., Inc. (“Merck”), Pfizer Inc. (“Pfizer”) and Takeda Pharmaceutical Company Limited (“Takeda”). We have a premier antibody discovery and development platform that includes multiple antibody discovery or phage display libraries that increase our ability and that of our partners to discover new therapeutic antibodies. Once an antibody is discovered, we use a number of proprietary technologies including our Human Engineering™, affinity maturation, bacterial cell expression and manufacturing technologies to enhance and improve the qualities of the antibodies for efficacy, safety, stability, productivity and cost. Some of XOMA’s technologies are used widely across the industry and have generated significant revenues for the company. For example, bacterial cell expression technology is a key biotechnology for the discovery and manufacture of antibodies and other proteins. Thus far, more than 50 pharmaceutical and biotechnology companies have signed bacterial cell expression licenses with us, and a number of licensed product candidates are in clinical development.

Our biodefense initiatives currently include a $65 million multiple-year contract funded by the National Institute of Allergy and Infectious Diseases (“NIAID”), a part of the National Institutes of Health (“NIH”), to support our ongoing development of drug candidates toward clinical trials in the treatment of botulism poisoning. XOMA also develops products with premier pharmaceutical companies including Novartis AG (“Novartis”), Schering-Plough Research Institute, a division of Schering Corporation, now a subsidiary of Merck (referred to herein as “Merck/Schering-Plough”) and Takeda.

Strategy

We are advancing a pipeline of biologic products using our proven expertise, technologies and capabilities from antibody discovery through product development. We seek to expand our pipeline by developing proprietary products and technologies, providing contract services to government agencies responsible for biodefense and entering into licensing and collaborative arrangements with pharmaceutical and biotechnology companies. The principal elements of our strategy are to:

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Proprietary Products

As part of our strategy, we are focusing our technology and resources on advancing our emerging proprietary pipeline. Below is a summary of our proprietary products:

In the fourth quarter of 2009, we announced the initiation of our Phase 2 clinical program for XOMA 052 in Type 2 diabetes, Type 1 diabetes and cardiovascular disease. The clinical trials are designed to further evaluate the use of multiple dose regimens on the safety, pharmacodynamics and efficacy of XOMA 052 in cardiometabolic and other diseases, and based on positive results, select doses for pivotal Phase 3 studies. In February of 2010, we announced that enrollment had begun in a 325-patient Phase 2 dose-ranging clinical trial of XOMA 052 in Type 2 diabetes patients. The initiation of the Phase 2 clinical program follows the announcement in July of 2009 of positive results from the U.S. Phase 1 trial, which continued to demonstrate that XOMA 052 is well tolerated in patients. Further XOMA 052 showed clinically meaningful reductions in glycosylated hemoglobin, fasting blood glucose, high sensitivity C-reactive protein and erythrocyte sedimentation rate, a standard biomarker of systemic inflammation and cardiovascular risk. Generally, a more consistent response was seen across patients in a multiple dose regimen compared to the single dose regimens. Pharmacokinetic results continue to support monthly or less frequent dosing.

We developed XOMA 052 using our proprietary antibody technologies, capabilities and expertise. XOMA owns worldwide rights to the antibody and related intellectual property.

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XOMA 3AB is in the pre-Investigational New Drug (“IND”) stage, currently in nonclinical studies to assess safety through funding provided by NIAID. We have a history of successfully providing contract services to the U.S. government for the development of anti-botulinum neurotoxin antibodies.

Partnership Products

XOMA partners with world-class organizations in research and development of new antibody products. Below is a list of activities in 2009 through such collaborations:

Royalties and Technology Licenses

Royalties

XOMA earns low-single digit royalties on sales of CIMZIA^® (certolizumab pegol) in the U.S. and Canada from UCB Celltech, a branch of UCB S.A. (“UCB”). Royalties earned from these sales were $0.5 million in 2009 and $0.1 in 2008. CIMZIA^®, an anti-tumor necrosis factor product, was approved by the U.S. Food and Drug Administration (“FDA”) in April of 2008 for the treatment of moderate-to-severe Crohn’s disease in adults who have not responded to conventional therapies. In addition, CIMZIA^® was approved for the treatment of moderate-to-severe rheumatoid arthritis in adults by the FDA in May of 2009 and in Canada in September of 2009. UCB is responsible for the marketing and sales effort in support of this product. According to UCB, worldwide net sales of CIMZIA^® were approximately $104.6 million during 2009.

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XOMA earned mid- and low-single digit royalties on the following marketed antibody products in 2009:

Technology Licenses

Below is a summary of certain proprietary technologies owned by us and available for licensing to other companies:

In 2009, we recognized $42.3 million in revenue related to the licensing of our antibody discovery technologies. In February of 2009, we expanded our existing collaboration with Takeda to provide Takeda with access to multiple antibody discovery technologies for a $29 million expansion fee, before taxes and other costs. In addition, in the second half of 2009, we entered into antibody discovery collaborations with Arana Therapeutics Limited, a wholly-owned subsidiary of Cephalon, Inc. (“Arana”), and The Chemo-Sero-Therapeutic Research Institute, a Japanese research foundation known as Kaketsuken, involving multiple proprietary XOMA antibody research and development technologies for fees of $6 million and $8 million, respectively. We may be entitled to future milestone payments and royalties on product sales related to the antibody discovery collaborations.

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We have granted over 50 licenses to biotechnology and pharmaceutical companies to use our patented and proprietary technologies relating to bacterial expression of recombinant pharmaceutical products. Bacterial antibody expression is also a key technology used in multiple systems for high-throughput screening of antibody domains. Expression of antibodies by phage display technology, for example, depends upon the expression and secretion of antibody domains from bacteria as properly folded, functional proteins.

Many licensees of our bacterial cell expression technology have developed, or are in the process of developing, antibodies for which we may be entitled to future milestone payments and royalties on product sales. Under the terms of our license agreement with Pfizer, signed in 2007, we received an up-front cash payment of $30 million and from 2008 through 2009 we received four milestone payments relating to four undisclosed product candidates, including a payment of $0.5 million for the initiation of a Phase 3 clinical trial. We are also eligible for additional milestone, royalty and other fees on future sales of all products subject to this license.

Current licensees include but are not limited to the following companies:

These licenses are sometimes associated with broader agreements which may include expanded license rights, cell line development and process development.

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We also have access to certain intellectual property rights and services that augment our existing integrated antibody technology platform and development capabilities and further compress product development timelines. This broad antibody technology platform and expertise is available for building our antibody product pipeline as well as those of our collaborators.

Proprietary Product Summary:

The following table describes important information related to the proprietary products we are currently developing:

Partnership Product Summary:

The following table describes important information related to certain products that we are currently developing or have developed in the past, for which we may earn royalties on product sales in the future:

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Licensed Product Summary:

The following table describes important information related to certain products developed under licenses with us, for which we earn or may earn royalties on product sales in the future:

Financial and Legal Arrangements of Product Collaborations, Licensing and Other Arrangements

Current Agreements

Takeda

In November of 2006, we entered into a fully funded collaboration agreement with Takeda for therapeutic monoclonal antibody discovery and development. Under the agreement, we will discover and optimize therapeutic antibodies against multiple targets selected by Takeda. Takeda will make up-front, annual maintenance and milestone payments to us, fund our research and development and manufacturing activities for preclinical and early clinical studies and pay royalties on sales of products resulting from the collaboration. Takeda will be responsible for clinical trials and commercialization of drugs after an IND submission and is granted the right to manufacture once a product enters into Phase 2 clinical trials. In the fourth quarter of 2009, certain discovery and development programs under this collaboration were discontinued following analysis of the research data. This resulted in the recognition of $2.8 million of the remaining unamortized balance in deferred revenue pertaining to the discontinued programs.

In February of 2009 we expanded our existing collaboration to provide Takeda with access to multiple antibody technologies, including a suite of research and development technologies and integrated information and data management systems. We received a $29 million expansion fee, of which $23.2 million was received in cash in February of 2009 and the remainder was withheld for payment to the Japanese taxing authority. After deducting $0.9 million in costs incurred through the third quarter of 2009 related to the agreement, we recognized $28.1 million in revenue in 2009. We may receive potential milestones and royalties on sales of antibody products in the future.

Arana

In September of 2009, we entered into an antibody discovery collaboration with Arana, a wholly-owned subsidiary of Cephalon, Inc., involving multiple proprietary XOMA antibody research and development technologies, including a new antibody phage display library and a suite of integrated information and data

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management systems. Arana agreed to pay us a fee of $6 million, and we may be entitled to future milestone payments, aggregating up to $3 million per product, and royalties on product sales.

Kaketsuken

In October of 2009, we entered into an antibody discovery collaboration with Kaketsuken, a Japanese research foundation, involving multiple proprietary XOMA antibody research and development technologies, including a new antibody phage display library and a suite of integrated information and data management systems. Kaketsuken agreed to pay us a fee of $8 million, and we may be entitled to future milestone payments, aggregating up to $0.2 million per product, and royalties on product sales.

NIAID

In March of 2005, we were awarded a $15 million competitive bid contract from NIAID to develop three anti-botulinum neurotoxin monoclonal antibodies. Under this contract, we created production cell lines using our proprietary antibody expression systems, built Master and Manufacturer’s Working Cell Banks, developed production processes and produced initial quantities of the three antibodies. The contract was performed over an 18-month period and was fully funded with federal funds from NIAID under Contract No. HHSN266200500004C. Final acceptance of the project was received in October of 2006.

In July of 2006, we were awarded a $16.3 million contract funded with federal funds from NIAID under Contract No. HHSN266200600008C/N01-Al-60008 to produce monoclonal antibodies for the treatment of botulism to protect United States citizens against the harmful effects of botulinum neurotoxins used in bioterrorism. Under this contract, we have created and produced an innovative injectable product comprised of three anti-type A botulinum neurotoxin monoclonal antibodies to support entry into Phase 1 human clinical trials. This work was substantially complete as of December 31, 2009.

In September of 2008, we were awarded a third contract for $65 million funded with federal funds from NIAID under Contract No. HHSN272200800028C to continue development of our anti-botulinum antibody product candidates, including XOMA 3AB and additional product candidates. As part of the contract, we will develop, evaluate and produce the clinical supplies to support an IND filing with the FDA and conduct preclinical studies required to support human clinical trials.

SRI International

In the third quarter of 2009, we began work on two biodefense subcontract awards from SRI International, including a $1.7 million award to develop novel antibody drugs against the virus that causes severe acute respiratory syndrome and a $2.2 million award to develop a novel antibody, known as F10, that has been shown to neutralize group 1 influenza A viruses, including the H1N1 and H5N1 strains. The subcontract awards are funded through NIAID.

Novartis

In November of 2008, we restructured our product development collaboration with Novartis, which involves six development programs including the HCD122 program. HCD122, which is a fully human anti-CD40 antagonist antibody intended as a treatment for B-cell mediated diseases, including malignancies and autoimmune diseases, is currently recruiting patients for a Phase 1/2 lymphoma trial. The antibody has a dual mechanism of action that involves inhibition of CD40-ligand mediated growth and survival while recruiting immune effector cells to kill CD40-expressing tumor cells through a process known as antibody-dependent cellular cytotoxicity (ADCC). CD40, a member of the tumor necrosis factor, or TNF, family of antigens, is a cell surface antigen expressed in B-cell malignancies and involved in a broad variety of immune and inflammatory responses.

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Under the restructured agreement, Novartis made a payment to us of $6.2 million in cash; reduced our existing debt by $7.5 million; will fully fund all future research and development expenses; may pay potential milestones of up to $14 million and double-digit royalty rates for two ongoing product programs, including HCD122; and has provided us with options to develop or receive royalties on four additional programs. In exchange, Novartis has control over the HCD122 program and the additional ongoing program, as well as the right to expand the development of these programs into additional indications outside of oncology. As part of the agreement, Novartis paid us for all project costs incurred after July 1, 2008.

The collaboration between XOMA and Novartis (then Chiron Corporation) began in 2004 with the signing of an exclusive, worldwide, multi-product agreement to develop and commercialize multiple antibody products for the treatment of cancer. We shared expenses and revenue, generally on a 70-30 basis, with our share being 30 percent. Financial terms included initial payments to us in 2004 totaling $10 million and a note agreement, secured by our interest in the collaboration, to fund up to 75 percent of our share of expenses beginning in 2005. The secured note agreement with Novartis, which was executed in May of 2005, is due and payable in full in June of 2015. At December 31, 2009, the outstanding principal balance under this note agreement totaled $13.3 million and, pursuant to the terms of the arrangement as restructured in November of 2008, we will not make any additional borrowings on the Novartis note. In the first quarter of 2007, the mutual obligations of XOMA and Novartis to work together on an exclusive basis in oncology expired, except with respect to existing collaborative product development projects.

In December of 2008, we entered into a Manufacturing and Technology Transfer Agreement with Novartis, effective July 1, 2008. Under this agreement, XOMA was engaged by Novartis to perform research and development, process development, manufacturing and technology transfer activities with respect to the ongoing product programs now controlled by Novartis under the restructured product development collaboration. The work performed by XOMA under this agreement, which was fully funded by Novartis, was completed in the third quarter of 2009.

Merck/Schering-Plough

In May of 2006, we entered into a fully funded collaboration agreement with Merck/Schering-Plough for therapeutic monoclonal antibody discovery and development. Under the agreement, Merck/Schering-Plough will make up-front, annual maintenance and milestone payments to us, fund our research and development activities related to the agreement and pay royalties on sales of products resulting from the collaboration. During the collaboration, we will discover therapeutic antibodies against multiple targets selected by Merck/Schering-Plough using multiple human antibody phage display libraries, may optimize antibodies through affinity maturation or other protein engineering, may use our proprietary Human Engineering™ technology to humanize antibody candidates generated by hybridoma techniques, perform preclinical studies to support regulatory filings, develop cell lines and production processes and produce antibodies for initial clinical trials. Merck/Schering-Plough selected the first target at the inception of the agreement and, in December of 2006, exercised its right to initiate the additional discovery and development programs.

In the second quarter of 2009, we successfully completed the agreed-upon activities of certain programs under the collaboration and transferred these programs to Merck/Schering-Plough for continued development. As a result, the number of discovery and development programs under this collaboration was reduced. This resulted in the recognition of $2.6 million in May of 2009 of the remaining unamortized balance in deferred revenue pertaining to these transferred programs.

Merck/Schering-Plough/AVEO Pharmaceuticals, Inc. (“AVEO”)

In April of 2006, we entered into an agreement with AVEO to utilize our Human Engineering™ technology to humanize AV-299, AVEO’s novel anti-HGF antibody, under which AVEO paid us an up-front license fee and

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development milestones. In addition, we will receive royalties on sales of products resulting from the agreement. Under this agreement we created four Human Engineering™ versions of the original AV-299, all of which met design goals and from which AVEO selected one as its lead development candidate. In September of 2006, as a result of the successful humanization of AV-299, we entered into a second agreement with AVEO to manufacture and supply AV-299 in support of early clinical trials. Under the agreement, we created AV-299 production cell lines, conducted process and assay development, and performed Good Manufacturing Practices (“cGMP”) manufacturing activities. AVEO retains all development and commercialization rights to AV-299 and may be required to pay XOMA annual maintenance fees, additional development milestones and royalties in the future.

In April of 2007, Merck/Schering-Plough entered into a research, development and license agreement with AVEO concerning AV-299 and other anti-HGF molecules. In connection with the aforementioned license agreement, AVEO has assigned its entire right, title and interest in, to and under its manufacturing agreement with XOMA to Merck/Schering-Plough. Revenue related to this contract declined in 2009 as a result of our nearing the end of the contracted service arrangement.

UCB

Celltech Therapeutics Ltd., now UCB Celltech, a branch of UCB, utilized our bacterial cell expression technology under license in the development of CIMZIA^® for the treatment of moderate-to-severe Crohn’s disease in adults who have not responded to conventional therapies and for the treatment of moderate-to-severe rheumatoid arthritis in adults. We are entitled to receive a low-single digit royalty on sales of CIMZIA^® in countries where our bacterial cell expression technology is patented, which includes the U.S. and Canada. CIMZIA^® was approved by the FDA in April of 2008 for the treatment of Crohn’s disease and in May of 2009 for the treatment of rheumatoid arthritis. CIMZIA^® was approved in Canada for the treatment of moderate-to-severe rheumatoid arthritis in adults in September of 2009.

Genentech

In April of 1996, we entered into a collaboration agreement with Genentech for the development of RAPTIVA^®. In March of 2003, we entered into amended agreements which called for us to share in the development costs and called for Genentech to finance our share of development costs via a convertible subordinated loan. Under the loan agreement, upon FDA approval of the product, which occurred in October of 2003, we elected to pay $29.6 million of the development loan in convertible preference shares, which are convertible into approximately 3.8 million common shares at a price of $7.75 per common share.

In January of 2005, we restructured our arrangement with Genentech on RAPTIVA^® under which we were entitled to receive mid-single digit royalties on worldwide sales of RAPTIVA^® in all indications. The previous cost and profit sharing arrangement for RAPTIVA^® in the U.S. was discontinued and Genentech was responsible for all operating and development costs associated with the product. In the first half of 2009, RAPTIVA^® was withdrawn from the commercial drug markets and royalties ceased.

Genentech utilized our bacterial cell expression technology under license in the development of LUCENTIS^® for the treatment of neovascular wet age-related macular degeneration. LUCENTIS^® was approved by the FDA in June of 2006 and in the European Union in January of 2007. We were entitled to receive a low-single digit royalty on worldwide sales of LUCENTIS^®. In the third quarter of 2009, we sold our LUCENTIS^® royalty interest to Genentech for $25 million, including royalty revenue from the second quarter of 2009. We will not receive any further royalties from sales of LUCENTIS^®.

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Equity Agreements

In May of 2009, we entered into a definitive agreement with an institutional investor to sell 11,764,706 units, with each unit consisting of one of our common shares and a warrant to purchase 0.50 of a common share, for gross proceeds of approximately $10 million, before deducting placement agent fees and estimated offering expenses of $0.8 million, in a registered direct offering. The investor purchased the units at a price of $0.85 per unit. The warrants, which represent the right to acquire an aggregate of up to 5,882,353 common shares, were exercisable at any time on or after May 15, 2009 and prior to May 20, 2014 at an exercise price of $1.02 per share. As of December 31, 2009, all warrants issued in May of 2009 remained outstanding. Refer to Item 7: Management’s Discussion and Analysis of Financial Condition and Results of Operations: Subsequent Events for disclosure regarding certain amendments made to the terms of the warrants issued in May of 2009 and the number of shares issued upon exercise of these warrants subsequent to the end of 2009.

In June of 2009, we entered into a definitive agreement with certain institutional investors to sell 10,434,782 units, with each unit consisting of one of our common shares and a warrant to purchase 0.50 of a common share, for gross proceeds of approximately $12 million, before deducting placement agent fees and estimated offering expenses of $0.8 million, in a second registered direct offering. The investor purchased the units at a price of $1.15 per unit. The warrants, which represent the right to acquire an aggregate of up to 5,217,391 common shares, are exercisable at any time on or prior to December 10, 2014 at an exercise price of $1.30 per share. As of December 31, 2009, all warrants issued in June of 2009 remained outstanding. Refer to Item 7: Management’s Discussion and Analysis of Financial Condition and Results of Operations: Subsequent Events for disclosure regarding certain amendments made to the terms of the warrants issued in June of 2009 subsequent to the end of 2009.

In the third quarter of 2009, we entered into an At Market Issuance Sales Agreement (the “ATM Agreement”), with Wm Smith & Co. (“Wm Smith”), under which we may sell up to 25 million of our common shares from time to time through Wm Smith, as the agent for the offer and sale of the common shares. Wm Smith may sell these common shares by any method permitted by law deemed to be an “at the market” offering as defined in Rule 415 of the Securities Act of 1933, including but not limited to sales made directly on The NASDAQ Global Market, on any other existing trading market for the common shares or to or through a market maker. Wm Smith may also sell the common shares in privately negotiated transactions, subject to our approval. We pay Wm Smith a commission equal to 3% of the gross proceeds of all common shares sold through it as sales agent under the ATM Agreement but in no event less than $0.02 per share. Shares sold under the ATM Agreement are sold pursuant to a prospectus which forms a part of a registration statement declared effective by the Securities and Exchange Commission on May 29, 2008. From the inception of the ATM Agreement through December 31, 2009, we sold a total of 4,050,617 common shares under this agreement for aggregate gross proceeds of $2.9 million. Refer to Item 7: Management’s Discussion and Analysis of Financial Condition and Results of Operations: Subsequent Events for disclosure regarding the number common shares sold under this agreement subsequent to the end of 2009.

