Results From Two Phase 2 Studies in XOMA's Gevokizumab Proof-of-Concept Program Are Very Encouraging and Compelling

• Three-month results from erosive osteoarthritis of the hand study are very encouraging, and full six-month data will determine potential Phase 3 program
• Pyoderma gangrenosum selected as next indication for Pivotal clinical development based on compelling results
• Company to host webcast slide presentation at 5:30 p.m. ET / 2:30 p.m. PT today

BERKELEY, Calif., Oct. 30, 2013 (GLOBE NEWSWIRE) -- XOMA Corporation (Nasdaq:XOMA), a leader in the discovery and development of therapeutic antibodies, today announced very encouraging results from two Phase 2 clinical studies that are part of the Company's broad gevokizumab proof-of-concept ("POC") program.

Erosive Osteoarthritis of the Hand Phase 2 POC Study

The Phase 2 POC study in erosive osteoarthritis of the hand ("EOA") patients with elevated C-reactive protein ("CRP") levels greater than or equal to 2.5 mg/L is a double-blind, placebo-controlled study to determine if gevokizumab can improve the pain, stiffness, and physical function associated with EOA after three and six months of treatment, based upon the Australian/Canadian Osteoarthritis Hand Index ("AUSCAN™") scoring scale. AUSCAN is a validated self-administered questionnaire specifically designed to assess the three dimensions of pain, disability, and joint stiffness of osteoarthritis of the hand using a series of 15 questions. XOMA's study enrolled 85 EOA patients who were randomized 2:1 to receive 60 mg of gevokizumab or placebo, dosed subcutaneously once monthly.

In this study, the percent change in AUSCAN score is measured from baseline on a monthly basis, with efficacy assessments calculated at Day 84 and Day 168. The Day 84 results demonstrate gevokizumab-treated patients experienced a greater lowering in their mean AUSCAN score than patients in the placebo-treated group. After three months of treatment, patients who received gevokizumab (n=57) demonstrated a 23 percent reduction from baseline in the composite AUSCAN score compared to a 14 percent reduction in placebo arm patients (n=28). In addition to AUSCAN score, Day 84 and Day 168 endpoints also include radiographic images to assess the potential change in joint damage from baseline.

The study will continue on a blinded basis until all patients receive the full six months of treatment. Upon completion of the study, including the analysis of radiographic images of the affected joints, and the conclusion of the supplemental study in patients with CRP less than 2.5 mg/L, both of which are expected to occur in the first quarter of 2014, XOMA will determine the requirements for a potential Phase 3 program based on advisory and regulatory input.

"Data from this trial has allowed us to determine that a pivotal study would require around 230 patients in each arm in order to achieve statistical significance at the same magnitude of effect we saw at three months.  If the improvement in response trends we have observed continue, the six-month endpoint, which is the accepted primary endpoint for studies in arthritis, should require even fewer subjects per arm," said Paul Rubin Senior Vice President, Research and Development and Chief Medical Officer of XOMA.  "It also is very encouraging that all the best responders, as measured by all components of the AUSCAN, in this trial were treated with gevokizumab. We hope our efforts lead to gevokizumab becoming an important therapeutic option for these underserved patients."

Pyoderma Gangrenosum Pilot Study

XOMA also provided the first data from its pilot study in pyoderma gangrenosum ("PG").  The Company's pilot study was designed to enroll up to eight patients who are experiencing acute inflammatory PG, evaluate the response in the first four patients, and be able to make decisions to continue the study with a higher dosing regimen The first four PG patients enrolled in Company's pilot program have provided compelling data on gevokizumab's potential to treat this rare ulcerative skin disease.  These patients receive 60 mg gevokizumab dosed once monthly for three months.  The outcome measure is Improvement in Investigator's Assessment of the target PG ulcer.  Of the four patients, three showed improvement of ulcer size by Day 28. One patient had total resolution of the ulcer by Day 84, while a second patient had 93% improvement in ulcer size by Day 56. Additionally, all patients have articulated an improvement in their pain levels.  Based upon the persuasive nature of these results, XOMA has chosen not to enroll patients in the higher dose cohort.

In tandem, XOMA announced two patients with a related disease, generalized pustular psoriasis ("GPP"), who have received gevokizumab under a compassionate use protocol have seen significant improvement in their diseases.  PG and GPP are two diseases that are classified as neutrophilic dermatoses, which are a group of non-infectious inflammatory dermatologic conditions that have neutrophil involvement. The Company will request a meeting with the U.S. Food and Drug Administration ("FDA") to review the data and discuss the requirements to move gevokizumab into a pivotal Phase 3 program in PG.

"Pyoderma gangrenosum is a serious, highly debilitating, very rare disease with limited therapeutic options and high unmet need.  We initiated our POC trial based on discussions with FDA and a general understanding on the potential abbreviated path to approval for this indication," stated John Varian, Chief Executive Officer of XOMA.  "Based upon these early compelling results, we will discuss with the FDA the details for accelerated development with a single pivotal trial, typical in these types of rare diseases, to form the basis for a BLA filing."

Gevokizumab was generally well tolerated, and there were no drug-related serious adverse events reported in the studies.  In the EOA study, the most common adverse events were headache, pain, urinary tract infections and pneumonia and they were comparable between gevokizumab and placebo. In the open-label studies, patients reported mild to moderate headache, nausea, diarrhea, chest congestion, and secondary skin infections, all of which resolved with treatment and one case of unrelated ongoing exfoliative dermatitis following antibiotic treatment.

Investor Conference Call and Webcast

XOMA will host a webcast with data slides today, October 30, 2013, at 5:30 p.m. ET / 2:30 p.m. PT. The webcast can be accessed via the Investors and Media section of XOMA's website at http://investors.xoma.com/events.cfm and will be available for replay until close of business on November 4, 2013. 

Telephone numbers for the live audiocast are 877-369-6589 (U.S./Canada) and 408-337-0122 (international).

About Gevokizumab

Gevokizumab is a potent monoclonal antibody with unique allosteric modulating properties and the potential to treat patients with a wide variety of inflammatory and other diseases. Gevokizumab binds strongly to interleukin-1 beta (IL-1 beta), a pro-inflammatory cytokine, and modulates the cellular signaling events that produce inflammation. IL-1 beta has been shown to be involved in diverse array of disease states, including non-infectious uveitis (including Behçet's uveitis), cardiovascular disease, and other auto-inflammatory diseases. 

Gevokizumab currently is being studied in a global Phase 3 clinical program, termed EYEGUARD™, which is being conducted by SERVIER and XOMA. This program is designed to determine gevokizumab's ability to treat acute non-infectious uveitis (NIU) in EYEGUARD-A, to prevent disease flares in patients with Behçet's uveitis in EYEGUARD-B, and to prevent disease flares in NIU patients who are controlled with steroids and immunosuppressants in EYEGUARD-C.

XOMA has a Proof-of-Concept (POC) program underway in which the Company is exploring the efficacy and safety of gevokizumab in multiple indications. The Company reported promising data in January 2013 from the interim analysis of a Phase 2 study in moderate to severe inflammatory acne. Data from the National Eye Institute's study of gevokizumab in patients with active non-infectious anterior scleritis is expected later this year. XOMA anticipates full results from its two POC studies in patients with erosive osteoarthritis of the hand in the first quarter of 2014. Separately, SERVIER initiated a Phase 2 study to determine gevokizumab's ability to reduce arterial wall inflammation in patients with marked atherosclerotic plaque inflammation and who have experienced an acute coronary syndrome in the previous twelve months, as well as a POC study in polymyositis/dermatomyositis. Information about gevokizumab clinical studies can be found at www.clinicaltrials.gov and www.clinicaltrialsregister.eu.

About Erosive Osteoarthritis of the Hand

Erosive osteoarthritis of the hand (EOA) is caused by the breakdown of the body's natural balance between cartilage formation and degradation, which leads to the narrowing of the space between the first and second joints in the fingers. Patients with EOA experience high degrees of pain, including throbbing, swelling, and prolonged periods of morning stiffness. Over time, the joints become deformed, impacting hand function and ultimately reducing EOA patients' quality of life. Approximately four million people in the U.S. have been diagnosed with EOA, and the disease affects women twelve times more often than men for reasons that are not understood by the scientific or medical community.