Recently Terminated Agreements

Goldman Sachs Term Loan

In September of 2009, we fully repaid our term loan facility with Goldman Sachs, which was a five-year term loan facility originally entered into in November of 2006 and refinanced in May of 2008. As previously disclosed, we were not in compliance with the requirements of the relevant provisions of this loan facility, due to the cessation of royalties from sales of RAPTIVA^®. Repayment of this loan facility discharged all of our obligations to the lenders.

We repaid the outstanding principal balance of $42 million, accrued interest to the date of payment of $2.4 million and a prepayment premium of $2.5 million. In the third quarter of 2009, we recorded a loss on repayment of debt of $3.6 million, which included the prepayment premium and the recognition of unamortized debt issuance costs of $1.1 million.

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Equity Line of Credit

In October of 2008, we entered into a common share purchase agreement (the “Purchase Agreement”) with Azimuth Opportunity Ltd. (“Azimuth”), pursuant to which we obtained a committed equity line of credit facility (the “Facility”) under which we could sell up to $60 million of our registered common shares to Azimuth over a 24-month period, subject to certain conditions and limitations. Shares under the Facility were sold pursuant to a prospectus which forms a part of a registration statement declared effective by the Securities and Exchange Commission on May 29, 2008. At the end of the third quarter of 2009, the Facility was no longer in effect, and no additional shares can be issued thereunder. From the inception of the Facility through 2009, we sold a total of 42,228,428 common shares to Azimuth for aggregate gross proceeds of $33.9 million. This included the sale of 34.3 million shares in two transactions in September of 2009 that Azimuth agreed to purchase notwithstanding that the purchase prices were below the minimum price of $1.00 required by the Purchase Agreement. We negotiated a discount rate (excluding placement agent fees) of 8.0% for those transactions. Prior to the successful conclusion of negotiations, Azimuth was not obligated to purchase these shares. Offering expenses incurred in 2009 related to sales to Azimuth were $0.4 million.

Research and Development

Our research and development expenses currently include costs of personnel, supplies, facilities and equipment, consultants, third party costs and other expenses related to preclinical and clinical testing. In 2009, our research and development expenses were $58.1 million compared with $82.6 million in 2008 and $66.2 million in 2007.

Our research and development activities can be divided into those related to our internal projects and those related to collaborative and contract arrangements, which are reimbursed by our customers. In 2009, research and development expenses related to internal projects were $42.2 million compared with $58.5 million in 2008 and $45.8 million in 2007. In 2009, research and development expenses related to collaborative and contract arrangements were $15.9 million compared with $24.1 million in 2008 and $20.4 million in 2007. Refer to Item 7: Management’s Discussion and Analysis of Financial Condition and Results of Operations—Research and Development Expenses for further information regarding our research and development expenses.

Competition

The biotechnology and pharmaceutical industries are subject to continuous and substantial technological change. Competition in the areas of recombinant DNA-based and antibody-based technologies is intense and expected to increase as new technologies emerge and established biotechnology firms and large chemical and pharmaceutical companies continue to advance in the field. A number of these large pharmaceutical and chemical companies have enhanced their capabilities by entering into arrangements with or acquiring biotechnology companies or entering into business combinations with other large pharmaceutical companies. Many of these companies have significantly greater financial resources, larger research and development and marketing staffs and larger production facilities than ours. Moreover, certain of these companies have extensive experience in undertaking preclinical testing and human clinical trials. These factors may enable other companies to develop products and processes competitive with or superior to ours. In addition, a significant amount of research in biotechnology is being carried out in universities and other non-profit research organizations. These entities are becoming increasingly interested in the commercial value of their work and may become more aggressive in seeking patent protection and licensing arrangements. Furthermore, many companies and universities tend not to announce or disclose important discoveries or development programs until their patent position is secure or, for other reasons, later. As a result, we may not be able to track development of competitive products, particularly at the early stages. There can be no assurance that developments by others will not render our products or technologies obsolete or uncompetitive.

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Without limiting the foregoing, we are aware of the following competitors for the products and candidates shown in the table below. This table is not intended to be representative of all existing competitors in the market:

Regulatory

Our products are subject to comprehensive preclinical and clinical testing requirements and to approval processes by the FDA and by similar authorities in other countries. Our products are primarily regulated on a product-by-product basis under the United States Food, Drug and Cosmetic Act and Section 351(a) of the Public Health Service Act. Most of our human therapeutic products are or will be classified as biologic products. Approval of a biologic for commercialization requires licensure of the product and the manufacturing facilities. The review of therapeutic biologic products is carried out by the FDA’s Center for Drug Evaluation and Research, the body that also reviews drug products.

The FDA regulatory process is carried out in several phases. Prior to beginning human clinical testing of a proposed new biologic product, an IND is filed with the FDA. This document contains scientific information on the proposed product, including results of testing of the product in animal and laboratory models. Also included is information on manufacturing the product and studies on toxicity in animals and a clinical protocol outlining the initial investigation in humans.

The initial stage of clinical testing, Phase 1, ordinarily encompasses safety, pharmacokinetic and pharmacodynamic evaluations. Phase 2 testing encompasses investigation in specific disease states designed to provide preliminary efficacy data and additional information on safety. Phase 3 studies are designed to further establish clinical safety and efficacy and to provide information allowing proper labeling of the product following approval. Phase 3 studies are most commonly multi-center, randomized, placebo-controlled trials in which rigorous statistical methodology is applied to clinical results. Other designs may also be appropriate in specific circumstances.

Following completion of clinical trials, a BLA is submitted to the FDA to request marketing approval. Internal FDA committees are formed that evaluate the application, including scientific background information, animal and laboratory efficacy studies, toxicology, manufacturing facility and clinical data. During the review process, a dialogue between the FDA and the applicant is established in which FDA questions are raised and additional information is submitted. During the final stages of the approval process, the FDA generally requests presentation of clinical or other data before an FDA advisory committee, at which point, some or all of such data may become available. Also, during the later stages of review, the FDA conducts an inspection of the manufacturing facility to establish that the product is made in conformity with good manufacturing practice. If all outstanding issues are satisfactorily resolved and labeling established, the FDA issues a license for the product and for the manufacturing facility, thereby authorizing commercial distribution.

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The FDA has substantial discretion in both the product approval process and the manufacturing approval process. It is not possible to predict at what point, or whether, the FDA will be satisfied with our submissions or whether the FDA will raise questions which may delay or preclude product approval or manufacturing facility approval. As additional clinical data is accumulated, it will be submitted to the FDA and may have a material impact on the FDA product approval process. Given that regulatory review is an interactive and continuous process, we have adopted a policy of limiting announcements and comments upon the specific details of the ongoing regulatory review of our products, subject to our obligations under the securities laws, until definitive action is taken. There can be no assurance any of the products we have under development will be developed successfully, obtain the requisite regulatory approval or be successfully manufactured or marketed.

In Europe, most of our human therapeutic products are or will be classified as biological medicinal products which are assessed through a centralized procedure by the European Medicines Agency (“EMEA”). The EMEA coordinates the evaluation and supervision of medicinal products throughout the European Union and the European Economic Area. The assessment of the Marketing Authorization Application (“MA”) is carried out by a Rapporteur and a Co-Rapporteur appointed by the Committee for Medicinal Products for Human Use (“CHMP”), which is the expert scientific committee of the EMEA.

The Rapporteur and Co-Rapporteur are drawn from the CHMP membership representing member states of the European Union. In addition to their responsibility for undertaking scientific assessments of an application for a MA, the Rapporteur and the Co-Rapporteur liaise with the applicant on behalf of the CHMP in an effort to provide answers to queries raised by the CHMP. Their assessment report(s) is circulated to and considered by the full CHMP membership, leading to the production ultimately of a CHMP opinion which is transmitted to the applicant and the European Commission. The final decision on the grant of a MA is made by the European Commission as the licensing authority of the European Community (“Community”). Under Community law, a positive decision issued by the European Commission represents the grant of a MA. Such an authorization allows a medicinal product to be placed on the European market. Upon the grant of an MA in the European Union, certain member states require pricing approval before the product can be placed into commercial distribution.

Under Community law, the applicant may request grant of a MA under exceptional circumstances if comprehensive data on the efficacy and safety of the drug, under normal conditions of use cannot be provided because its intended indications are encountered so rarely (such as in the case of a medicinal product intended for treating an orphan disease) that comprehensive evidence cannot reasonably be collected, the present state of scientific knowledge will not allow comprehensive information to be collected, or it would be against generally accepted medical ethics to collect comprehensive information. The Rapporteur, Co-Rapporteur and the other CHMP members will assess the justification/data submitted for exceptional circumstances as part of the overall assessment of the benefit/risk of the application. It is up to the CHMP, during the review, to ultimately decide on whether grant of a MA under exceptional circumstances is justified on the evidence before them. Approval under exceptional circumstances is subject to a requirement for specific procedures related to safety and results of its use and is reviewed annually to reassess the risk-benefit balance of the product. Once approval is granted, the product can be marketed under the single European MA in all member states of the European Union and the European Economic Area. Consistent with the single MA, the labeling for Europe is identical throughout all member states except that all labeling must be translated into the local language of the country of intended importation and in relation to the content of the so called “blue box” on the outer packaging in which locally required information may be inserted.

Orphan drugs are those intended for use in rare diseases or conditions. As a result of the high cost of development and the low return on investment for rare diseases, governments provide regulatory and commercial incentives for the development of drugs for small disease populations. In the United States, the term ‘‘rare disease or condition’’ means any disease or condition which affects less than 200,000 persons in the United States. Applications for United States orphan drug status are evaluated and granted by the Office of Orphan Products Development (“OOPD”) of the FDA. In the United States, orphan drugs are subject to the standard regulatory process for marketing approval but are exempt from the payment of user fees for licensure, receive market exclusivity for a period of seven years and some tax benefits, and are eligible for OOPD grants. In

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Europe, orphan medicinal products are those intended for the diagnosis, prevention or treatment of a life-threatening or chronically debilitating condition affecting not more than five in 10,000 persons in the Community. The EMEA’s Committee for Orphan Medicinal Products (“COMP”) reviews applications seeking orphan designation. If the European Commission agrees with a positive assessment made by COMP, then the product will receive a positive designation through adoption of a decision by the European Commission. Orphan medicinal products are exempt from fees for protocol assistance and scientific advice from the Scientific Advice Working Party during development, reduction or exemption of MA and other fees, and ten-year market exclusivity upon granting of a MA in respect of the approved clinical indication. Moreover, manufacturers may be eligible for grants or other financial incentives from the Community and Member States programs.

Patents and Trade Secrets

Patent and trade secret protection is important to our business and our future will depend in part on our ability to obtain patents, maintain trade secret protection and operate without infringing on the proprietary rights of others. As a result of our ongoing activities, we hold and have filed applications for a number of patents in the United States and internationally to protect our products and important processes. We also have obtained or have the right to obtain exclusive licenses to certain patents and applications filed by others. However, the patent position of biotechnology companies generally is highly uncertain and no consistent policy regarding the breadth of allowed claims has emerged from the actions of the U.S. Patent and Trademark Office (“Patent Office”) with respect to biotechnology patents. Accordingly, no assurance can be given that our patents will afford protection against competitors with similar technologies, or others will not obtain patents claiming aspects similar to those covered by our patent applications.

We have established a portfolio of patents related to our bacterial expression technology, including claims to novel promoter sequences, secretion signal sequences, compositions, methods for expression and secretion of recombinant proteins from bacteria, including immunoglobulin gene products, and improved methods and cells for expression of recombinant protein products. U.S. Patent Nos. 5,576,195 and 5,846,818 are related to DNA encoding a pectate lyase signal sequence, recombinant vectors, host cells and methods for production and externalization of recombinant proteins. U.S. Patent Nos. 5,595,898, 5,698,435 and 5,618,920 address secretable immunoglobulin chains, DNA encoding the chains and methods for their recombinant production. U.S. Patent Nos. 5,693,493, 5,698,417 and 6,204,023 relate to methods for recombinant production/secretion of functional immunoglobulin molecules. U.S. Patent Nos. 7,094,579 and 7,396,661 relate to eukaryotic signal sequences and their use in methods for prokaryotic expression of recombinant proteins. U.S. Patent No. 6,803,210 relates to improved bacterial host cells that are deficient in one or more of the active transport systems for an inducer of an inducible promoter, such as arabinose for an araB promoter, and methods for the use of such cells for the production of recombinant proteins. Most of the more important European patents in this portfolio expired in July of 2008 or earlier.

We have also established a portfolio of patent applications related to our mammalian expression technology, including U.S. Patent No. 7,192,737, related to methods for increasing the expression of recombinant polypeptides using expression vectors containing multiple copies of a transcription unit encoding a polypeptide of interest.

We have established a portfolio of patents and applications related to our Human Engineering™ technology, including U.S. Patent No. 5,766,886, directed to methods of modifying antibody variable domains to reduce immunogenicity. Related patents and applications are directed to antibodies engineered according to our patented methods. We believe that our patented Human Engineering™ technology provides an attractive alternative to other humanization technologies.

We also have issued patents in the U.S. and Europe covering XOMA 052. In May and September of 2009, the U.S. Patent and Trademark Office issued U.S. Patents 7,531,166 and 7,582,742, respectively, covering XOMA 052 and other antibodies and antibody fragments with similar binding properties for IL-1 beta, as well as nucleic acids, expression vectors and production cell lines for the manufacture of such antibodies and antibody

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fragments. The patents provide exclusivity in the U.S. into 2027 and 2026, respectively. In November of 2009, the European Patent Office granted a patent covering XOMA 052, as well as nucleic acids, expression vectors and production cell lines for the manufacture of XOMA 052. The patent provides exclusivity in Europe into 2026.

If certain patents issued to others are upheld or if certain patent applications filed by others issue and are upheld, we may require certain licenses from others in order to develop and commercialize certain potential products incorporating our technology. There can be no assurance that such licenses, if required, will be available on acceptable terms.

Where appropriate, we also rely on trade secrets to protect aspects of our technology. However, trade secrets are difficult to protect. We protect our proprietary technology and processes, in part, by confidentiality agreements with our employees, consultants and collaborators. These parties may breach these agreements, and we may not have adequate remedies for any breach. Our trade secrets may otherwise become known or be independently discovered by competitors. To the extent that we or our consultants or collaborators use intellectual property owned by others, we may have disputes with our collaborators or consultants or other third parties as to the rights in related or resulting know-how and inventions.

International Operations

We believe that, because the pharmaceutical industry is global in nature, international activities will be a significant part of our future business activities and that, when and if we are able to generate income, a substantial portion of that income will be derived from product sales and other activities outside the United States.

A number of risks are inherent in international operations. Foreign regulatory agencies often establish standards different from those in the United States. An inability to obtain foreign regulatory approvals on a timely basis could have an adverse effect on our international business, financial condition and results of operations. International operations may be limited or disrupted by the imposition of government controls, export license requirements, political or economic instability, trade restrictions, changes in tariffs, restrictions on repatriating profits, taxation or difficulties in staffing and managing international operations. In addition, our business, financial condition and results of operations may be adversely affected by fluctuations in currency exchange rates. There can be no assurance that we will be able to successfully operate in any foreign market.

Financial information regarding the geographic areas in which we operate is included in Note 13 to the Financial Statements: Concentration of Risk, Segment and Geographic Information.

Concentration of Risk

In 2009, Takeda and Genentech each provided more than 10% of our total revenue, neither of which represents a related party to XOMA. These key customers accounted for 65% of our total revenue in 2009 but were not responsible for any of the accounts receivable balance at December 31, 2009. NIAID, Arana and Kaketsuken accounted for 90% of the accounts receivable balance at December 31, 2009. The loss of one or more of these customers could have a material adverse effect on our business and financial condition.

In 2008, Genentech, Novartis and Merck/Schering-Plough each provided more than 10% of our total revenue, none of which represents a related party to XOMA. These key customers accounted for 81% of our total revenue in 2008 and represented 64% of the accounts receivable balance at December 31, 2008. NIAID accounted for an additional 28% of the accounts receivable balance at December 31, 2008. In 2007, Pfizer, Genentech, Merck/Schering-Plough and NIAID each provided more than 10% of our total revenue, none of which represent a related party to XOMA.

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Organization

We were incorporated in Delaware in 1981 and became a Bermuda company effective December 31, 1998, when we completed a shareholder-approved corporate reorganization, changing our legal domicile from Delaware to Bermuda and our name to XOMA Ltd. When referring to a time or period before December 31, 1998, or when the context so requires, the terms “Company” and “XOMA” refer to XOMA Corporation, a Delaware corporation and the predecessor of XOMA Ltd.

Employees

As of March 9, 2010, we employed approximately 195 full-time employees (none of which are unionized) at our facilities, principally in Berkeley, California. Our employees are primarily engaged in clinical, process development, research and product development, and in executive, business development, finance and administrative positions. We consider our employee relations to be excellent.

Available Information

For information on XOMA’s investment prospects and risks, please contact Investor Relations and Corporate Communications at (800) 246-9662 or by sending an e-mail message to investorrelations@xoma.com. Our principal executive offices are located at 2910 Seventh Street, Berkeley, California 94710, U.S.A. Our telephone number is (510) 204-7200.

The following information can be found on our website at http://www.xoma.com or can be obtained free of charge by contacting our Investor Relations Department:

We intend to satisfy the applicable disclosure requirements regarding amendments to, or waivers from, provisions of our Code of Ethics by posting such information on our website.

The following risk factors and other information included in this annual report should be carefully considered. The risks and uncertainties described below are not the only ones we face. Additional risks and uncertainties not presently known to us also may impair our business operations. If any of the following risks occur, our business, financial condition, operating results and cash flows could be materially adversely affected.

Because our product candidates are still being developed, we will require substantial funds to continue; we cannot be certain that funds will be available and, if they are not available, we may have to take actions that could adversely affect your investment and may not be able to continue as a going concern.

While our refocused business strategy has reduced capital expenditures and other operating expenses, we will need to commit substantial funds to continue development of our product candidates and we may not be able to obtain sufficient funds on acceptable terms, or at all. If adequate funds are not available, we may have to raise additional funds in a manner that may dilute or otherwise adversely affect the rights of existing shareholders,

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curtail or cease operations, or file for bankruptcy protection in extreme circumstances. We have spent, and we expect to continue to spend, substantial funds in connection with:

We finance our operations primarily through our multiple revenue streams resulting from the licensing of our antibody technologies, discovery and development collaborations, product royalties and biodefense contracts, and sales of our common shares. In September of 2009, we sold our royalty interest in LUCENTIS^® to Genentech, Inc., a wholly-owned member of the Roche Group (referred to herein as “Genentech”) for gross proceeds of $25 million, including royalty revenue from the second quarter of 2009. These proceeds, along with other funds, were used to fully repay our loan from Goldman Sachs Specialty Lending Holdings, Inc. (“Goldman Sachs”). As a result, we no longer have a royalty interest in LUCENTIS^®. In 2008, we received $8.8 million of revenue from this royalty interest.

Based on our cash reserves and anticipated spending levels, revenue from collaborations including a XOMA 052 corporate partnership, licensing transactions or biodefense contracts and other sources of funding we believe to be available, we believe that we have sufficient cash resources to meet our anticipated net cash needs through the next twelve months. Any significant revenue shortfalls, increases in planned spending on development programs or more rapid progress of development programs than anticipated, as well as the unavailability of anticipated sources of funding, could shorten this period. If adequate funds are not available, we will be required to delay, reduce the scope of, or eliminate one or more of our product development programs and further reduce personnel-related costs. Progress or setbacks by potentially competing products may also affect our ability to raise new funding on acceptable terms. As a result, we do not know when or whether:

Cash balances and operating cash flow are influenced primarily by the timing and level of payments by our licensees and development partners, as well as by our operating costs.

Global credit and financial market conditions may reduce our ability to access capital and cash and could negatively impact the value of our current portfolio of cash equivalents or short-term investments and our ability to meet our financing objectives.

Traditionally, we have funded a large portion of our research and development expenditures through raising capital in the equity markets. Recent events, including failures and bankruptcies among large commercial and investment banks, have led to considerable declines and uncertainties in these and other capital markets and may lead to new regulatory and other restrictions that may broadly affect the nature of these markets. These circumstances could severely restrict the raising of new capital by companies such as us in the future.

Recent volatility in the financial markets has also created liquidity problems in investments previously thought to bear a minimal risk. For example, money market fund investors, including us, have in the past been unable to retrieve the full amount of funds, even in highly-rated liquid money market accounts, upon maturity. Although as of December 31, 2009, we have received the full amount of proceeds from money market fund investments, an inability to retrieve funds from money market and similar short-term investments as they mature in the future could have a material and adverse impact on our business, results of operations and cash flows.

Our cash and cash equivalents are maintained in highly liquid investments with remaining maturities of 90 days or less at the time of purchase. Our short-term investments consist primarily of readily marketable debt

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securities with remaining maturities of more than 90 days at the time of purchase. While as of the date of this filing, we are not aware of any downgrades, material losses, or other significant deterioration in the fair value of our cash equivalents or short-term investments since December 31, 2009, no assurance can be given that further deterioration in conditions of the global credit and financial markets would not negatively impact our current portfolio of cash equivalents or short-term investments or our ability to meet our financing objectives.

If the trading price of our common shares fails to comply with the continued listing requirements of The NASDAQ Global Market, we would face possible delisting, which would result in a limited public market for our common shares and make obtaining future debt or equity financing more difficult for us.

Companies listed on The NASDAQ Stock Market (“NASDAQ”) are subject to delisting for, among other things, failure to maintain a minimum closing bid price per share of $1.00 for 30 consecutive business days. The closing price per share of our common shares has been below $1.00 for all but eight days since December 9, 2008. Although NASDAQ temporarily suspended the minimum bid price requirement in response to market conditions, this suspension expired on July 31, 2009.

On September 21, 2009, we received a letter from NASDAQ indicating that for the 30 consecutive business days preceding September 15, 2009, the bid price of our common shares closed below the minimum $1.00 per share requirement pursuant to NASDAQ Listing Rule 5450(a)(1) for continued inclusion on The NASDAQ Global Market. In accordance with NASDAQ Listing Rule 5810(c)(3)(A), we have a period of 180 calendar days, or until March 15, 2010, to regain compliance with the minimum bid price requirement. We anticipate receiving a further letter from NASDAQ on or shortly after March 16, 2010 indicating that we have not regained compliance with this requirement and intend to request a hearing before a NASDAQ Listing Qualification Panel (the “Panel”), which request will stay delisting pending the Panel’s decision following the hearing. At the hearing, we intend to request continued listing based on a plan for regaining compliance. Although the Panel has authority to grant us up to an additional 180 days from the date of the forthcoming NASDAQ notice to implement our plan, there can be no assurance that the Panel will grant our request for continued listing. Furthermore, we cannot be sure that our share price will comply with the requirements for continued listing of our common shares on The NASDAQ Global Market in the future. If our common shares lose their status on The NASDAQ Global Market and we are not successful in obtaining a listing on The NASDAQ Capital Market, our common shares would likely trade in the over-the-counter market.

If our shares were to trade on the over-the-counter market, selling our common shares could be more difficult because smaller quantities of shares would likely be bought and sold, transactions could be delayed, and security analysts' coverage of us may be reduced. In addition, in the event our common shares are delisted, broker-dealers have certain regulatory burdens imposed upon them, which may discourage broker-dealers from effecting transactions in our common shares, further limiting the liquidity thereof. These factors could result in lower prices and larger spreads in the bid and ask prices for common shares.

Such delisting from The NASDAQ Global Market or future declines in our share price could also greatly impair our ability to raise additional necessary capital through equity or debt financing, and could significantly increase the ownership dilution to shareholders caused by our issuing equity in financing or other transactions. Consent under the Exchange Control Act 1972 (and its related regulations) has been obtained from the Bermuda Monetary Authority for the issue and transfer of our shares, notes and other securities to and between non-residents of Bermuda for exchange control purposes, but this consent is conditional on our shares remaining listed on an appointed stock exchange. We cannot assure you that the Bermuda Monetary Authority will give the same or a similar consent in the event our common shares are no longer listed on The NASDAQ Global Market or another appointed stock exchange. In the absence of such a general consent, specific consents of the Bermuda Monetary Authority would be required for certain issues and transfers of our shares, notes and other securities.

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Because all of our product candidates are still being developed, we have sustained losses in the past and we expect to sustain losses in the future.

We have experienced significant losses and, as of December 31, 2009, we had an accumulated deficit of $784.6 million.

For the year ended December 31, 2009, we had net income of approximately $0.6 million or $0.00 per common share (basic and diluted). For the year ended December 31, 2008, we had a net loss of approximately $45.2 million or $0.34 per common share (basic and diluted).

Our ability to achieve profitability is dependent in large part on the success of our development programs, obtaining regulatory approval for our product candidates and entering into new agreements for product development, manufacturing and commercialization, all of which are uncertain. Our ability to fund our ongoing operations is dependent on the foregoing factors and on our ability to secure additional funds. Because our product candidates are still being developed, we do not know whether we will ever achieve sustained profitability or whether cash flow from future operations will be sufficient to meet our needs.

We may issue additional equity securities and thereby materially and adversely affect the price of our common shares.

We are authorized to issue, without shareholder approval, 1,000,000 preference shares, of which 2,959 were issued and outstanding as of March 9, 2010, which may give other shareholders dividend, conversion, voting, and liquidation rights, among other rights, which may be superior to the rights of holders of our common shares. In addition, we are authorized to issue, generally without shareholder approval, up to 400,000,000 common shares, of which 203,042,194 were issued and outstanding as of December 31, 2009 and 261,191,984 were issued and outstanding as of March 9, 2010. If we issue additional equity securities, the price of our common shares may be materially and adversely affected.

As announced in the third quarter of 2009, we have entered into an At Market Issuance Sales Agreement, with Wm Smith & Co. (“Wm Smith”), under which we may sell up to 25 million of our common shares from time to time through Wm Smith, as the agent for the offer and sale of the common shares. Wm Smith may sell these common shares by any method permitted by law deemed to be an “at the market” offering as defined in Rule 415 of the Securities Act of 1933, including but not limited to sales made directly on The NASDAQ Global Market, on any other existing trading market for the common shares or to or through a market maker. Wm Smith may also sell the common shares in privately negotiated transactions, subject to our approval. From the inception of this agreement through December 31, 2009, we sold a total of 4,050,617 common shares through Wm Smith for aggregate gross proceeds of $2.9 million. Subsequent to December 31, 2009, we sold an additional 8,940,225 common shares through Wm Smith for aggregate gross proceeds of $6.4 million.

In addition, on February 2, 2010, we entered into an underwritten offering with investors to sell 42 million units, with each unit consisting of one of our common shares and a warrant to purchase 0.45 of a common share, for gross proceeds of approximately $21 million, before deducting underwriting discounts and commissions and estimated offering expenses of $1.7 million. The investors purchased the units at a price of $0.50 per unit. The warrants, which represent the right to acquire an aggregate of up to 18.9 million common shares, are exercisable beginning six months and one day after issuance and have a five-year term and an exercise price of $0.70 per share.

The financial terms of future collaborative or licensing arrangements could result in dilution of our share value.

Funding from collaboration partners and others has in the past and may in the future involve issuance by us of our shares. Because we do not currently have any such arrangements, we cannot be certain how the purchase price of such shares, the relevant market price or premium, if any, will be determined or when such determinations will be made. Any such issuance could result in dilution in the value of our issued and outstanding shares.

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Our share price may be volatile and there may not be an active trading market for our common shares.

There can be no assurance that the market price of our common shares will not decline below its present market price or that there will be an active trading market for our common shares. The market prices of biotechnology companies have been and are likely to continue to be highly volatile. Fluctuations in our operating results and general market conditions for biotechnology stocks could have a significant impact on the volatility of our common share price. We have experienced significant volatility in the price of our common shares. From January 1, 2009 through March 9, 2010, our share price has ranged from a high of $1.34 to a low of $0.37. Factors contributing to such volatility include, but are not limited to:

Our therapeutic product candidates have not received regulatory approval. If these product candidates do not receive regulatory approval, neither our third party collaborators nor we will be able to manufacture and market them.

Our product candidates, including XOMA 052 and XOMA 3AB, cannot be manufactured and marketed in the United States and other countries without required regulatory approvals. The United States government and governments of other countries extensively regulate many aspects of our product candidates, including:

In the United States, the Food and Drug Administration (“FDA”) regulates pharmaceutical products under the Federal Food, Drug, and Cosmetic Act and other laws, including, in the case of biologics, the Public Health Service Act. At the present time, we believe that most of our product candidates will be regulated by the FDA as biologics. Initiation of clinical trials requires approval by health authorities. Clinical trials involve the administration of the investigational new drug to healthy volunteers or to patients under the supervision of a qualified principal investigator. Clinical trials must be conducted in accordance with FDA and International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use Good Clinical Practices and the European Clinical Trials Directive under protocols that detail the objectives of

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the study, the parameters to be used to monitor safety and the efficacy criteria to be evaluated. Other national, foreign and local regulations may also apply. The developer of the drug must provide information relating to the characterization and controls of the product before administration to the patients participating in the clinical trials. This requires developing approved assays of the product to test before administration to the patient and during the conduct of the trial. In addition, developers of pharmaceutical products must provide periodic data regarding clinical trials to the FDA and other health authorities, and these health authorities may issue a clinical hold upon a trial if they do not believe, or cannot confirm, that the trial can be conducted without unreasonable risk to the trial participants. We cannot assure you that U.S. and foreign health authorities will not issue a clinical hold with respect to any of our clinical trials in the future.

The results of the preclinical studies and clinical testing, together with chemistry, manufacturing and controls information, are submitted to the FDA and other health authorities in the form of a new drug application for a pharmaceutical product, and in the form of a BLA for a biological product, requesting approval to commence commercial sales. In responding to a new drug application or an antibody license application, the FDA or foreign health authorities may grant marketing approvals, request additional information or further research, or deny the application if it determines that the application does not satisfy its regulatory approval criteria. Regulatory approval of a new drug application, BLA, or supplement is never guaranteed, and the approval process can take several years and is extremely expensive. The FDA and foreign health authorities have substantial discretion in the drug and biologics approval processes. Despite the time and expense incurred, failure can occur at any stage, and we could encounter problems that cause us to abandon clinical trials or to repeat or perform additional preclinical, clinical or manufacturing-related studies.

Changes in the regulatory approval policy during the development period, changes in, or the enactment of additional regulations or statutes, or changes in regulatory review for each submitted product application may cause delays in the approval or rejection of an application. State regulations may also affect our proposed products. The FDA has substantial discretion in both the product approval process and manufacturing facility approval process and, as a result of this discretion and uncertainties about outcomes of testing, we cannot predict at what point, or whether, the FDA will be satisfied with our or our collaborators’ submissions or whether the FDA will raise questions which may be material and delay or preclude product approval or manufacturing facility approval. As we accumulate additional clinical data, we will submit it to the FDA, and such data may have a material impact on the FDA product approval process.

Even once approved, a product may be subject to additional testing or significant marketing restrictions, its approval may be withdrawn or it may be voluntarily taken off the market.

Even if the FDA, the European Commission or another regulatory agency approves a product candidate for marketing, the approval may impose ongoing requirements for post-approval studies, including additional research and development and clinical trials, and the FDA, European Commission or other regulatory agency may subsequently withdraw approval based on these additional trials.

Even for approved products, the FDA, European Commission or other regulatory agency may impose significant restrictions on the indicated uses, conditions for use, labeling, advertising, promotion, marketing and/or production of such product.

Furthermore, a marketing approval of a product may be withdrawn by the FDA, the European Commission or another regulatory agency or such a product may be voluntarily withdrawn by the company marketing it based, for example, on subsequently-arising safety concerns. In February of 2009, the European Medicines Agency (“EMEA”) announced that it had recommended suspension of the marketing authorization of RAPTIVA^® in the European Union and that its Committee for Medicinal Products for Human Use (“CHMP”) had concluded that the benefits of RAPTIVA^® no longer outweigh its risks because of safety concerns, including the occurrence of progressive multifocal leukoencephalopathy (“PML”) in patients taking the medicine. In the second quarter of 2009, Genentech announced and carried out a phased voluntary withdrawal of RAPTIVA^® from the U.S. market, based on the association of RAPTIVA^® with an increased risk of PML.

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The FDA, European Commission and other agencies also may impose various civil or criminal sanctions for failure to comply with regulatory requirements, including withdrawal of product approval.

We face uncertain results of clinical trials of our potential products.

Our potential products, including XOMA 052 and XOMA 3AB, will require significant additional research and development, extensive preclinical studies and clinical trials and regulatory approval prior to any commercial sales. This process is lengthy and expensive, often taking a number of years. As clinical results are frequently susceptible to varying interpretations that may delay, limit or prevent regulatory approvals, the length of time necessary to complete clinical trials and to submit an application for marketing approval for a final decision by a regulatory authority varies significantly. As a result, it is uncertain whether:

For example, in 2003, we completed two Phase 1 trials of XOMA 629, a BPI-derived topical peptide compound targeting acne, evaluating the safety, skin irritation and pharmacokinetics. In January of 2004, we announced the initiation of Phase 2 clinical testing in patients with mild-to-moderate acne. In August of 2004, we announced the results of a Phase 2 trial with XOMA 629 gel. The results were inconclusive in terms of clinical benefit of XOMA 629 compared with vehicle gel. In 2007, after completing an internal evaluation of this program, we chose to reformulate and focus development efforts on the use of this reformulated product candidate in superficial skin infections, including impetigo and the eradication of staphylococcus aureus. In the fourth quarter of 2008, we decided to curtail all spending on XOMA 629 in response to current economic conditions and to focus our financial resources on XOMA 052.

The timing of the commencement, continuation and completion of clinical trials may be subject to significant delays relating to various causes, including scheduling conflicts with participating clinicians and clinical institutions, difficulties in identifying and enrolling patients who meet trial eligibility criteria, and shortages of available drug supply. Patient enrollment is a function of many factors, including the size of the patient population, the proximity of patients to clinical sites, the eligibility criteria for the trial, the existence of competing clinical trials and the availability of alternative or new treatments. In addition, we will conduct clinical trials in foreign countries in the future which may subject us to further delays and expenses as a result of increased drug shipment costs, additional regulatory requirements and the engagement of foreign clinical research organizations, as well as expose us to risks associated with foreign currency transactions insofar as we might desire to use U.S. dollars to make contract payments denominated in the foreign currency where the trial is being conducted.

All of our product candidates are prone to the risks of failure inherent in drug development. Preclinical studies may not yield results that would satisfactorily support the filing of an IND (or a foreign equivalent) with respect to our product candidates. Even if these applications would be or have been filed with respect to our product candidates, the results of preclinical studies do not necessarily predict the results of clinical trials. Similarly, early-stage clinical trials in healthy volunteers do not predict the results of later-stage clinical trials, including the safety and efficacy profiles of any particular product candidates. In addition, there can be no assurance that the design of our clinical trials is focused on appropriate indications, patient populations, dosing regimens or other variables which will result in obtaining the desired efficacy data to support regulatory approval to commercialize the drug. Preclinical and clinical data can be interpreted in different ways. Accordingly, FDA officials or officials from foreign regulatory authorities could interpret the data in different ways than we or our partners do which could delay, limit or prevent regulatory approval.

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Administering any of our products or potential products may produce undesirable side effects, also known as adverse effects. Toxicities and adverse effects that we have observed in preclinical studies for some compounds in a particular research and development program may occur in preclinical studies or clinical trials of other compounds from the same program. Such toxicities or adverse effects could delay or prevent the filing of an IND (or a foreign equivalent) with respect to such products or potential products or cause us to cease clinical trials with respect to any drug candidate. In clinical trials, administering any of our products or product candidates to humans may produce adverse effects. These adverse effects could interrupt, delay or halt clinical trials of our products and product candidates and could result in the FDA or other regulatory authorities denying approval of our products or product candidates for any or all targeted indications. The FDA, other regulatory authorities, our partners or we may suspend or terminate clinical trials at any time. Even if one or more of our product candidates were approved for sale, the occurrence of even a limited number of toxicities or adverse effects when used in large populations may cause the FDA to impose restrictions on, or stop, the further marketing of such drugs. Indications of potential adverse effects or toxicities which may occur in clinical trials and which we believe are not significant during the course of such clinical trials may later turn out to actually constitute serious adverse effects or toxicities when a drug has been used in large populations or for extended periods of time. Any failure or significant delay in completing preclinical studies or clinical trials for our product candidates, or in receiving and maintaining regulatory approval for the sale of any drugs resulting from our product candidates, may severely harm our reputation and business.

Given that regulatory review is an interactive and continuous process, we maintain a policy of limiting announcements and comments upon the specific details of regulatory review of our product candidates, subject to our obligations under the securities laws, until definitive action is taken.

Certain of our technologies are relatively new and are in-licensed from third parties, so our capabilities using them are unproven and subject to additional risks.

We license technologies from third parties. These technologies include but are not limited to phage display technologies licensed to us in connection with our bacterial cell expression technology licensing program. However, our experience with some of these technologies remains relatively limited and, to varying degrees, we are still dependent on the licensing parties for training and technical support for these technologies. In addition, our use of these technologies is limited by certain contractual provisions in the licenses relating to them and, although we have obtained numerous licenses, intellectual property rights in the area of phage display are particularly complex. If the owners of the patent rights underlying the technologies we license do not properly maintain or enforce those patents, our competitive position and business prospects could be harmed. Our success will depend in part on the ability of our licensors to obtain, maintain and enforce our licensed intellectual property. Our licensors may not successfully prosecute the patent applications to which we have licenses, or our licensors may fail to maintain existing patents. They may determine not to pursue litigation against other companies that are infringing these patents, or they may pursue such litigation less aggressively than we would. Our licensors may also seek to terminate our license, which could cause us to lose the right to use the licensed intellectual property and adversely affect our ability to commercialize our technologies, products or services.

To the extent our present and future revenue consist of royalties on product sales, our revenue will rely on sales of products marketed and sold by others.

We have only a royalty interest in CIMZIA^® and receive revenue from sales of CIMZIA^® in the U.S. for the treatment of moderate-to-severe Crohn’s disease and in the U.S. and Canada for the treatment of moderate-to-severe rheumatoid arthritis. CIMZIA^® was approved in the United States in April of 2008 for the treatment of Crohn’s disease. In May of 2009, CIMZIA^® was approved by the FDA for the treatment of moderate-to-severe rheumatoid arthritis in adults and in Canada in September of 2009. UCB is responsible for the marketing and sales effort in support of this product. We have no role in marketing and sales efforts, and UCB does not have an express contractual obligation to us regarding the marketing or sales of CIMZIA^®.

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Successful commercialization of CIMZIA^® is subject to a number of risks, including, but not limited to:

We do not know whether there will be, or will continue to be, a viable market for the products in which we have an ownership or royalty interest.

Although CIMZIA^® was approved in the United States in April of 2008 for the treatment of Crohn’s disease, and in the United States in May of 2009 and in Canada in September of 2009 for the treatment of rheumatoid arthritis, it may not be accepted in the marketplace. Furthermore, even if other products in which we have an interest receive approval in the future, they may not be accepted in the marketplace. In addition, we or our collaborators or licensees may experience difficulties in launching new products, many of which are novel and based on technologies that are unfamiliar to the healthcare community. We have no assurance that healthcare providers and patients will accept such products, if developed. For example, physicians and/or patients may not accept a product for a particular indication because it has been biologically derived (and not discovered and developed by more traditional means) or if no biologically derived products are currently in widespread use in that indication. Similarly, physicians may not accept a product, such as CIMZIA^®, if they believe other products to be more effective or are more comfortable prescribing other products.

Safety concerns may also arise in the course of on-going clinical trials or patient treatment as a result of adverse events or reactions. For example, in February of 2009, the EMEA announced that it had recommended suspension of the marketing authorization of RAPTIVA^® in the European Union and EMD Serono Inc., the company that marketed RAPTIVA^® in Canada (“EMD Serono”) announced that, in consultation with Health Canada, the Canadian health authority (“Health Canada”), it would suspend marketing of RAPTIVA^® in Canada. In March of 2009, Merck Serono Australia Pty Ltd, the company that marketed RAPTIVA^® in Australia (“Merck Serono Australia”), following a recommendation from the Therapeutic Goods Administration, the Australian health authority (“TGA”), announced that it was withdrawing RAPTIVA^® from the Australian market. In the second quarter of 2009, Genentech announced and carried out a phased voluntary withdrawal of RAPTIVA^® from the U.S. market, based on the association of RAPTIVA^® with an increased risk of PML. As a result, sales of RAPTIVA^® ceased in the second quarter of 2009.

Furthermore, government agencies, as well as private organizations involved in healthcare, from time to time publish guidelines or recommendations to healthcare providers and patients. Such guidelines or recommendations can be very influential and may adversely affect the usage of any products we may develop directly (for example, by recommending a decreased dosage of a product in conjunction with a concomitant therapy or a government entity withdrawing its recommendation to screen blood donations for certain viruses) or indirectly (for example, by recommending a competitive product over our product). Consequently, we do not know if physicians or patients will adopt or use our products for their approved indications.

We or our third party collaborators or licensees may not have adequate manufacturing capacity sufficient to meet market demand.

UCB is responsible for manufacturing or arranging for the manufacturing of commercial quantities of CIMZIA^®. Should UCB have difficulty in providing manufacturing capacity to produce this product in sufficient

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quantities, we do not know whether they will be able to meet market demand. If not, we will not realize revenue from the sales of this product. If any of our product candidates are approved, because we have never commercially introduced any pharmaceutical products, we do not know whether the capacity of our existing manufacturing facilities can be increased to produce sufficient quantities of our products to meet market demand. Also, if we or our third party collaborators or licensees need additional manufacturing facilities to meet market demand, we cannot predict that we will successfully obtain those facilities because we do not know whether they will be available on acceptable terms. In addition, any manufacturing facilities acquired or used to meet market demand must meet the FDA’s quality assurance guidelines.

Our agreements with third parties, many of which are significant to our business, expose us to numerous risks.

Our financial resources and our marketing experience and expertise are limited. Consequently, our ability to successfully develop products depends, to a large extent, upon securing the financial resources and/or marketing capabilities of third parties.

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Because our collaborators and licensees are independent third parties, they may be subject to different risks than we are and have significant discretion in determining the efforts and resources they will apply related to their agreements with us. If these collaborators and licensees do not successfully develop and market these products, we may not have the capabilities, resources or rights to do so on our own. We do not know whether our collaborators or licensees will successfully develop and market any of the products that are or may become the subject of one of our collaboration or licensing arrangements. In particular, each of these arrangements provides for funding solely by our collaborators or licensees. Furthermore, our contracts with NIAID contain numerous standard terms and conditions provided for in the applicable federal acquisition regulations and customary in many government contracts. Uncertainty exists as to whether we will be able to comply with these terms and conditions in a timely manner, if at all. In addition, we are uncertain as to the extent of NIAID’s demands and the flexibility that will be granted to us in meeting those demands.

Even when we have a collaborative relationship, other circumstances may prevent it from resulting in successful development of marketable products.

Although we continue to evaluate additional strategic alliances and potential partnerships, we do not know whether or when any such alliances or partnerships will be entered into.

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Products and technologies of other companies may render some or all of our products and product candidates noncompetitive or obsolete.

Developments by others may render our products, product candidates, or technologies obsolete or uncompetitive. Technologies developed and utilized by the biotechnology and pharmaceutical industries are continuously and substantially changing. Competition in the areas of genetically engineered DNA-based and antibody-based technologies is intense and expected to increase in the future as a number of established biotechnology firms and large chemical and pharmaceutical companies advance in these fields. Many of these competitors may be able to develop products and processes competitive with or superior to our own for many reasons, including that they may have:

These factors may enable others to develop products and processes competitive with or superior to our own or those of our collaborators. In addition, a significant amount of research in biotechnology is being carried out in universities and other non-profit research organizations. These entities are becoming increasingly interested in the commercial value of their work and may become more aggressive in seeking patent protection and licensing arrangements. Furthermore, many companies and universities tend not to announce or disclose important discoveries or development programs until their patent position is secure or, for other reasons, later; as a result, we may not be able to track development of competitive products, particularly at the early stages. Positive or negative developments in connection with a potentially competing product may have an adverse impact on our ability to raise additional funding on acceptable terms. For example, if another product is perceived to have a competitive advantage, or another product’s failure is perceived to increase the likelihood that our product will fail, then investors may choose not to invest in us on terms we would accept or at all.

The examples below pertain to competitive events in the market which we review quarterly and are not intended to be representative of all existing competitive events. Without limiting the foregoing, we are aware that:

XOMA 052

We have initiated clinical testing of XOMA 052, a potent anti-inflammatory monoclonal antibody targeting IL-1 beta, in Type 2 diabetes patients and cardiovascular disease patients. Other companies are developing other products based on the same or similar therapeutic targets as XOMA 052 and these products may prove more effective than XOMA 052. We are aware that:

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XOMA 3AB

CIMZIA^®

In addition to CIMZIA^®, there are four other FDA-approved anti-TNF therapies to treat moderate-to-severe rheumatoid arthritis: Amgen’s Enbrel^® (etanercept), Johnson & Johnson’s Remicade^® (infliximab) and Simponi™ (golimumab) and Abbott Laboratories’ Humira^® (adalimumab), with two of them, infliximab and adalimumab, also approved for moderate-to-severe active Crohn’s disease in adults.

Manufacturing risks and inefficiencies may adversely affect our ability to manufacture products for ourselves or others.

To the extent we continue to provide manufacturing services for our own benefit or to third parties, we are subject to manufacturing risks. Additionally, unanticipated fluctuations in customer requirements have led and may continue to lead to manufacturing inefficiencies. We must utilize our manufacturing operations in compliance with regulatory requirements, in sufficient quantities and on a timely basis, while maintaining acceptable product quality and manufacturing costs. Additional resources and changes in our manufacturing processes may be required for each new product, product modification or customer or to meet changing regulatory or third party requirements, and this work may not be successfully or efficiently completed. In

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addition, to the extent we continue to provide manufacturing services, our fixed costs, such as facility costs, would be expected to increase, as would necessary capital investment in equipment and facilities.

Manufacturing and quality problems may arise in the future to the extent we continue to perform these services for our own benefit or for third parties. Consequently, our development goals or milestones may not be achieved in a timely manner or at a commercially reasonable cost, or at all. In addition, to the extent we continue to make investments to improve our manufacturing operations, our efforts may not yield the improvements that we expect.

Because many of the companies we do business with are also in the biotechnology sector, the volatility of that sector can affect us indirectly as well as directly.

As a biotechnology company that collaborates with other biotech companies, the same factors that affect us directly can also adversely impact us indirectly by affecting the ability of our collaborators, partners and others we do business with to meet their obligations to us and reduce our ability to realize the value of the consideration provided to us by these other companies.

For example, in connection with our licensing transactions relating to our bacterial cell expression technology, we have in the past and may in the future agree to accept equity securities of the licensee in payment of license fees. The future value of these or any other shares we receive is subject both to market risks affecting our ability to realize the value of these shares and more generally to the business and other risks to which the issuer of these shares may be subject.

As we do more business internationally, we will be subject to additional political, economic and regulatory uncertainties.

We may not be able to successfully operate in any foreign market. We believe that, because the pharmaceutical industry is global in nature, international activities will be a significant part of our future business activities and that, when and if we are able to generate income, a substantial portion of that income will be derived from product sales and other activities outside the United States. Foreign regulatory agencies often establish standards different from those in the United States, and an inability to obtain foreign regulatory approvals on a timely basis could put us at a competitive disadvantage or make it uneconomical to proceed with a product or product candidate’s development. International operations and sales may be limited or disrupted by:

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If we and our partners are unable to protect our intellectual property, in particular our patent protection for our principal products, product candidates and processes, and prevent its use by third parties, our ability to compete in the market will be harmed, and we may not realize our profit potential.

We rely on patent protection, as well as a combination of copyright, trade secret, and trademark laws to protect our proprietary technology and prevent others from duplicating our products or product candidates. However, these means may afford only limited protection and may not:

Because of the length of time and the expense associated with bringing new products to the marketplace, we and our partners hold and are in the process of applying for a number of patents in the United States and abroad to protect our product candidates and important processes and also have obtained or have the right to obtain exclusive licenses to certain patents and applications filed by others. However, the mere issuance of a patent is not conclusive as to its validity or its enforceability. The United States Federal Courts or equivalent national courts or patent offices elsewhere may invalidate our patents or find them unenforceable. In addition, the laws of foreign countries may not protect our intellectual property rights effectively or to the same extent as the laws of the United States. If our intellectual property rights are not adequately protected, we may not be able to commercialize our technologies, products, or services, and our competitors could commercialize our technologies, which could result in a decrease in our sales and market share that would harm our business and operating results. Specifically, the patent position of biotechnology companies generally is highly uncertain and involves complex legal and factual questions. The legal standards governing the validity of biotechnology patents are in transition, and current defenses as to issued biotechnology patents may not be adequate in the future. Accordingly, there is uncertainty as to:

We have established an extensive portfolio of patents and applications, both United States and foreign, related to our BPI-related product candidates, including novel compositions, their manufacture, formulation, assay and use. We have also established a portfolio of patents, both United States and foreign, related to our bacterial cell expression technology, including claims to novel promoter sequences, secretion signal sequences, compositions and methods for expression and secretion of recombinant proteins from bacteria, including immunoglobulin gene products. Most of the more important European patents in our bacterial cell expression patent portfolio expired in July of 2008.

If certain patents issued to others are upheld or if certain patent applications filed by others issue and are upheld, we may require licenses from others in order to develop and commercialize certain potential products incorporating our technology or we may become involved in litigation to determine the proprietary rights of others. These licenses, if required, may not be available on acceptable terms, and any such litigation may be costly and may have other adverse effects on our business, such as inhibiting our ability to compete in the marketplace and absorbing significant management time.

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Due to the uncertainties regarding biotechnology patents, we also have relied and will continue to rely upon trade secrets, know-how and continuing technological advancement to develop and maintain our competitive position. All of our employees have signed confidentiality agreements under which they have agreed not to use or disclose any of our proprietary information. Research and development contracts and relationships between us and our scientific consultants and potential customers provide access to aspects of our know-how that are protected generally under confidentiality agreements. These confidentiality agreements may be breached or may not be enforced by a court. To the extent proprietary information is divulged to competitors or to the public generally, such disclosure may adversely affect our ability to develop or commercialize our products by giving others a competitive advantage or by undermining our patent position.

Litigation regarding intellectual property can be costly and expose us to risks of counterclaims against us.

We may be required to engage in litigation or other proceedings to protect our intellectual property. The cost to us of this litigation, even if resolved in our favor, could be substantial. Such litigation could also divert management’s attention and resources. In addition, if this litigation is resolved against us, our patents may be declared invalid, and we could be held liable for significant damages. In addition, we may be subject to a claim that we are infringing another party’s patent. If such claim is resolved against us, we or our collaborators may be enjoined from developing, manufacturing, selling or importing products, processes or services unless we obtain a license from the other party. Such license may not be available on reasonable terms, thus preventing us from using these products, processes or services and adversely affecting our revenue.

Even if we or our third party collaborators or licensees bring products to market, we may be unable to effectively price our products or obtain adequate reimbursement for sales of our products, which would prevent our products from becoming profitable.

If we or our third party collaborators or licensees succeed in bringing our product candidates to the market, they may not be considered cost-effective, and reimbursement to the patient may not be available or may not be sufficient to allow us to sell our products on a competitive basis. In both the United States and elsewhere, sales of medical products and treatments are dependent, in part, on the availability of reimbursement to the patient from third-party payors, such as government and private insurance plans. Third-party payors are increasingly challenging the prices charged for pharmaceutical products and services. Our business is affected by the efforts of government and third-party payors to contain or reduce the cost of healthcare through various means. In the United States, there have been and will continue to be a number of federal and state proposals to implement government controls on pricing. In addition, the emphasis on managed care in the United States has increased and will continue to increase the pressure on the pricing of pharmaceutical products. We cannot predict whether any legislative or regulatory proposals will be adopted or the effect these proposals or managed care efforts may have on our business.

Healthcare reform measures and other statutory or regulatory changes could adversely affect our business.

The pharmaceutical and biotechnology industries are subject to extensive regulation, and from time to time legislative bodies and governmental agencies consider changes to such regulations that could have significant impact on industry participants. For example, in light of certain highly-publicized safety issues regarding certain drugs that had received marketing approval, the U.S. Congress is considering various proposals regarding drug safety, including some which would require additional safety studies and monitoring and could make drug development more costly. We are unable to predict what additional legislation or regulation, if any, relating to safety or other aspects of drug development may be enacted in the future or what effect such legislation or regulation would have on our business.

The business and financial condition of pharmaceutical and biotechnology companies are also affected by the efforts of governments, third-party payors and others to contain or reduce the costs of healthcare to consumers. In the United States and various foreign jurisdictions there have been, and we expect that there will

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continue to be, a number of legislative and regulatory proposals aimed at changing the healthcare system, such as proposals relating to the reimportation of drugs into the U.S. from other countries (where they are then sold at a lower price) and government control of prescription drug pricing. The pendency or approval of such proposals could result in a decrease in our share price or limit our ability to raise capital or to obtain strategic collaborations or licenses.

We are exposed to an increased risk of product liability claims, and a series of related cases is currently pending against us.

The testing, marketing and sales of medical products entails an inherent risk of allegations of product liability. In the event of one or more large, unforeseen awards of damages against us, our product liability insurance may not provide adequate coverage. A significant product liability claim for which we were not covered by insurance would have to be paid from cash or other assets. To the extent we have sufficient insurance coverage, such a claim would result in higher subsequent insurance rates. In addition, product liability claims can have various other ramifications including loss of future sales opportunities, increased costs associated with replacing products, and a negative impact on our goodwill and reputation, which could also adversely affect our business and operating results.

On April 9, 2009, a complaint was filed in the Superior Court of Alameda County, California, in a lawsuit captioned Hedrick et al. v. Genentech, Inc. et al, Case No. 09-446158. The complaint asserts claims against Genentech, us and others for alleged strict liability for failure to warn, strict product liability, negligence, breach of warranty, fraudulent concealment, wrongful death and other claims based on injuries alleged to have occurred as a result of three individuals’ treatment with RAPTIVA^®. The complaint seeks unspecified compensatory and punitive damages. Since then, additional complaints have been filed in the same court, bringing the total number of pending cases to twenty-one. All of the complaints allege the same claims and seek the same types of damages based on injuries alleged to have occurred as a result of the plaintiffs’ treatment with RAPTIVA^®. Even though Genentech has agreed to indemnify us, there can be no assurance that this or other products liability lawsuits will not result in liability to us or that our insurance or contractual arrangements will provide us with adequate protection against such liabilities.

The loss of key personnel, including our Chief Executive Officer, could delay or prevent achieving our objectives.

Our research, product development and business efforts could be adversely affected by the loss of one or more key members of our scientific or management staff, particularly our executive officers: Steven B. Engle, our Chairman, Chief Executive Officer and President; Fred Kurland, our Vice President, Finance and Chief Financial Officer; Patrick J. Scannon, M.D., Ph.D., our Executive Vice President and Chief Medical Officer; and Christopher J. Margolin, our Vice President, General Counsel and Secretary. We currently have no key person insurance on any of our employees.

We may not realize the expected benefits of our initiatives to reduce costs across our operations, and we may incur significant charges or write-downs as part of these efforts.

We have pursued and may continue to pursue a number of initiatives to reduce costs across our operations. In January of 2009, we implemented a workforce reduction of approximately 42% in order to improve our cost structure. As a result, we achieved an annualized reduction in cash expenditures of approximately $27 million. We recorded charges in 2009 of $3.1 million for severance, other employee benefits and outplacement services related to the workforce reduction. In the second quarter of 2009, we vacated one of our leased buildings and recorded a restructuring charge of $0.5 million primarily related to the net present value of the net future minimum lease payments, less the estimated future sublease income.

In addition, one building remains temporarily vacant, in order to optimize our facility usage. As manufacturing demand increases in the future, we plan to resume operations at this facility. The net book value

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of fixed assets in the vacant building potentially subject to write-down is approximately $4.2 million as of December 31, 2009. Although we have determined that there was no impairment of the assets as of December 31, 2009, there can be no assurance that we will not determine otherwise as of a future date and as a consequence write down these assets as impaired.

We may not realize some or all of the expected benefits of our current and future initiatives to reduce costs. In addition to restructuring or other charges, we may experience disruptions in our operations as a result of these initiatives and write-downs.

U.S. holders of our common shares and warrants could be subject to material adverse U.S. federal income tax consequences if we were considered to be a PFIC currently or in the future.

A non-U.S. corporation generally will be a “passive foreign investment company,” or PFIC, for U.S. federal income tax purposes in any taxable year in which, after applying the relevant look-through rules with respect to the income and assets of its subsidiaries, either 75% or more of its gross income is “passive income” (generally including (without limitation) dividends, interest, annuities and certain royalties and rents not derived in the active conduct of a business) or the average value of its assets that produce passive income or are held for the production of passive income is at least 50% of the total value of its assets. In determining whether we meet the 50% test, cash is considered a passive asset and the total value of our assets generally will be treated as equal to the sum of the aggregate fair market value of our outstanding common shares plus our liabilities. If we own at least 25% (by value) of the stock of another corporation, we will be treated, for purposes of the PFIC tests, as owning our proportionate share of the other corporation’s assets and receiving our proportionate share of the other corporation’s income.

We believe that we were not a PFIC for the 2009 taxable year. However, because PFIC status is determined annually and depends on the composition of a company’s income and assets and the fair market value of its assets (including goodwill), which may be volatile in our industry, there can be no assurance that we will not be considered a PFIC for 2010 or any subsequent year. For example, taking into account our existing cash balances, if the value of our common shares were to decline materially, it is possible that we could become a PFIC in 2010 or a subsequent year. Additionally, due to the complexity of the PFIC provisions and the limited authority available to interpret such provisions, there can be no assurance that our determination regarding our PFIC status could not be successfully challenged by the Internal Revenue Service (“IRS”).

If we were found to be a PFIC for any taxable year in which a U.S. holder (as defined below) held common shares or warrants, certain adverse U.S. federal income tax consequences could apply to such U.S. holder, including a recharacterization of any capital gain recognized on a sale or other disposition of common shares or warrants as ordinary income, ineligibility for any preferential tax rate otherwise applicable to any “qualified dividend income,” a material increase in the amount of tax that such U.S. holder would owe and the possible imposition of interest charges, an imposition of tax earlier than would otherwise be imposed and additional tax form filing requirements.

For purposes of this discussion, the term “U.S. holder” means a beneficial owner of common shares or warrants that is, for U.S. federal income tax purposes, (i) an individual who is a U.S. citizen or resident, (ii) a corporation (or other entity treated as a corporation for U.S. federal income tax purposes) created or organized in or under the laws of the United States, any state thereof or the District of Columbia, (iii) an estate the income of which is includable in gross income for U.S. income tax purposes regardless of its source, or (iv) a trust, if a U.S. court is able to exercise primary supervision over the administration of the trust and one or more U.S. fiduciaries have the authority to control all substantial decisions of the trust, or if the trust has a valid election in effect under applicable U.S. Treasury Regulations to be treated as a U.S. person.

A U.S. holder owning shares in a PFIC (or a corporation that might become a PFIC) might be able to mitigate the adverse tax consequences of PFIC status by making certain elections, including “qualified electing

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fund” (a “QEF”) or “mark-to-market” elections, if deemed appropriate based on guidance provided by its tax advisor. However, it should be noted that (1) the beneficial effect of a QEF election or a mark-to-market election may be substantially diminished if such election is not made from the inception of a U.S. holder’s holding period (a “Year One Election”), (2) neither a QEF election nor a mark-to-market election can be made with respect to the warrants, (3) a Year One Election generally cannot be made for any common shares received upon exercise of the warrants (“Warrant Shares”) because the holding period of Warrant Shares is deemed, for QEF election and mark-to-market election purposes, to include the holding period of the underlying warrants but the QEF election or a mark-to-market election will not be effective until the taxable year in which the underlying warrants are exercised, and (4) a QEF election or a mark-to-market election is made on a shareholder-by-shareholder basis and, once made, can only be revoked with the consent of the IRS.

The PFIC rules are very complex, as are the requirements and effects of the various elections designed to mitigate the adverse consequences of the PFIC rules. A prospective U.S. holder should consult its own tax advisor regarding the PFIC rules, including the foregoing limitations on the ability to make a QEF election or a mark-to-market election (or to qualify either such election as a Year One Election), the timing requirements with respect to the various elections and the irrevocability of certain elections (absent the consent of the IRS).

A U.S. Holder may be required to file IRS Form 8621 if the U.S. Holder holds our common shares in any taxable year in which we are classified as a PFIC (whether or not a QEF or mark-to-market election is made).

Our ability to use our net operating loss carry-forwards and other tax attributes will be substantially limited by Section 382 of the Internal Revenue Code.

Section 382 of the Internal Revenue Code of 1986, as amended, generally limits the ability of a corporation that undergoes an “ownership change” to utilize its net operating loss carry-forwards (“NOLs”) and certain other tax attributes against any taxable income in taxable periods after the ownership change. The amount of taxable income in each taxable year after the ownership change that may be offset by pre-change NOLs and certain other pre-change tax attributes is generally equal to the product of (a) the fair market value of the corporation’s outstanding shares immediately prior to the ownership change and (b) the long-term tax exempt rate (i.e., a rate of interest established by the IRS that fluctuates from month to month). In general, an “ownership change” occurs whenever the percentage of the shares of a corporation owned, directly or indirectly, by “5-percent shareholders” (within the meaning of Section 382 of the Internal Revenue Code) increases by more than 50 percentage points over the lowest percentage of the share of such corporation owned, directly or indirectly, by such “5-percent shareholders” at any time over the preceding three years.

In 2009, we experienced an ownership change under Section 382, which subjects the amount of NOLs and other tax credit carry-forwards that can be utilized to an annual limitation, which will substantially limit the future use of our pre-change NOLs and certain other pre-change tax attributes per year.

Because we are a relatively small biopharmaceutical company with limited resources, we may not be able to attract and retain qualified personnel.

Our success in developing marketable products and achieving a competitive position will depend, in part, on our ability to attract and retain qualified scientific and management personnel, particularly in areas requiring specific technical, scientific or medical expertise. We had approximately 195 employees as of March 9, 2010. We anticipate that we will require additional experienced executive, accounting, research and development, legal, administrative and other personnel in the future. There is intense competition for the services of these personnel, especially in California. Moreover, we expect that the high cost of living in the San Francisco Bay Area, where our headquarters and manufacturing facilities are located, may impair our ability to attract and retain employees in the future. If we do not succeed in attracting new personnel and retaining and motivating existing personnel, our operations may suffer and we may be unable to implement our current initiatives or grow effectively.

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Calamities, power shortages or power interruptions at our Berkeley headquarters and manufacturing facility could disrupt our business and adversely affect our operations, and could disrupt the businesses of our customers.

Our principal operations are located in Northern California, including our corporate headquarters and manufacturing facility in Berkeley, California. In addition, many of our collaborators and licensees are located in California. All of these locations are in areas of seismic activity near active earthquake faults. Any earthquake, terrorist attack, fire, power shortage or other calamity affecting our facilities or our customers’ facilities may disrupt our business and could have material adverse effect on our business and results of operations.

We may be subject to increased risks because we are a Bermuda company.

Alleged abuses by certain companies that have changed their legal domicile from jurisdictions within the United States to Bermuda have created an environment where, notwithstanding that we changed our legal domicile in a transaction that was approved by our shareholders and fully taxable to our company under United States law, we may be exposed to various prejudicial actions, including:

We do not know whether any of these things will happen, but if implemented one or more of them may have an adverse impact on our future operations or our share price.

It may be difficult to enforce a judgment obtained against us because we are a foreign entity.

We are a Bermuda company. All or a substantial portion of our assets, including substantially all of our intellectual property, may be located outside the United States. As a result, it may be difficult for shareholders and others to enforce in United States courts judgments obtained against us. We have irrevocably agreed that we may be served with process with respect to actions based on offers and sales of securities made hereby in the United States by serving Christopher J. Margolin, c/o XOMA Ltd., 2910 Seventh Street, Berkeley, California 94710, our United States agent appointed for that purpose. Uncertainty exists as to whether Bermuda courts would enforce judgments of United States courts obtained in actions against us or our directors and officers that are predicated upon the civil liability provisions of the United States securities laws or entertain original actions brought in Bermuda against us or such persons predicated upon the United States securities laws. There is no treaty in effect between the United States and Bermuda providing for such enforcement, and there are grounds upon which Bermuda courts may not enforce judgments of United States courts. Certain remedies available under the United States federal securities laws may not be allowed in Bermuda courts as contrary to that nation’s policy.

Our shareholder rights agreement or bye-laws may prevent transactions that could be beneficial to our shareholders and may insulate our management from removal.

In February of 2003, we adopted a new shareholder rights agreement (to replace the shareholder rights agreement that had expired), which could make it considerably more difficult or costly for a person or group to acquire control of us in a transaction that our Board of Directors opposes.

Our bye-laws:

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These provisions of our shareholders rights agreement and our bye-laws, alone or in combination with each other, may discourage transactions involving actual or potential changes of control, including transactions that otherwise could involve payment of a premium over prevailing market prices to holders of common shares, could limit the ability of shareholders to approve transactions that they may deem to be in their best interests, and could make it considerably more difficult for a potential acquirer to replace management.

None.

Our corporate headquarters and development and manufacturing facilities are located in Berkeley and Emeryville, California. We currently lease five buildings, and space in a sixth building, for which we are actively seeking a sublease tenant. These buildings house our research and development laboratories, manufacturing facilities and office space. A separate pilot scale manufacturing facility is owned by us. Our building leases expire in the period from 2011 to 2014 and total minimum lease payments due from January of 2010 until expiration of the leases are $19.2 million. We have the option to renew our lease agreements for periods ranging from three to ten years.

On January 15, 2009, we announced a workforce reduction of approximately 42 percent or 144 employees, a majority of which were employed in manufacturing and related support functions. This decision was based on a decrease in forecasted contract manufacturing demand in 2009. As a result, in the second quarter of 2009, we vacated one of our leased buildings resulting in a restructuring charge. In addition, our pilot scale manufacturing facility is temporarily vacant, in order to optimize our facility usage. As manufacturing demand increases in the future, we plan to resume operations at this facility. The net book value of fixed assets in our pilot scale manufacturing facility potentially subject to write-down is approximately $4.2 million as of December 31, 2009.

Due to the decrease in contract manufacturing demand in 2009, our primary leased manufacturing facilities were idle for the majority of 2009. At our pilot scale manufacturing facility, we performed small scale process development of several antibodies in development, pursuant to a drug manufacturing license obtained from the State of California.

In the fourth quarter of 2009, we resumed operations in our primary leased manufacturing facilities. In 2010, we plan to produce multiple anti-botulinum neurotoxin antibodies in support of our contracts with the National Institute of Allergy and Infectious Diseases (“NIAID”), a part of the National Institutes of Health (“NIH”), at these facilities. Subject to future manufacturing demand, we believe that our facilities are suitable and adequate for our current level of operations and anticipated growth in the near future.

On April 9, 2009, a complaint was filed in the Superior Court of Alameda County, California, in a lawsuit captioned Hedrick et al. v. Genentech, Inc. et al, Case No. 09-446158. The complaint asserts claims against Genentech, XOMA Ltd. (the “Company”) and others for alleged strict liability for failure to warn, strict product liability, negligence, breach of warranty, fraudulent concealment, wrongful death and other claims based on injuries alleged to have occurred as a result of three individuals’ treatment with RAPTIVA^®. The complaint

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seeks unspecified compensatory and punitive damages. Since then, additional complaints have been filed in the same court, bringing the total number of pending cases to twenty-one. All of the complaints allege the same claims and seek the same types of damages based on injuries alleged to have occurred as a result of the plaintiffs’ treatment with RAPTIVA^®. The Company’s agreement with Genentech provides for an indemnity of XOMA and payment of legal fees by Genentech which the Company believes is applicable to this matter. The Company believes the claims against it to be without merit and intends to defend against them vigorously.

In September of 2004, XOMA (US) LLC entered into a collaboration with Aphton for the treatment of gastrointestinal and other gastrin-sensitive cancers using anti-gastrin monoclonal antibodies. In May of 2006, Aphton filed for bankruptcy protection under Chapter 11, Title 11 of the United States Bankruptcy Code in the United States Bankruptcy Court for the District of Delaware, No. 06-10510 (CSS). XOMA (US) LLC filed a proof of claim in the proceeding, as an unsecured creditor of Aphton, for approximately $594,000. Aphton and the Official Committee of Unsecured Creditors filed a Proposed Plan of Reorganization (“the Plan”) that would result in a liquidation of Aphton. The creditors have voted in favor of the plan, and the bankruptcy court has confirmed it. A litigation trustee appointed under the Plan is currently pursuing litigation against various parties other than the Company, and any recovery by the Company under the Plan will depend on the outcome of such litigation. It is not presently known what, if any, distributions will be made to holders of unsecured claims. There were no developments material to XOMA in the proceedings involving Aphton during the year ended December 31, 2009.

Supplementary Item: Executive Officers of the Registrant

Our executive officers and their respective ages, as of December 31, 2009, and positions are as follows:

The Board of Directors elects all officers annually. There is no family relationship between or among any of the officers or directors.

Business Experience

Mr. Engle is XOMA’s Chairman, Chief Executive Officer and President. He has more than 25 years of executive leadership and biotechnology and pharmaceutical industry experience and, in February of 2010, was elected to the board of directors of the Biotechnology Industry Organization, or BIO. Prior to joining XOMA in 2007, he served as Chairman of the Board and Chief Executive Officer of La Jolla Pharmaceutical Company, a publicly-held biopharmaceutical company focused on the research and development of therapeutic products for autoimmune and antibody-mediated diseases. He joined La Jolla Pharmaceutical Company in 1993, became President and a Director in 1994, Chief Executive Officer in 1995, and Chairman of the Board in 1997. Prior to joining La Jolla, he held executive-level positions at Cygnus Therapeutic Systems, a developer of drug delivery systems, and Micro Power Systems, Inc., a manufacturer of high technology products, including medical devices. He began his professional career with the Strategic Decisions Group and the Stanford Research Institute. Mr. Engle holds an M.S.E.E. and a B.S.E.E. with a focus in biomedical engineering from the University of Texas.

Dr. Scannon is one of our founders and has served as a Director since our formation. Dr. Scannon became Executive Vice President and Chief Medical Officer in May of 2009. Previously he was our Executive Vice

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President and Chief Biotechnology Officer beginning in May of 2006 and served as Chief Scientific and Medical Officer from March of 1993 until May of 2006, Vice Chairman, Scientific and Medical Affairs from April of 1992 to March of 1993 and our President from our formation until April of 1992. In 2007, Dr. Scannon was invited to join the newly formed National Biodefense Science Board, reporting to the Secretary for the Department of Health and Human Services. In 2007, he also became a member of the Board of Directors for Pain Therapeutics, Inc, a biopharmaceutical company. He serves on the Defense Sciences Research Council for the Defense Advanced Research Projects Agency (DARPA) and on the Threat Reduction Advisory Committee for the Department of Defense. From 1979 until 1981, Dr. Scannon was a clinical research scientist at the Letterman Army Institute of Research in San Francisco. A Board-certified internist, Dr. Scannon holds a Ph.D. in organic chemistry from the University of California, Berkeley and an M.D. from the Medical College of Georgia.

Mr. Kurland is our Vice President, Finance and Chief Financial Officer. He joined XOMA on December 29, 2008. Mr. Kurland is responsible for directing the Company’s financial strategy, accounting, financial planning and investor relations functions. He has more than 30 years of experience in biotechnology and pharmaceutical companies including Aviron/MedImmune, Protein Design Labs and Syntex/Roche. Prior to joining XOMA, Mr. Kurland served as Chief Financial Officer of Bayhill Therapeutics, Inc., Corcept Therapeutics Incorporated and Genitope Corporation. From 1998 to 2002, Mr. Kurland served as Senior Vice President and Chief Financial Officer of Aviron, acquired by MedImmune in 2001 and developer of FluMist. From 1996 to 1998, he was Vice President and Chief Financial Officer of Protein Design Labs, Inc., an antibody design company, and from 1995 to 1996, he served as Vice President and Chief Financial Officer of Applied Immune Sciences, Inc. Mr. Kurland also held a number of financial management positions at Syntex Corporation, a pharmaceutical company acquired by Roche, including Vice President and Controller between 1991 and 1995. He received his J.D. and M.B.A. degrees from the University of Chicago and his B.S. degree from Lehigh University.

Mr. Margolin is our Vice President, General Counsel and Secretary. During his time with the Company, Mr. Margolin has been responsible for the legal and intellectual property function and, at various times, the business development, human resources and licensing functions. Prior to joining us in 1991, Mr. Margolin was a corporate attorney holding several different executive legal positions for Raychem Corporation, an international high technology company, for 11 years. From 1975 to 1980, he was a division counsel for TRW Inc. and from 1972 to 1975, he was an associate at the law firm of McCutchen, Black, Verleger and Shea in Los Angeles. Mr. Margolin holds a B.A. from Princeton University, a J.D. from the University of Pennsylvania and an M.B.A. from the University of California, Los Angeles.

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PART II

Market for Registrant’s Common Equity

Our common shares trade on The NASDAQ Global Market under the symbol “XOMA.” The following table sets forth the quarterly range of high and low reported sale prices of our common shares on The NASDAQ Global Market for the periods indicated:

On March 9, 2010, there were 2,593 shareholders of record of our common shares, one of which was Cede & Co., a nominee for Depository Trust Company (“DTC”). All of the common shares held by brokerage firms, banks and other financial institutions as nominees for beneficial owners are deposited into participant accounts at DTC and are therefore considered to be held of record by Cede & Co. as one shareholder.

Dividend Policy

We have not paid dividends on our common shares. We currently intend to retain any earnings for use in the development and expansion of our business. We, therefore, do not anticipate paying cash dividends on our common shares in the foreseeable future.

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Performance Graph

The following graph compares the five-year cumulative total shareholder return for XOMA common stock with the comparable cumulative return of certain indices. The graph assumes $100 invested on the same date in each of the indices. Returns of the company are not indicative of future performance.

FIVE-YEAR PERFORMANCE GRAPH

Debt and Equity Issuances

ATM Agreement

In the third quarter of 2009, we entered into an At Market Issuance Sales Agreement (the “ATM Agreement”), with Wm Smith & Co. (“Wm Smith”), under which we may sell up to 25 million of our common shares from time to time through Wm Smith, as the agent for the offer and sale of the common shares. Wm Smith may sell these common shares by any method permitted by law deemed to be an “at the market” offering as defined in Rule 415 of the Securities Act of 1933, including but not limited to sales made directly on The NASDAQ Global Market, on any other existing trading market for the common shares or to or through a market maker. Wm Smith may also sell the common shares in privately negotiated transactions, subject to our approval. We pay Wm Smith a commission equal to 3% of the gross proceeds of all common shares sold through it as sales agent under the ATM Agreement but in no event less than $0.02 per share. Shares sold under the ATM Agreement are sold pursuant to a prospectus which forms a part of a registration statement declared effective by the Securities and Exchange Commission on May 29, 2008. From the inception of the ATM Agreement through December 31, 2009, we sold a total of 4,050,617 common shares through Wm Smith for aggregate gross proceeds of $2.9 million. Total offering expenses related to these sales were $0.1 million. Refer to Item 7: Management’s Discussion and Analysis of Financial Condition and Results of Operations: Subsequent Events for disclosure regarding the number of common shares sold under this agreement subsequent to the end of 2009.

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Registered Direct Offerings

In May of 2009, we entered into a definitive agreement with an institutional investor to sell 11,764,706 units, with each unit consisting of one of our common shares and a warrant to purchase 0.50 of a common share, for gross proceeds of approximately $10 million, before deducting placement agent fees and estimated offering expenses of $0.8 million, in a registered direct offering. The investor purchased the units at a price of $0.85 per unit. The warrants, which represent the right to acquire an aggregate of up to 5,882,353 common shares, were exercisable at any time on or after May 15, 2009 and prior to May 20, 2014 at an exercise price of $1.02 per share. As of December 31, 2009, all warrants issued in May of 2009 remained outstanding. Refer to Item 7: Management’s Discussion and Analysis of Financial Condition and Results of Operations: Subsequent Events for disclosure regarding certain amendments made to the terms of the warrants issued in May of 2009 and the number of shares issued upon exercise of these warrants subsequent to the end of 2009.

In June of 2009, we entered into a definitive agreement with certain institutional investors to sell 10,434,782 units, with each unit consisting of one of our common shares and a warrant to purchase 0.50 of a common share, for gross proceeds of approximately $12 million, before deducting placement agent fees and estimated offering expenses of $0.8 million, in a second registered direct offering. The investor purchased the units at a price of $1.15 per unit. The warrants, which represent the right to acquire an aggregate of up to 5,217,391 common shares, are exercisable at any time on or prior to December 10, 2014 at an exercise price of $1.30 per share. As of December 31, 2009, all warrants issued in June of 2009 remained outstanding. Refer to Item 7: Management’s Discussion and Analysis of Financial Condition and Results of Operations: Subsequent Events for disclosure regarding certain amendments made to the terms of the warrants issued in June of 2009 subsequent to the end of 2009.

Equity Line of Credit

On October 21, 2008, we entered into a common share purchase agreement (the “Purchase Agreement”) with Azimuth Opportunity Ltd. (“Azimuth”), pursuant to which we obtained a committed equity line of credit facility (the “Facility”) under which we could sell up to $60 million of our registered common shares to Azimuth over a 24-month period, subject to certain conditions and limitations. The Purchase Agreement required a minimum share price of $1.00 per share to allow us to issue shares to Azimuth under the Facility. However, at its election, Azimuth could buy shares below the threshold price at a negotiated discount. We were not obligated to utilize any of the $60 million Facility and remained free to enter other financing transactions. Shares under the Facility were sold pursuant to a prospectus which forms a part of a registration statement declared effective by the Securities and Exchange Commission on May 29, 2008. At the end of the third quarter of 2009, the Facility was no longer in effect, and no additional shares could be issued thereunder.

From the inception of the Facility in October of 2008 through 2009, we sold a total of 42,228,428 common shares to Azimuth for aggregate gross proceeds of $33.9 million. This included the sale of 4.0 million shares under the Facility in December of 2008 and 34.3 million shares in two transactions in September of 2009 that Azimuth agreed to purchase notwithstanding that the purchase prices were below the minimum price of $1.00 required by the Purchase Agreement. We negotiated a discount rate (excluding placement agent fees) of 8.86% for the sale in December of 2008 and 8.0% for the sales in September of 2009. Prior to the successful conclusion of negotiations, Azimuth was not obligated to purchase these shares. Offering expenses incurred from the inception of the Facility through 2009 related to sales to Azimuth were $0.7 million.

Proceeds from the sale of shares under the ATM Agreement, registered direct offerings and under the equity line of credit are being used to continue development of our XOMA 052 product candidate and for other working capital and general corporate purposes.

Convertible Debt

In February of 2006, we completed an exchange offer with holders of our 6.5% convertible senior notes due 2012 in which we exchanged $60 million aggregate principal amount of 6.5% Convertible SNAPs_SM due 2012

(the “New Notes”) for all $60 million aggregate principal amount of our then outstanding convertible senior

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notes due 2012. We also issued an additional $12 million of New Notes to the public for cash at a public offering price of 104% of principal, or $12.5 million.

During the first quarter of 2007, holders voluntarily converted $42 million of our New Notes and we converted the $2.5 million of our New Notes that remained outstanding (the other $27.5 million thereof having been converted in 2006). As a result, 25,640,187 shares were issued to effect the conversion of the principal balances. Additionally, at the time of conversion, we issued 1,889,317 shares and $5.2 million in cash to satisfy the remaining additional interest payment feature related to these converted New Notes.

For the year ended December 31, 2007, we incurred $0.2 million in interest expense related to our convertible debt, amortized $0.1 million in debt issuance costs, premium and discount, and recognized $6.1 million in interest expense related to the revaluation of the embedded derivative.

The following table contains our selected financial information including consolidated statement of operations and consolidated balance sheet data for the years 2005 through 2009. The selected financial information has been derived from our audited consolidated financial statements. The selected financial information should be read in conjunction with Item 8: Financial Statements and Supplementary Data and Item 7: Management’s Discussion and Analysis of Financial Condition and Results of Operations included in this Annual Report. The data set forth below is not necessarily indicative of the results of future operations.

We have paid no dividends in the past five years.

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Overview

We are a leader in the discovery, development and manufacture of therapeutic antibodies designed to treat inflammatory, autoimmune, infectious and oncological diseases. Our proprietary development pipeline includes XOMA 052, an anti-interleukin-1 beta (“IL-1 beta”) antibody, XOMA 3AB, a biodefense anti-botulism antibody candidate, and preclinical antibody discovery programs in several indications. We have a fully integrated product development platform, extending from preclinical science to development and manufacturing. We have multiple revenue streams resulting from the licensing of our antibody technologies, biodefense contracts and discovery and development collaborations and product royalties. Our technologies have contributed to the success of marketed antibody products, including LUCENTIS^® (ranibizumab injection) for wet age-related macular degeneration and CIMZIA^® (certolizumab pegol) for rheumatoid arthritis and Crohn’s disease.

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We have established on-going technology licensing programs for certain of our proprietary technologies, which have attracted numerous significant licensees including Bayer Heathcare AG, Johnson & Johnson (formerly Centocor, Inc.), Merck & Co., Inc. (“Merck”), Pfizer Inc. (“Pfizer”) and Takeda Pharmaceutical Company Limited (“Takeda”). We have a premier antibody discovery and development platform that includes multiple antibody discovery or phage display libraries that increase our ability and that of our partners to discover new therapeutic antibodies. Once an antibody is discovered, we use a number of proprietary technologies including our Human Engineering™, affinity maturation, bacterial cell expression and manufacturing technologies to enhance and improve the qualities of the antibodies for efficacy, safety, stability, productivity and cost. Some of XOMA’s technologies are used widely across the industry and have generated significant revenues for the company. For example, bacterial cell expression technology is a key biotechnology for the discovery and manufacture of antibodies and other proteins. Thus far, more than 50 pharmaceutical and biotechnology companies have signed bacterial cell expression licenses with us, and a number of licensed product candidates are in clinical development.

Our biodefense initiatives currently include a $65 million multiple-year contract funded by the National Institute of Allergy and Infectious Diseases (“NIAID”), a part of the National Institutes of Health (“NIH”), to support our ongoing development of drug candidates toward clinical trials in the treatment of botulism poisoning. This contract is the third that NIAID has awarded us for the development of botulinum antitoxins and brings the program’s total awards to nearly $100 million. We also develop products with premier pharmaceutical companies including Novartis AG (“Novartis”), Schering-Plough Research Institute, a division of Schering Corporation, now a subsidiary of Merck (referred to herein as “Merck/Schering-Plough”) and Takeda.

Significant Developments in 2009

XOMA 052 and Proprietary Pipeline

Biodefense

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Technology Licensing and Collaboration Agreements

Royalties

Financial

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Other

Critical Accounting Estimates

The accompanying discussion and analysis of our financial condition and results of operations are based upon our consolidated financial statements and the related disclosures, which have been prepared in accordance with accounting principles generally accepted in the United States. The preparation of these financial statements requires us to make estimates, assumptions and judgments that affect the reported amounts in our consolidated financial statements and accompanying notes. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.

We believe the following policies to be the most critical to an understanding of our financial condition and results of operations because they require us to make estimates, assumptions and judgments about matters that are inherently uncertain.

Revenue Recognition

Revenue is recognized when the four basic criteria of revenue recognition are met: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred or services have been rendered; (3) the fee is fixed and determinable; and (4) collectibility is reasonably assured. The determination of criteria (2) is based on management’s judgments regarding whether a continuing performance obligation exists. The determination of criteria (3) and (4) are based on management’s judgments regarding the nature of the fee charged for products or services delivered and the collectibility of those fees. Allowances are established for estimated uncollectible amounts, if any.

We recognize revenue from license and collaboration arrangements, contract services and royalties. Our revenue arrangements with multiple elements are divided into separate units of accounting if certain criteria are met, including whether the delivered element has stand-alone value to the customer and whether there is objective and reliable evidence of the fair value of the undelivered items. The consideration we receive is allocated among the separate units based on their respective fair values and the applicable revenue recognition criteria are applied to each of the separate units. Advance payments received in excess of amounts earned are classified as deferred revenue until earned.

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License and Collaborative Fees

Revenue from non-refundable license, technology access or other payments under license and collaborative agreements where we have a continuing obligation to perform is recognized as revenue over the expected period of the continuing performance obligation. We estimate the performance period at the inception of the arrangement and reevaluate it each reporting period. This reevaluation may shorten or lengthen the period over which the remaining revenue is recognized. Changes to these estimates are recorded on a prospective basis.

Milestone payments under collaborative and other arrangements are recognized as revenue upon completion of the milestone event, once confirmation is received from the third party and collectibility is reasonably assured. This represents the culmination of the earnings process because we have no future performance obligations related to the payment. Milestone payments that require a continuing performance obligation on our part are recognized over the expected period of the continuing performance obligation. Amounts received in advance are recorded as deferred revenue until the related milestone is completed.

Contract Revenue

Contract revenue for research and development involves our providing research and development and manufacturing services to collaborative partners, biodefense contractors or others. Revenue for certain contracts is accounted for by a proportional performance, or output-based, method where performance is based on estimated progress toward elements defined in the contract. The amount of contract revenue and related costs recognized in each accounting period are based on estimates of the proportional performance during the period. Adjustments to estimates based on actual performance are recognized on a prospective basis and do not result in reversal of revenue should the estimate to complete be extended.

In addition, revenue related to certain research and development contracts is billed based on actual costs incurred by XOMA related to the contract, multiplied by full-time equivalent (“FTE”) rates plus a mark-up. The FTE rates are developed based on our best estimates of labor, materials and overhead costs. For certain contracts, the FTE rates are agreed upon at the beginning of the contract and are subject to review or audit by the contracting party at any time.

For example, in the third quarter of 2008, we disclosed a change in accounting estimate as a result of an audit by the NIH of the Company’s 2007 actual data, from which the NIH developed billing rates for the period from January 2007 to June 2009 to be used for all of the Company’s contracts with NIAID, including Contract No. HHSN26620060008C/N01-A1-60008 (“NIAID 2”). While the audited NIH rates are considered final for 2007 billings, these NIH rates are considered provisional for the period from January of 2008 to June of 2009 and thus are subject to future audits at the discretion of NIAID’s contracting office. In September of 2008, we retroactively applied these NIH rates to the invoices from 2007 through the third quarter of 2008 resulting in an adjustment to decrease revenue by $2.7 million.

Up-front fees are recognized ratably over the expected benefit period under the arrangement. Given the uncertainties of research and development collaborations, significant judgment is required to determine the duration of the arrangement. We have $4.5 million of deferred up-front fees related to two research and collaboration agreements that are being amortized over a range of two to five years.

Royalty Revenue

Royalty revenue and royalty receivables are generally recorded in the periods these royalties are earned, in advance of collection. The royalty revenue and receivables in these instances are based upon communication with collaborative partners, historical information and forecasted sales trends.

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Research and Development Expenses

We expense research and development expenses as incurred. Research and development expenses consist of direct costs such as salaries and related personnel costs and material and supply costs, and research-related allocated overhead costs, such as facilities costs. In addition, research and development expenses include costs related to clinical trials. Expenses resulting from clinical trials are recorded when incurred based in part on estimates as to the status of the various trials. From time to time, research and development expenses may include up-front fees and milestones paid to collaborative partners for the purchase of rights to in-process research and development. Such amounts are expensed as incurred. The timing of up-front fees and milestone payments in the future may cause variability in our future research and development expenses.

Share-Based Compensation

The valuation of share-based compensation awards is determined at the date of grant using the Black-Scholes option pricing model. This model requires inputs such as the expected term of the option, expected volatility and risk-free interest rate. Further, the forfeiture rate also impacts the amount of aggregate compensation. These inputs are subjective and generally require significant analysis and judgment to develop. To establish an estimate of expected term, we consider the vesting period and contractual period of the award and our historical experience of share option exercises, post-vesting cancellations and volatility. To establish an estimate of forfeiture rate, we consider our historical experience of option forfeitures and terminations. The risk-free rate is based on the yield available on United States Treasury zero-coupon issues. We review our valuation assumptions quarterly and, as a result, it is likely we will change our valuation assumptions used to value share-based awards granted in future periods.

Share-based compensation expense is recognized ratably over the requisite service period. If options are granted that include a performance condition, we estimate the probability of the performance condition being achieved on a quarterly basis. If it is determined that it is probable the performance criteria will be achieved, we estimate an implicit service period from grant date to the most likely date of achievement of the performance criteria and record share-based compensation expense ratably over this implicit service period. These estimates require significant judgment and may change in future periods.

Income Taxes

The application of income tax law and regulations is inherently complex. Interpretations and guidance surrounding income tax laws and regulations change over time. As such, changes in our subjective assumptions and judgments can materially affect amounts recognized in our financial statements.

We account for uncertain tax positions in accordance with Accounting Standards Codification Topic 740, Income Taxes (“ASC 740”). ASC 740 provides for the recognition of deferred tax assets if realization of such assets is more likely than not. Based upon the weight of available evidence, which includes our historical operating performance and carry-back potential, we have determined that total deferred tax assets should be fully offset by a valuation allowance.

Long-Lived Assets

We record impairment losses on long-lived assets used in operations when events and circumstances indicate that the assets might be impaired and the undiscounted cash flows estimated to be generated by those assets in the future are less than the carrying amounts of those assets. The estimate of future cash flows requires significant judgment related to potential future business opportunities being pursued by the Company.

Accrued Management Incentive Compensation

We estimate an accrual on a quarterly basis for the annual management incentive compensation plan, which is paid to employees in March of the following year. This estimate involves assessing the year’s achievements on a corporate and individual employee level against our objectives set at the beginning of the year, and is subject to change each quarter.

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Accrued Restructuring Costs

In the second quarter of 2009, we vacated one of our leased buildings and are currently seeking a sublease tenant. We recorded a restructuring charge in the second quarter of 2009 for the net present value of the future minimum lease payments, offset by potential future sublease payments. If the amount of sublease income changes in the future based on changes in our estimates, we will adjust the related liability for the estimated net present value of the lease.

Warrant Liabilities

We issued warrants to purchase our common shares in connection with two separate registered direct offerings completed in May and June of 2009. The warrants issued included a provision allowing for an adjustment of the exercise price and number of warrant shares. This adjustment would occur if we issued or sold certain common shares in the future for a price per share less than the exercise price of the warrants in effect immediately prior to such issuance or sale. Due to this adjustment provision, the warrants did not meet the criteria set forth by Accounting Standards Codification Topic 815, Derivatives and Hedging (“ASC 815”) and therefore were not considered indexed to our own stock.

We estimated the fair value of the warrants at the issuance dates using the Monte Carlo Simulation Model (“Simulation Model”) and recorded warrant liabilities. The Simulation Model requires inputs such as the expected term of the warrants, share price volatility, risk-free interest rate and the likelihood and timing of future equity financings. These assumptions were reviewed on a quarterly basis and changes in the estimated fair value of the warrants were recognized in other income (expense).

Subsequent to the end of 2009, the warrant holders agreed to amend certain terms of these warrants, as disclosed below in the Subsequent Events section.

Loss Contingencies

We are currently, and have been, involved in certain legal proceedings for which we assess the likelihood of any adverse judgments or outcomes for these legal matters, as well as potential ranges of probable losses. We would record an estimated loss in our statement of operations if we determined that, based on information available at the time, the loss is probable and the amount of the loss is reasonably estimable. The nature of these matters is highly uncertain and subject to change. As a result, any contingent liabilities recorded may vary on a quarterly basis, and depending on the final outcome of such legal proceedings.

Results of Operations

Revenue

Total revenue in 2009 was $98.4 million, compared with $68.0 million in 2008 and $84.3 million in 2007 as shown in the table below (in thousands):

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License and Collaborative Fees

License and collaborative fee revenue includes fees and milestone payments related to the out-licensing of our products and technologies. License and collaborative fee revenue in 2009 was $43.8 million, compared with $16.4 million in 2008 and $36.5 million in 2007. The primary components of license and collaborative fee revenue in 2009 were $28.1 million in revenue recognized related to the expansion of our collaboration agreement with Takeda in February of 2009 and $14.1 million in total revenue, including ancillary services provided, related to two antibody discovery collaboration agreements entered into with Arana and Kaketsuken in September and October of 2009. We also recognized $1.6 million of license and collaborative fee revenue in 2009 related to up-front fees, annual maintenance fees and milestone payments from various out-licensing arrangements.

The primary source of license and collaborative fee revenue in 2008 related to the restructuring of our product development collaboration with Novartis, which involved six development programs including the HCD122 program. Under the restructured agreement, we recognized a collaborative fee of $13.7 million in exchange for giving Novartis control over the HCD122 program and an additional program, as well as the right to expand the development of these programs into additional indications outside of oncology. We also recognized $1.7 million in up-front fees and annual maintenance fees relating to various out-licensing arrangements. In addition, we recognized four milestone payments totaling $1.0 million, including two milestone payments from Pfizer relating to two different products, including the payment of $0.5 million for the initiation of a Phase 3 clinical trial.

The primary source of license and collaborative fees in 2007 related to payments received from Pfizer and an existing technology partner totaling $31.3 million. These payments represented initial license fees for which no remaining obligation of the Company existed. In addition, $4.3 million in revenue was recognized during the first quarter of 2007 representing the unamortized revenue from a $10 million up-front collaboration fee received in connection with our collaboration with Novartis (then Chiron) in February of 2004. In February of 2007, we announced that pursuant to the terms of our collaboration agreement with Novartis, the mutual exclusivity obligation to conduct antibody discovery, development and commercialization work in oncology had ended. The expiration of this mutual obligation had no impact on the existing collaboration projects which had reached the development stage and the parties could continue to collaborate on a non-exclusive basis. Prior to the expiration of the exclusivity period, the up-front fee was being amortized over the expected five-year term of the exclusivity provision, or at a rate of $0.5 million per quarter.

The generation of future revenue related to license fees and collaborative arrangements is dependent on our ability to attract new licensees to our antibody and bacterial cell expression technologies and new collaboration partners. Depending on whether and when we obtain new licensees and partners, we expect to experience a decline from 2009 levels.

Contract and Other Revenue

Contract and other revenue was $25.5 million in 2009, compared with $30.5 million in 2008 and $31.1 million in 2007. This revenue includes agreements where we provide contracted research and development and manufacturing services to our collaboration partners, including Takeda, Merck/Schering-Plough and NIAID.

Contract and other revenue recognized in 2009 included $7.6 million related to our Merck/Schering-Plough contract, compared with $10.8 million in 2008. The decrease in revenue under this contract of $3.2 million was due to the cessation of certain discovery and development programs under our collaboration agreement in 2009. Revenue from our Manufacturing and Technology Transfer Agreement with Novartis decreased in 2009 by $4.1 million, from $6.6 million in 2008 to $2.5 million in 2009, due to the completion of the work under this agreement in the third quarter of 2009. In addition, revenue from our AVEO Pharmaceuticals, Inc. (now with Merck/Schering-Plough and referred to herein together as “Merck/Schering-Plough/AVEO”) contract decreased by $2.5 million, from $3.2 million in 2008 to $0.7 million in 2009, as a result of our nearing the end of the contracted service arrangement.

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These decreases in contract and other revenue in 2009 were partially offset by an increase in revenue generated under our contract with NIAID Contract No. HHSN272200800028C (“NIAID 3”) of $0.9 million, from $4.2 million in 2008 to $5.1 million in 2009. Additionally, we recognized $2.8 million of unamortized deferred revenue in the fourth quarter of 2009 related to the cessation of certain discovery and development programs under our collaboration with Takeda, resulting in an increase in contract revenue recognized related to our collaboration with Takeda of $3.1 million, from $4.4 million in 2008 to $7.5 million in 2009.

In the third quarter of 2009, we began work on two biodefense subcontract awards from SRI International, including a $1.7 million award to develop novel antibody drugs against the virus that causes severe acute respiratory syndrome and a $2.2 million award to develop a novel antibody, known as F10, that has been shown to neutralize group 1 influenza A viruses, including the H1N1 and H5N1 strains. The subcontract awards are funded through NIAID. Revenue recognized in 2009 relating to these subcontracts was $0.3 million.

Contract and other revenue recognized in 2008 included $4.2 million related to NIAID 3, which was awarded in September of 2008, and $6.6 million relating to our Manufacturing and Technology Transfer Agreement with Novartis signed in December of 2008, and effective from July of 2008. We also recognized $10.8 million in revenue in 2008 from our agreement with Merck/Schering-Plough, compared with $5.7 million in 2007, and $4.4 million in revenue in 2008 from our agreement with Takeda, compared with $3.1 million in 2007. These increases in contract and other revenue were offset by decreases in revenue recognized from our NIAID 2 contract from $11.3 million in 2007 to $1.3 million in 2008, and on our Merck/Schering-Plough/AVEO contract from $8.0 million in 2007 to $3.2 million in 2008. These decreases are primarily due to the Company nearing the end of contracted service arrangements with NIAID 2 and Merck/Schering-Plough/AVEO. Contract revenue for 2008 also included an adjustment for NIAID 2 to decrease revenue by $2.7 million due to a change in billing rates, as detailed above in the Critical Accounting Estimates: Contract Revenue section.

Based on expected increases in revenue related to our NIAID 3 contract and our subcontract awards from SRI International, partially offset by decreases in contract revenue from other collaboration partners, we expect contract and other revenue in 2010 to remain comparable to 2009 levels or slightly increase depending on the timing and level of revenue generating activity.

We defer revenue until all requirements under our revenue recognition policy are met. In 2009, we deferred $16.2 million of revenue from five contracts including Takeda, Merck/Schering-Plough and Novartis and recognized $28.4 million in revenue from the five contracts. In 2008, we deferred $17.5 million of revenue from five contracts including Merck/Schering-Plough, Takeda and Novartis and recognized $18.4 million in revenue from the five contracts. In 2007, we deferred $23.3 million of revenue from five contracts including Merck/Schering-Plough, Merck/Schering-Plough/AVEO, Takeda and Novartis and recognized $22.2 million in revenue from the five contracts including amortization of $4.3 million of the $10 million in up-front payments received from Novartis related to our February of 2004 oncology collaboration contract.

The following table shows the activity in deferred revenue for the years ended December 31, 2009, 2008 and 2007 (in thousands):

Of the $5.0 million balance in deferred revenue at December 31, 2009, $2.1 million is expected to be earned over the next year and the remaining $2.9 million is expected to be earned over the next four years. Future

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amounts may be affected by additional consideration received, if any, under existing or any future licensing or other collaborative arrangements as well as changes in the estimated period of obligation or services to be provided under the arrangements.

Royalties

Revenue from royalties was $29.1 million in 2009 compared with $21.1 million in 2008 and $16.7 million in 2007. The increase in royalties in 2009 was primarily due to the sale of our LUCENTIS^® royalty interest to Genentech for a total of $25 million, which included the receipt of royalties of $2.7 million recognized in the second quarter of 2009 and an additional one-time, non-refundable payment of $22.3 million in September of 2009. Royalties earned from sales of LUCENTIS^® for the first half of 2009 were $5.1 million. We will not receive any further royalties on sales of LUCENTIS^®.

The cessation of royalties earned from sales of RAPTIVA^® in the second quarter of 2009 partially offsets the increase in royalty revenue in 2009. RAPTIVA^® was withdrawn from the commercial drug markets in the first half of 2009. Royalties earned from sales of RAPTIVA^® in 2009 were $1.2 million.

Royalties earned from sales of CIMZIA^® were $0.5 million in 2009, compared with $0.1 million in 2008. CIMZIA^® was approved by the FDA in May of 2009 and in Canada in September of 2009 for the treatment of moderate-to-severe rheumatoid arthritis in adults. We expect royalty revenue from sales of CIMZIA^® to increase in 2010.

Royalties earned in 2008 included $6.5 million from U.S. sales of RAPTIVA^®, compared with $6.4 million in 2007, and royalties of $5.7 million from sales of RAPTIVA^® outside the U.S., compared with $4.2 million in 2007. In addition, royalties earned on U.S sales of LUCENTIS^® were $4.4 million in 2008, compared with $4.1 million in 2007, and royalties earned on sales of LUCENTIS^® outside the U.S. were $4.4 million in 2008, compared with $1.9 million in 2007.

The increase in royalty revenue from 2007 to 2008 resulted from higher sales of LUCENTIS^® and RAPTIVA^® in the U.S. and worldwide. According to Genentech, U.S sales of RAPTIVA^® during 2008 were $108 million, compared with $107 million during 2007. According to Merck Serono, sales of RAPTIVA^® outside of the U.S. during 2008 were approximately $134 million, compared with $106 million during 2007. According to Genentech, U.S. sales of LUCENTIS^® were $875 million during 2008 compared with $815 million during 2007. According to Novartis, sales of LUCENTIS^® outside the United States were $886 million in 2008 compared with $393 million during 2007.

Research and Development Expenses

Biopharmaceutical development includes a series of steps, including in vitro and in vivo preclinical testing, and Phase 1, 2 and 3 clinical studies in humans. Each of these steps is typically more expensive than the previous step, but actual timing and the cost to us depends on the product being tested, the nature of the potential disease indication and the terms of any collaborative arrangements with other companies. After successful conclusion of all of these steps, regulatory filings for approval to market the products must be completed, including approval of manufacturing processes and facilities for the product. Our research and development expenses currently include costs of personnel, supplies, facilities and equipment, consultants, third party costs and other expenses related to preclinical and clinical testing.

Research and development expenses were $58.1 million in 2009, compared with $82.6 million in 2008 and $66.2 million in 2007. The decrease in research and development expense of $24.5 million in 2009, as compared to 2008, was primarily a result of our increased focus on cost control. In addition, spending on Novartis and Merck/Schering-Plough/AVEO-related contract activities decreased in 2009 due to our reaching the end of contracted service arrangements, and spending on Merck/Schering-Plough-related contract activities decreased in 2009 due to the cessation of certain discovery and development programs under the collaboration. Spending on

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XOMA 052 decreased in 2009, as compared to 2008, due to the completion of Phase 1 clinical trial enrollment in the second quarter of 2009 slightly offset by an increase in spending in the fourth quarter of 2009 related to the initiation of the Phase 2 clinical program. In addition, spending on XOMA 629 decreased in 2009, as compared to 2008, due to the Company’s decision to suspend development of this product. These decreases were partially offset by increased spending on preclinical antibody discovery programs in several indications, and on our contracts with NIAID 3, Takeda and SRI International.

The $16.4 million increase in research and development expense in 2008, compared with 2007, primarily reflects increased spending on development of XOMA 052, including Phase 1 clinical trials, and to a lesser extent XOMA 629. In addition, we increased spending on our contracts with Novartis, Merck/Schering-Plough, NIAID 3 and Takeda. Research and development expenses also increased in 2008 related to the preclinical development of several antibodies, XOMA 3AB and upgrades made to our manufacturing plant. These increases were partially offset by a decrease in spending on NIAID 2 and Merck/Schering-Plough/AVEO-related contract activities, due to the Company nearing the end of contracted service arrangements.

Research and development expense in 2007 primarily related to spending on development of XOMA 052, including the initiation of Phase 1 clinical trials, and on the development of XOMA 629. In addition, we increased spending on our contracts with NIAID 2, Merck/Schering-Plough/AVEO, Merck/Schering-Plough and Takeda.

Salaries and related personnel costs are a significant component of research and development expenses. We recorded $26.8 million in research and development salaries and employee-related expenses in 2009, compared with $34.4 million in 2008 and $31.5 million in 2007. Included in these expenses for 2009 were $22.2 million for salaries and benefits, $2.4 million for bonus expense and $2.2 million for share-based compensation, which is a non-cash expense. The decrease of $7.6 million in 2009, as compared to 2008, was due to a decrease in salaries and benefits of $9.9 million due to the workforce reduction announced in January of 2009. In addition, share-based compensation decreased by $0.1 million. See Results of Operations: Share-Based Compensation for further discussion of our share-based compensation expense. Partially offsetting this decrease in research and development personnel expense was an increase in bonus expense in 2009 of $2.4 million. In 2008, the Company did not to pay bonuses in efforts to control spending and manage the Company’s cash balance.

Included in these expenses for 2008 were $32.1 million for salaries and benefits and $2.3 million for share-based compensation, which is a non-cash expense, compared with $27.9 million and $1.0 million, respectively, in 2007. The $2.9 million increase in salaries and employee-related expenses in 2008, as compared to 2007, primarily related to increased headcount. Partially offsetting the 2008 increase in salaries and employee-related expenses was a decrease in bonus expense for 2008 to zero compared with $2.6 million in 2007. As discussed above, the Company did not to pay bonuses for 2008.

Our research and development activities can be divided into earlier stage programs and later stage programs. Earlier stage programs include molecular biology, process development, pilot-scale production and preclinical testing. Also included in earlier stage programs are costs related to excess manufacturing capacity, which we expect will decrease in 2010 due to the consolidation of facilities. Later stage programs include clinical testing, regulatory affairs and manufacturing clinical supplies. The costs associated with these programs approximate the following (in thousands):

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Our research and development activities can also be divided into those related to our internal projects and those projects related to collaborative and contract arrangements. The costs related to internal projects versus collaborative and contract arrangements approximate the following (in thousands):

In 2009 and 2008, our largest development program (XOMA 052) accounted for more than 20% but less than 30% of our total research and development expense. In 2009, one development program (NIAID) accounted for more than 10% but less than 20% of our total research and development expense, and in 2008, one development program (Novartis) accounted for more than 10% but less than 20% of our total research and development expense. No development program accounted for more than 30% of our total research and development expense in 2009 or 2008. In 2007, two development programs (XOMA 052 and NIAID) each individually accounted for more than 10% but less than 20% of our total research and development expense. No development program accounted for more than 20% of our total research and development expense in 2007.

We expect our research and development spending in 2010 will increase due to the initiation of our Phase 2 clinical program for XOMA 052 in Type 2 diabetes and cardiovascular disease and in support of our biodefense contracts. We continue ongoing discussions with a number of companies for a partnership to develop and commercialize XOMA 052.

Future research and development spending may also be impacted by potential new licensing or collaboration arrangements, as well as the termination of existing agreements. Beyond this, the scope and magnitude of future research and development expenses are difficult to predict at this time.

Selling, General and Administrative Expenses

Selling, general and administrative expenses include salaries and related personnel costs, facilities costs and professional fees. In 2009, selling, general and administrative expenses were $23.7 million compared with $24.1 million in 2008 and $20.6 million in 2007. The $0.4 million decrease in selling, general and administrative expenses in 2009 as compared with 2008 was primarily related to a decrease in salaries and related personnel costs of $0.6 million, as further discussed below, as well as a decrease in professional fees and other expenses of $1.2 million due to our increased focus on cost control. Partially offsetting these decreases was an increase in fees in 2009 of $1.4 million related to the restructuring negotiations and repayment of the Goldman Sachs term loan discussed in further detail below in the Liquidity and Capital Resources section.

The $3.5 million increase in selling, general and administrative expenses in 2008 as compared with 2007 was primarily related to a $1.2 million increase in legal fees supporting our technology licensing and collaboration agreements as well as the protection of our intellectual property, a $1.1 million increase in spending related to the marketing and communication of our technology and proprietary products to potential corporate partners and investors, a $0.9 million increase in consulting fees primarily related to employee training and system implementation and a net increase in salaries and related expenses of $0.6 million.

We recorded salaries and employee-related expenses of $12.7 million in 2009 compared with $13.3 million in 2008 and $12.7 million in 2007. The decrease of $0.6 million in 2009 as compared to 2008 was due to a decrease in salaries and benefits of $1.5 million primarily due to the workforce reduction announced in January of 2009, and a decrease in share-based compensation of $0.4 million. See Results of Operations: Share-Based Compensation for further discussion of our share-based compensation expense. Partially offsetting this decrease in selling, general and administrative personnel expense was an increase in bonus expense in 2009 of $1.3 million. In 2008, the Company did not to pay bonuses in efforts to control spending and manage the Company’s cash balance.

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The $0.6 million increase in salaries and employee-related expenses in 2008 as compared to 2007 primarily related to increased headcount. Salaries and benefits expense increased by $1.2 million in 2008 and share-based compensation increased by $0.8 million. See Results of Operations: Share-Based Compensation for further discussion of our share-based compensation expense. Partially offsetting the increase in selling, general and administrative personnel expense was a decrease in bonus expense for 2008 to zero compared with $1.4 million in 2007. As discussed above, the Company did not to pay bonuses for 2008.

We expect selling, general and administrative expenses in 2010 will be comparable to 2009 levels.

Restructuring Charges

In January of 2009, we announced a workforce reduction of approximately 42%. As part of this workforce reduction, we recorded charges of $3.1 million during 2009 related to severance, other termination benefits and outplacement services. In the third quarter of 2009, employee severance and other termination benefits related to the January of 2009 workforce reduction were fully paid. We do not expect to incur any additional restructuring charges for employee severance and other termination benefits related to the January of 2009 workforce reduction.

As a result of the workforce reduction, in the second quarter of 2009, we vacated one of our leased buildings resulting in a restructuring charge of $0.5 million. This charge was primarily related to the net present value of the future minimum lease payments, less the estimated future sublease income. We are currently seeking a sublease tenant. At the end of 2009, one building remains temporarily vacant, in order to optimize our facility usage. As manufacturing demand increases in the future, we plan to resume operations at this facility. As of December 31, 2009, we performed an analysis of the long-lived assets related to the vacant building, with an approximate net book value of $4.2 million. Based on estimated undiscounted future cash inflows, we have determined that there is no current impairment relating to these assets, and will continue to assess for impairment at each future reporting period.

Other Income (Expense)

Investment and interest income was $49,000 in 2009 compared with $0.9 million in 2008 and $1.9 million in 2007. Investment and interest income consists primarily of interest earned on our cash and investment balances. The differences between 2009, 2008 and 2007 balances resulted from varying average cash and investment balances and interest rates.

Interest expense and amortization of debt issuance costs for the Goldman Sachs term loan, to the date of repayment, and Novartis note are shown below for 2009, 2008 and 2007 (in thousands):

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Interest expense was $4.9 million in 2009, compared with $7.0 million in 2008 and $11.6 million in 2007. The decrease in interest expense in 2009 of $2.1 million as compared to 2008 was due to a decrease in interest expense and amortization of debt issuance costs on the Goldman Sachs term loan of $1.4 million. This decrease was due to the repayment in full of the term loan facility in September of 2009, at which point the remaining debt issuance costs of $1.1 million were recognized as part of the loss on debt extinguishment in our consolidated statement of operations for 2009. In addition, interest expense related to the Novartis note decreased by $0.7 million in 2009 due to a decrease in the average principal balance and interest rate of this note. Refer to the Liquidity and Capital Resources: Goldman Sachs Term Loan section for additional disclosure regarding the loan repayment.

The decrease in interest expense of $4.6 million in 2008 compared to 2007 is primarily due to the elimination of our convertible debt in 2007, which represented $6.5 million of interest expense in 2007, including $6.1 million related to the revaluation to fair value of the embedded derivative on our convertible debt. This decrease was partially offset by an increase in interest expense and amortization of debt issuance costs on our term loan with Goldman Sachs of $2.0 million related to a higher principal balance and interest rate.

Interest expense for 2010 is expected to decrease compared to 2009 due to the repayment in full of our Goldman Sachs term loan in 2009. This anticipated decrease may be offset by additional interest expense in the event new debt financing is obtained.

Loss on debt extinguishment was $3.6 million in 2009 relating to the repayment of our Goldman Sachs term loan. This loss included a prepayment premium of $2.5 million and the recognition of unamortized debt issuance costs of $1.1 million. In 2008, we recognized a loss on debt extinguishment of $0.7 million reflecting the recognition of the unamortized debt issuance costs related to the original Goldman Sachs term loan, upon refinancing of the loan in May of 2008. To conform to the current period presentation, the loss recognized on debt extinguishment in 2008 was reclassified from interest expense as a separate line item. This reclassification had no impact on our previously reported net earnings (losses), financial position or cash flows.

Other income (expense) was $1.8 million in 2009 compared with ($0.1) million in 2008 and ($0.1) million in 2007. The increase in other income in 2009 primarily related to gains of $1.8 million recognized from the revaluation of our warrant liabilities in 2009. See Results of Operations: Warrants Revaluation below for additional disclosure.

Warrants Revaluation

We issued warrants to purchase our common shares in connection with two separate registered direct offerings completed in May and June of 2009. Refer to Liquidity and Capital Resources: Other Equity Financings and Arrangements for additional disclosure relating to these financing transactions.

The warrants issued included a provision allowing for an adjustment of the exercise price and number of warrant shares. This adjustment would occur if we issued or sold certain common shares in the future for a price per share less than the exercise price of the warrants in effect immediately prior to such issuance or sale. Due to this adjustment clause, these warrants were not considered indexed to our stock and were therefore subject to liability and fair value re-measurement.

The fair values of the warrants at the issuance dates were estimated using the Simulation Model, and we recorded liabilities of $2.9 million and $3.6 million for the May and June warrant issuances, respectively. We revalued the warrants quarterly and recorded decreases in the fair value of the warrants of $1.8 million in 2009.

Subsequent to the end of 2009, the warrant holders agreed to amend certain terms of these warrants, as disclosed below in the Subsequent Events section.

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Income Taxes

We recognized $5.7 million in income tax expense in 2009 compared with an income tax benefit of $0.4 million in 2008. Income tax expense in 2009 is primarily related to $5.8 million of foreign income tax expense recognized in connection with the expansion of our existing collaboration with Takeda signed in February of 2009. We were paid a $29 million expansion fee, of which $5.8 million was withheld for payment to the Japanese taxing authority. We also recognized $0.1 million of income tax benefit for 2009 relating to research and development refundable credits, in addition to the $0.4 million in research and development refundable credits recognized in 2008. There was no income tax expense for 2007.

Accounting Standards Codification Topic 740, Income Taxes (“ASC 740”) provides for the recognition of deferred tax assets if realization of such assets is more likely than not. Based upon the weight of available evidence, which includes our historical operating performance and carry-back potential, we have determined that total deferred tax assets should be fully offset by a valuation allowance.

We have recorded cumulative gross deferred tax assets of $189.9 million and $214.7 million at December 31, 2009 and 2008, respectively, principally attributable to the timing of the deduction of certain expenses associated with certain research and development expenses, net operating loss and other carry-forwards. We also recorded corresponding valuation allowances of $189.9 million and $214.7 million at December 31, 2009 and 2008, respectively, to offset these deferred tax assets, as management cannot predict with reasonable certainty that the deferred tax assets to which the valuation allowances relate will be realized.

As of December 31, 2009, we had federal net operating loss carry-forwards of approximately $113 million to offset future taxable income. We also had federal research and development tax credit carry-forwards of approximately $9.4 million. In 2009, we experienced an “ownership change” under Section 382 of the Internal Revenue Code, which subjects the amount of federal and state tax carry-forwards that can be utilized to an annual limitation, which will substantially limit our future use of these carry-forwards per year. To the extent we do not utilize our carry-forwards within the applicable statutory carry-forward periods, either because of Section 382 limitations or the lack of sufficient taxable income, the carry-forwards will expire unused.

We did not have unrecognized tax benefits as of December 31, 2009 and do not expect this to change significantly over the next twelve months. In accordance with ASC 740, we will recognize interest and penalties accrued on any unrecognized tax benefits as a component of income tax expense. As of December 31, 2009, we have not accrued interest or penalties related to uncertain tax positions.

Share-Based Compensation

In February of 2009, our Board of Directors approved a company-wide grant of 4,730,000 share options, of which 4,568,000 were issued as part of our annual incentive compensation package. These options vest monthly over four years and include an acceleration clause based on meeting certain performance measures. In the third quarter of 2009, management determined that it was probable that the performance measures would be achieved. We accelerated expense recognition related to these options, with an estimated implicit service period of twelve months from the grant date, which was subsequently extended an additional twelve months in the fourth quarter of 2009 based on revised assumptions.

In 2009, we recognized $4.4 million in share-based compensation expense, compared with $4.9 million in 2008 and $2.9 million in 2007. The decrease in share-based compensation expense of $0.5 million in 2009, as compared to 2008, was primarily due to a decline in outstanding options as a result of the workforce reduction in January of 2009. Partially offsetting this decrease was the accelerated expense recognition related to the annual grants in February of 2009, as discussed above.

The increase in share-based compensation expense in 2008 of $2.0 million, as compared to 2007, primarily related to the annual grants in October of 2007 and February of 2008 that were subject to shareholder approval, which was obtained in May of 2008, at which point share-based compensation expense was recognized from grant date to approval date.

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As of December 31, 2009, there was $6.8 million of unrecognized share-based compensation expense related to unvested share options with a weighted average remaining recognition period of 2.3 years.

Liquidity and Capital Resources

Cash, cash equivalents and short-term investments at December 31, 2009 were $23.9 million compared with $10.8 million at December 31, 2008. Net cash provided by operating activities was $7.4 million in 2009, compared with net cash used in operating activities of $33.0 million in 2008 and net cash provided by operating activities of $4.5 million in 2007.

The $40.4 million increase in cash provided by operations from 2008 to 2009 was primarily due to the receipt of $23.2 million in the first quarter of 2009 related to the expansion of our existing collaboration with Takeda, the receipt of $22.3 million in the third quarter of 2009 related to the sale of our LUCENTIS^® royalty interest to Genentech and the receipt of $10 million in the second half of 2009 related to two antibody discovery collaboration agreements entered into with Arana and Kaketsuken.

In addition, receivables decreased by $9.5 million in 2009 due to the cessation of LUCENTIS^® and RAPTIVA^® royalty revenue and a decline in contract revenue. The increases in cash were partially offset by a net decrease in the accounts payable and accrued liabilities balance of $2.8 million in 2009 related to the pay down of the accounts payable balance throughout the year and our continued focus on cost control, offset by the accrual of the 2009 employee bonus, restructuring charges and an increase in professional and other fees payable. Also offsetting the increase in cash was a decrease in deferred revenue of $12.2 million in 2009 related to a decline in advance billings and the recognition of the remaining deferred revenue related to upfront fees received for discontinued programs with Merck/Schering-Plough and Takeda.

We expect net cash provided by operating activities to decrease in 2010 due to the expected increase in research and development spending to advance XOMA 052, partially offset by cash generated from our biodefense contracts.

The $37.5 million increase in cash used for operations from 2007 to 2008 included a net loss of $45.2 million offset by non-cash adjustments of $16.1 million, primarily related to depreciation and share-based compensation. In addition, receivables increased by $4.6 million in 2008 primarily related to work performed on the NIAID 3, Novartis, Merck/Schering-Plough and Takeda contracts, offset by a decrease in work performed on the Merck/Schering-Plough/AVEO contract and accrued liabilities decreased by $3.3 million primarily related to the reversal of the 2008 bonus accrual in the fourth quarter when the Company decided it would not pay 2008 bonuses. These decreases in cash were partially offset by an increase in the accounts payable balance of $3.0 million due to the Company paying vendors on longer terms and an increase in other liabilities of $2.1 million related to the NIAID 2 billing adjustment (as detailed above in the Critical Accounting Estimates: Contract Revenue section) for which a credit was provided to the NIH to be applied to future work performed on the NIAID 2 contract.

Cash provided by operations for 2007 consisted of a net loss of $12.3 million offset by non-cash adjustments of $12.4 million, primarily related to depreciation, the revaluation of our embedded derivative and interest paid on our convertible debt, and share-based compensation. In addition, the accounts payable balance increased by $2.8 million and deferred revenue increased by $1.1 million. During 2007, we made payments of $6.6 million for interest on our convertible debt, $3.1 million for interest on our Goldman Sachs term loan, and $1.0 million for our Incentive Plans. In October of 2007, the Board of Directors approved amendments to the Incentive Plans eliminating the provisions requiring payments to be made partly in Common Shares and beginning in 2008, bonuses awarded under the incentive plans are paid entirely in cash.

Net cash provided by investing activities was $10.6 million in 2009, compared with $3.2 million in 2008 and net cash used in investing activities of $8.8 million in 2007. Cash provided by investing activities in 2009

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primarily consisted of a decrease in the restricted cash balance of $9.5 million due to use of the funds for the repayment of our Goldman Sachs term loan in September of 2009. In addition, we received proceeds from maturities of investments of $1.3 million.

Net cash provided by investing activities of $3.2 million in 2008 consisted of net sales and maturities of investments of $14.8 million, partially offset by the transfer to restricted cash of $3.5 million relating to our term loan facility with Goldman Sachs and purchases of fixed assets of $8.1 million, primarily relating to lab and production equipment. Net cash used in investing activities of $8.8 million in 2007 consisted of purchases of fixed assets of $9.5 million and net proceeds from short-term investments of $2.3 million. In addition, $1.7 million was transferred to restricted cash in 2007 related to our term loan facility with Goldman Sachs.

Net cash used in financing activities was $3.6 million for 2009, compared with net cash provided by financing activities of $16.8 million in 2008 and net cash used in financing activities of $1.2 million in 2007. Cash used in financing activities in 2009 related to the repayment in full of the Goldman Sachs term loan, including a principal payment of $8.4 million in the second quarter of 2009, repayment of the remaining outstanding balance of $42 million in September of 2009 and payment of a prepayment premium of $2.5 million, partially offset by proceeds of $49.3 million received from the issuance of common shares in 2009.

Net cash provided by financing activities in 2008 of $16.8 million related to the refinancing of our original loan facility with Goldman Sachs in May of 2008, which netted proceeds of approximately $30.9 million, partially offset by a principal payment of $8.2 million against the outstanding balance of the original facility with Goldman Sachs in the first quarter of 2008. In addition, principal payments of $4.6 million on the new Goldman Sachs facility and $8.9 million on our Novartis note were made in the fourth quarter of 2008. We also received proceeds of $7.6 million from the issuance of common shares related to draws made on our equity line of credit with Azimuth.

Net cash used by financing activities in 2007 of $1.2 million included a $4.7 million principal repayment on our Goldman Sachs term loan, offset by additional borrowings of $2.8 million on our Novartis note and $0.7 million in proceeds received from the issuance of common shares.

Goldman Sachs Term Loan

In September of 2009, we fully repaid our term loan facility with Goldman Sachs, which was a five-year term loan facility originally entered into in November of 2006 and refinanced in May of 2008. Prior to repayment, we were not in compliance with the requirements of the relevant provisions of this loan facility, due to the cessation of royalties from sales of RAPTIVA^® related to its market withdrawal in the first half of 2009. Repayment of this loan facility discharged all of our obligations to the lenders.

We repaid the outstanding principal balance of $42 million, accrued interest to the date of payment of $2.4 million and a prepayment premium of $2.5 million. In the third quarter of 2009, we recorded a loss on repayment of debt of $3.6 million, which included the prepayment premium and the recognition of the unamortized debt issuance costs of $1.1 million. This loss was recorded as loss on debt extinguishment in our consolidated statement of operations for 2009.

Novartis Note

In May of 2005, we executed a secured note agreement with Novartis (then Chiron Corporation), which is due and payable in full in June of 2015. Under the note agreement, we borrowed semi-annually to fund up to 75% of our research and development and commercialization costs under our collaboration arrangement with Novartis, not to exceed $50 million in aggregate principal amount. As of December 31, 2009, the interest rate was 2.44%. At our election, the semi-annual interest payments can be added to the outstanding principal amount, in lieu of a cash payment, as long as the aggregate principal amount does not exceed $50 million and we have made this election for all interest payments thus far. Loans under the note agreement are secured by our interest in the collaboration with Novartis, including any payments owed to us thereunder.

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In November of 2008, we restructured our product development collaboration with Novartis. Pursuant to this restructuring, we will not make any additional borrowings on our Novartis note.

At December 31, 2009, the outstanding principal balance under this note agreement was $13.3 million and for the years ended December 31, 2009, 2008 and 2007 we incurred, and added to the principal balance of the note, interest expense of $0.5 million, $1.2 million and $1.3 million, respectively.

Equity Line of Credit

On October 21, 2008, we entered into a common share purchase agreement (the “Purchase Agreement”) with Azimuth, pursuant to which we obtained a committed equity line of credit facility (the “Facility”) under which we could sell up to $60 million of our registered common shares to Azimuth over a 24-month period, subject to certain conditions and limitations. The Purchase Agreement required a minimum share price of $1.00 per share to allow us to issue shares to Azimuth under the Facility. However, at its election, Azimuth could buy shares below the threshold price at a negotiated discount. We were not obligated to utilize any of the $60 million Facility and remained free to enter other financing transactions. Shares under the Facility were sold pursuant to a prospectus which forms a part of a registration statement declared effective by the Securities and Exchange Commission on May 29, 2008. At the end of the third quarter of 2009, the Facility is no longer in effect, and no additional shares can be issued thereunder.

From the inception of the Facility through 2009, we have sold a total of 42,228,428 common shares to Azimuth for aggregate gross proceeds of $33.9 million. This included the sale of 34.3 million shares in two transactions in September of 2009 that Azimuth agreed to purchase notwithstanding that the purchase prices were below the minimum price of $1.00 required by the Purchase Agreement. We negotiated a discount rate (excluding placement agent fees) of 8.0% for those transactions. Prior to the successful conclusion of negotiations, Azimuth was not obligated to purchase these shares. Offering expenses incurred in 2009 related to sales to Azimuth were $0.4 million.

Other Equity Financings and Arrangements

In May of 2009, we entered into a definitive agreement with an institutional investor to sell 11,764,706 units, with each unit consisting of one of our common shares and a warrant to purchase 0.50 of a common share, for gross proceeds of approximately $10 million, before deducting placement agent fees and estimated offering expenses of $0.8 million, in a registered direct offering. The investor purchased the units at a price of $0.85 per unit. The warrants, which represent the right to acquire an aggregate of up to 5,882,353 common shares, were exercisable at any time on or after May 15, 2009 and prior to May 20, 2014 at an exercise price of $1.02 per share. As of December 31, 2009, all warrants issued in May of 2009 remained outstanding.

In June of 2009, we entered into a definitive agreement with certain institutional investors to sell 10,434,782 units, with each unit consisting of one of our common shares and a warrant to purchase 0.50 of a common share, for gross proceeds of approximately $12 million, before deducting placement agent fees and estimated offering expenses of $0.8 million, in a second registered direct offering. The investor purchased the units at a price of $1.15 per unit. The warrants, which represent the right to acquire an aggregate of up to 5,217,391 common shares, are exercisable at any time on or prior to December 10, 2014 at an exercise price of $1.30 per share. As of December 31, 2009, all warrants issued in June of 2009 remained outstanding.

Subsequent to the end of 2009, the warrant holders agreed to amend certain terms of these warrants and shares were issued on exercise of the warrants issued in May of 2009, as disclosed below in the Subsequent Events section.

In the third quarter of 2009, we entered into the ATM Agreement, with Wm Smith, under which we may sell up to 25 million of our common shares from time to time through Wm Smith, as the agent for the offer and sale of the common shares. Wm Smith may sell these common shares by any method permitted by law deemed to

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be an “at the market” offering as defined in Rule 415 of the Securities Act of 1933, including but not limited to sales made directly on The NASDAQ Global Market, on any other existing trading market for the common shares or to or through a market maker. Wm Smith may also sell the common shares in privately negotiated transactions, subject to our approval. We pay Wm Smith a commission equal to 3% of the gross proceeds of all common shares sold through it as sales agent under the ATM Agreement but in no event less than $0.02 per share. Shares sold under the ATM Agreement are sold pursuant to a prospectus which forms a part of a registration statement declared effective by the Securities and Exchange Commission on May 29, 2008. From the inception of the ATM Agreement through December 31, 2009, we sold a total of 4,050,617 common shares through Wm Smith for aggregate gross proceeds of $2.9 million. Total offering expenses related to these sales were $0.1 million. Refer to the Subsequent Events section below for disclosure regarding the number of shares sold under this agreement subsequent to the end of 2009.

Proceeds from the sale of shares under the equity line of credit, ATM Agreement, registered direct offerings and other equity offerings are being used to continue development of our XOMA 052 product candidate and for other working capital and general corporate purposes. We also used the proceeds to repay the Goldman Sachs term loan in September of 2009.

Convertible Debt

In February of 2006, we completed an exchange offer with holders of our 6.5% convertible senior notes due 2012 in which we exchanged $60 million aggregate principal amount of 6.5% Convertible SNAPs_SM due 2012 (the “New Notes”) for all $60 million aggregate principal amount of our then outstanding convertible senior notes due 2012. We also issued an additional $12 million of New Notes to the public for cash at a public offering price of 104% of principal, or $12.5 million.

In the first quarter of 2007, holders voluntarily converted $42 million of our New Notes and we converted the $2.5 million of our New Notes that remained outstanding (the other $27.5 million thereof having been converted in 2006). As a result, 25,640,187 shares were issued to effect the conversion of the principal balances. Additionally, at the time of conversion, we issued 1,889,317 shares and $5.2 million in cash to satisfy the remaining additional interest payment feature related to these converted notes.

For the year ended December 31, 2007, we incurred $0.2 million in interest expense related to our convertible debt, amortized $0.1 million in debt issuance costs, premium and discount, and recognized $6.1 million in interest expense related to the revaluation of the embedded derivative.

*            *            *

We have incurred significant operating losses and negative cash flows from operations since our inception. At December 31, 2009, we had cash and cash equivalents of $23.9 million. During 2010, we expect to continue using our cash and cash equivalents to fund ongoing operations. Additional licensing, antibody discovery and development collaboration agreements, government funding and financing arrangements may positively impact our cash balances. Based on our cash reserves and anticipated spending levels, revenue from collaborations including a XOMA 052 corporate partnership, licensing transactions or biodefense contracts and other sources of funding we believe to be available, we estimate that we have sufficient cash resources to meet our anticipated net cash needs through the next twelve months. Any significant revenue shortfalls, increases in planned spending on development programs or more rapid progress of development programs than anticipated, as well as the unavailability of anticipated sources of funding, could shorten this period. If adequate funds are not available, we will be required to delay, reduce the scope of, or eliminate one or more of our product development programs and further reduce personnel-related costs. Progress or setbacks by potentially competing products may also affect our ability to raise new funding on acceptable terms.

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Commitments and Contingencies

Schedule of Contractual Obligations

Payments by period due under contractual obligations at December 31, 2009 are as follows (in thousands):

In addition to the above, we have committed to make potential future “milestone” payments to third parties as part of licensing and development programs. Payments under these agreements become due and payable only upon the achievement of certain developmental, regulatory and/or commercial milestones. Because it is uncertain if and when these milestones will be achieved, such contingencies, aggregating up to $79 million have not been recorded on our consolidated balance sheet. We are also obligated to pay royalties, ranging generally from 1.5% to 5% of the selling price of the licensed component and up to 40% of any sublicense fees to various universities and other research institutions based on future sales or licensing of products that incorporate certain products and technologies developed by those institutions. We are unable to determine precisely when and if our payment obligations under the agreements will become due as these obligations are based on future events, the achievement of which is subject to a significant number of risks and uncertainties.

Although operations are influenced by general economic conditions, we do not believe that inflation had a material impact on financial results for the periods presented. We believe that we are not dependent on materials or other resources that would be significantly impacted by inflation or changing economic conditions in the foreseeable future.

Recent Accounting Pronouncements

In June of 2009, the Financial Accounting Standards Board (“FASB”) established the FASB Accounting Standards Codification (the “ASC”) as the source of authoritative accounting principles recognized by the FASB. The FASB will issue new standards in the form of Accounting Standards Updates (“ASU”). The ASC is effective for financial statements issued for interim and annual periods ending after September 15, 2009 and therefore was effective for us in the third quarter of 2009. The issuance of the ASC does not change U.S. generally accepted accounting principles (“GAAP”) and therefore the adoption of the ASC only affects the specific references to GAAP literature in the notes to our consolidated financial statements.

Accounting Standards Codification Topic 855, Subsequent Events (“ASC 855”) establishes general standards of accounting for and disclosure of events that occur after the balance sheet date but before financial statements are issued. In particular, ASC 855 sets forth the period after the balance sheet date during which management should evaluate events or transactions that may occur for potential recognition or disclosure in the financial statements, the circumstances under which an entity should recognize events or transactions occurring after the balance sheet date in its financial statements, and the disclosures that an entity should make about events or transactions that occurred after the balance sheet date. The new provisions of ASC 855 were effective for interim financial reporting periods ending after June 15, 2009 and did not have a material effect on our financial statements.

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Accounting Standards Codification Topic 320, Investments—Debt and Equity Securities (“ASC 320”) contains an amendment to make previous guidance regarding other-than-temporary impairments more operational and to improve the presentation of other-than-temporary impairments in the financial statements. This amendment replaces the existing requirement that management assert it has both the intent and ability to hold an impaired debt security until recovery with a requirement that management assert it does not have the intent to sell the security and it is more likely than not it will not have to sell the security before recovery of its cost basis. ASC 320 requires increased and more frequent disclosures regarding expected cash flows, credit losses, and an aging of securities with unrealized losses. The amended provisions of ASC 320 were effective for interim financial reporting periods ending after April 1, 2009 and did not have a material effect on our financial statements.

Accounting Standards Codification Topic 808, Collaborative Arrangements (“ASC 808”) defines collaborative arrangements and establishes reporting requirements for transactions between participants and third parties in a collaborative arrangement. ASC 808 prohibits companies from applying the equity method of accounting to activities performed outside a separate legal entity by a virtual joint venture. Instead, revenue and costs incurred with third parties in connection with the collaborative arrangement should be presented gross or net by the collaborators based on the criteria in Accounting Standards Codification Topic 605, Revenue Recognition (“ASC 605”), and other applicable accounting literature. The new provisions of ASC 808 should be applied to collaborative arrangements in existence at the date of adoption using a modified retrospective method that requires reclassification in all periods presented for those arrangements still in effect at the transition date, unless that application is impracticable. Effective January 1, 2009 we adopted the new provisions of ASC 808, which did not have a material effect on our financial statements. As a result of the restructuring in November of 2008 of our collaboration agreement with Novartis, this collaboration agreement is no longer within the scope of ASC 808. As of December 31, 2009, we do not have any collaboration agreements that fall under the scope of ASC 808.

Accounting Standards Codification Topic 815, Derivatives and Hedging (“ASC 815”) clarifies how to determine whether certain instruments or features are indexed to an entity’s own stock. This provision of ASC 815 applies to any free standing financial instrument or embedded feature that has all the characteristics of a derivative, as defined in ASC 815. Effective January 1, 2009, we adopted the relevant provisions of ASC 815. Refer to the Critical Accounting Estimates—Warrant Liabilities section above for the effect this adoption had on our financial statements.

Accounting Standards Codification Topic 820, Fair Value Measurements and Disclosures (“ASC 820”) defines fair value and establishes a framework for measuring the fair value of financial assets and liabilities. Effective January 1, 2009, we adopted the provisions of ASC 820, as it relates to non-financial assets and non-financial liabilities, which did not have a material effect on our financial statements.

Accounting Standards Update No. 2009-13, Revenue Recognition Topic 605: Multiple Deliverable Revenue Arrangements—A Consensus of the FASB Emerging Issues Task Force provides application guidance on whether multiple deliverables exist, how the deliverables should be separated and how the consideration should be allocated to one or more units of accounting. This update establishes a selling price hierarchy for determining the selling price of a deliverable. The selling price used for each deliverable will be based on vendor-specific objective evidence, if available, third-party evidence if vendor-specific objective evidence is not available, or estimated selling price if neither vendor-specific or third-party evidence is available. We will adopt this guidance from January 1, 2011. We are assessing the impact of this guidance on our consolidated results of operations and financial condition.

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Subsequent Events

Underwritten Offering

On February 2, 2010, we entered into an underwritten offering with investors to sell 42 million units, with each unit consisting of one of our common shares and a warrant to purchase 0.45 of a common share, for gross proceeds of approximately $21 million, before deducting underwriting discounts and commissions and estimated offering expenses of $1.7 million. The investors purchased the units at a price of $0.50 per unit. The warrants, which represent the right to acquire an aggregate of up to 18.9 million common shares, are exercisable beginning six months and one day after issuance and have a five-year term and an exercise price of $0.70 per share.

Warrant Amendments and Exercises

Also on February 2, 2010, we agreed to amend the terms of the warrants issued in May and June of 2009 to eliminate the provisions that would have required reduction of the warrant exercise price and an increase in the number of shares issuable on exercise of the warrants each time we sold common shares at a price less than the exercise price of such warrants. In return, the exercise price of the warrants issued in May of 2009 was reduced to from $1.02 per share to $0.001 per share and we made a $4.5 million payment to holders of the warrants issued in June of 2009. The exercise price of the warrants issued in June of 2009 remains unchanged at $1.30 per share. In February of 2010, the holders of warrants issued in May of 2009 exercised warrants to acquire 5,882,353 common shares for an aggregate exercise price of $5,882, and as a result no warrants issued in May of 2009 remain outstanding.

Common Shares Sold Under the ATM Agreement

Subsequent to December 31, 2009, we sold an additional 8,940,225 common shares through Wm Smith for aggregate gross proceeds of $6.4 million. Total offering expenses related to these sales were $0.2 million.

Forward-Looking Information and Cautionary Factors That May Affect Future Results

Certain statements contained herein related to the sufficiency of our cash resources and our efforts to enter into a collaborative arrangement with respect to XOMA 052, as well as other statements related to current plans for product development and existing and potential collaborative and licensing relationships, or that otherwise relate to future periods, are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. These statements are based on assumptions that may not prove accurate. Actual results could differ materially from those anticipated due to certain risks inherent in the biotechnology industry and for companies engaged in the development of new products in a regulated market. Among other things, the period for which our cash resources are sufficient could be shortened if expenditures are made earlier or in larger amounts than anticipated or are unanticipated, if anticipated revenue or cost sharing arrangements do not materialize, or if funds are not otherwise available on acceptable terms; and, we may not be able to enter into a collaborative arrangement with respect to XOMA 052 on acceptable terms within the timeframes anticipated or at all. These and other risks, including those related to inability to comply with NASDAQ’s continued listing requirements; the generally unstable nature of current economic conditions; the results of discovery research and preclinical testing; the timing or results of pending and future clinical trials (including the design and progress of clinical trials; safety and efficacy of the products being tested; action, inaction or delay by the FDA, European or other regulators or their advisory bodies; and analysis or interpretation by, or submission to, these entities or others of scientific data); changes in the status of existing collaborative relationships; the ability of collaborators and other partners to meet their obligations; our ability to meet the demand of the United States government agency with which we have entered our government contracts; competition; market demands for products; scale-up and marketing capabilities; availability of additional licensing or collaboration opportunities; international operations; share price volatility; our financing needs and opportunities; uncertainties regarding the status of biotechnology patents; uncertainties as to the costs of protecting intellectual property; and risks associated with our status as a Bermuda company, are described in more detail in Item 1A: Risk Factors.

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Interest Rate Risk

Our exposure to market rate risk for changes in interest rates relates primarily to our investment portfolio and our loan facility. By policy, we make our investments in high quality debt securities, limit the amount of credit exposure to any one issuer and limit duration by restricting the term of the instrument. We generally hold investments to maturity, with a weighted average portfolio period of less than twelve months. However, if the need arose to liquidate such securities before maturity, we may experience losses on liquidation. We do not invest in derivative financial instruments.

We hold interest-bearing instruments that are classified as cash, cash equivalents and short-term investments. Fluctuations in interest rates can affect the principal values and yields of fixed income investments. If interest rates in the general economy were to rise rapidly in a short period of time, our fixed income investments could lose value.

The following table presents the amounts and related weighted average interest rates of our cash and investments at December 31, 2009 and 2008 (in thousands, except interest rate):

As of December 31, 2009, we have an outstanding principal balance on our note with Novartis of $13.3 million, which is due in 2015. The interest rate on this note is charged at a rate of USD six-month LIBOR plus 2%, which was 2.44% at December 31, 2009. No further borrowing is available under this facility.

The variable interest rate related to our long-term debt instrument is based on LIBOR. We estimate that a hypothetical 100 basis point change in interest rates could increase or decrease our interest expense by approximately $0.1 million on an annualized basis.

The following consolidated financial statements of the registrant, related notes and report of independent registered public accounting firm are set forth beginning on page F-1 of this report.

Not applicable.

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Under the supervision and with the participation of our management, including our Chairman, Chief Executive Officer and President and our Vice President, Finance and Chief Financial Officer, we conducted an evaluation of our disclosure controls and procedures, as such term is defined under Rule 13a-15(e) promulgated under the Securities Exchange Act of 1934, as amended, as of the end of the period covered by this report. Our disclosure controls and procedures are intended to ensure that the information we are required to disclose in the reports that we file or submit under the Securities Exchange Act of 1934 is (i) recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission’s rules and forms and (ii) accumulated and communicated to our management, including the Chairman, Chief Executive Officer and President and Vice President, Finance and Chief Financial Officer, as the principal executive and financial officers, respectively, to allow timely decisions regarding required disclosures. Based on this evaluation, our Chairman, Chief Executive Officer and President and our Vice President, Finance and Chief Financial Officer concluded that our disclosure controls and procedures were effective as of the end of the period covered by this report.

We continue to enhance internal financial controls and staffing consistent with the requirements of the Sarbanes-Oxley Act of 2002. Apart from this, there were no changes in our internal controls over financial reporting during 2009 that have materially affected, or are reasonably likely to materially affect, our internal controls over financial accounting.

Management’s Report on Internal Control over Financial Reporting

Management, including our Chairman, Chief Executive Officer and President and our Vice President, Finance and Chief Financial Officer, is responsible for establishing and maintaining adequate internal control over financial reporting (as such term is defined in Exchange Act Rules 13a-159f). The Company’s internal control system was designed to provide reasonable assurance to the Company’s management and board of directors regarding the preparation and fair presentation of published financial statements in accordance with accounting principles generally accepted in the United States.

Management assessed the effectiveness of our internal control over financial reporting as of December 31, 2009. In making this assessment, management used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (COSO) in Internal Control—Integrated Framework. Based on our assessment we believe that, as of December 31, 2009, our internal control over financial reporting is effective based on those criteria.

The Company’s internal control over financial reporting as of December 31, 2009, has been audited by Ernst & Young, LLP, the independent registered public accounting firm who also audited the Company’s consolidated financial statements. Ernst & Young’s attestation report on the Company’s internal control over financial reporting follows.

Changes in Internal Control over Financial Reporting

Our management, including our Chairman, Chief Executive Officer and President and our Vice President, Finance and Chief Financial Officer, has evaluated any changes in our internal control over financial reporting that occurred during the quarter ended December 31, 2009, and has concluded that there was no change during such quarter that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

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REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Board of Directors and Shareholders of XOMA Ltd.:

We have audited XOMA Ltd.’s internal control over financial reporting as of December 31, 2009, based on criteria established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (the COSO criteria). XOMA Ltd.’s management is responsible for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting included in the accompanying Management’s Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the company’s internal control over financial reporting based on our audit.

We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

In our opinion, XOMA Ltd. maintained, in all material respects, effective internal control over financial reporting as of December 31, 2009, based on the COSO criteria.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States), the consolidated balance sheets of XOMA Ltd. as of December 31, 2009 and 2008 and the related consolidated statements of operations, shareholders’ equity (net capital deficiency) and cash flows for each of the three years in the period ended December 31, 2009, and our report dated March 11, 2010 expressed an unqualified opinion thereon.

/s/ ERNST & YOUNG LLP

San Francisco, California

March 11, 2010