XOMA believes gevokizumab may be able to reduce the symptoms associated with EOA by modulating IL-1β levels. EOA is the second indication in XOMA's gevokizumab Phase 2 proof-of-concept program. 

About Neutrophilic Dermatoses

Neutrophilic dermatoses are a group of conditions that are characterized by skin lesions that have intense epidermal and/or dermal inflammatory infiltrates, primarily neutrophils, with no evidence of infection. They are classified based upon their individual clinical and pathologic features, as well as the identification of underlying diseases that are associated with neutrophilic dermatoses. Neutrophilic dermatoses can present as vesiculopustules (blisters), plaques (superficial, solid, elevated skin lesions), nodules (a small mass of tissue that protrudes or a knot that can be felt), or ulcers, and the lesions may be localized or cover a large area of the body. The causes of neutrophilic dermatoses are unknown, but patients may be experiencing an immunologic reaction. Most neutrophilic dermatoses are treated with systemic corticosteroids and other immunomodulators.

About Pyoderma Gangrenosum

Pyoderma gangrenosum ("PG") is a rare neutrophilic dermatosis of painful expanding necrotic skin ulcers, which has four classifications based upon the type of skin ulcers manifested. Both the U.S. National Organization for Rare Diseases ("NORD") and The European Organization Orphanet list pyoderma gangrenosum in their rare disease databases.  Orphanet states the prevalence as unknown but provides an incidence range between 1 and 3.3 per 330,000.   The U.S. Department of Health and Human Services' National Institutes of Health's Office of Rare Disease Research lists PG occurring in about 1 per 100,000 people. Approximately 50 to 70 percent of the PG patient population has an underlying systemic condition, while the remainder is idiopathic (unknown cause). The most prevalent underlying condition is inflammatory bowel disease ("IBD"), most commonly ulcerative colitis and Crohn's disease. The prognosis for PG is directly linked to the patient's response to therapy for the underlying disease. Patients receive a combination of topical and systemic therapy to treat the ulcers, which may take up to two years to heal. Despite the ongoing use of systemic therapy, up to 46 percent of patients experience a relapse.

About Generalized Pustular Psoriasis

Generalized pustular psoriasis ("GPP") is a rare acute, chronic, or relapsing neutrophilic dermatosis. Chronic and relapsing disease typically are characterized by episodes of fever and tremors, which are accompanied by the immediate appearance on the skin of non-infectious pustules that merge to become larger clusters of pus, dry, and peel off in sheets. These episodes may take weeks to resolve, and after an episode, the patient may be left with significant scaling of the affected areas. Patients who experience GPP may have localized disease, or the disease may affect the majority of their bodies, and one form, named von Zumbusch pustular psoriasis, may be life-threatening. There are approximately 2,500 new cases of GPP diagnosed annually in the United States. 

About XOMA

XOMA has built a portfolio of innovative therapeutic antibodies, both in late-stage clinical development and in preclinical research. XOMA focuses its antibody research and development on allosteric modulation, which offers opportunities for new classes of therapeutic antibodies to treat a wide range of human diseases. XOMA's lead product candidate, gevokizumab (IL-1 beta modulating antibody), is in a global Phase 3 program in non-infectious uveitis with its partner SERVIER and multiple proof-of-concept studies in other IL-1-mediated diseases. XOMA's scientific research also produced the XMet program, which consists of three classes of preclinical antibodies, including Selective Insulin Receptor Modulators (SIRMs) that could have a major effect on the treatment of diabetes.

More detailed information can be found at www.xoma.com.

About SERVIER

SERVIER is a privately run French research-based pharmaceutical company. Current therapeutic domains for SERVIER medicines are cardiovascular, metabolic, neurological, psychiatric and bone and joint diseases, as well as oncology. SERVIER is established in 140 countries worldwide with over 20,000 employees and a 2012 turnover of €3.9 billion. SERVIER invests 25% of its turnover in R&D.

More information is available at www.servier.com.

Forward-Looking Statements

Certain statements contained in this press release including, but not limited to, statements related to anticipated timing of initiation and completion of clinical trials and proof-of-concept trials, anticipated size of clinical trials, continued sales of approved products, sufficiency of our cash resources and anticipated levels of cash utilization, 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, and 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. Potential risks to XOMA meeting these expectations are described in more detail in XOMA's most recent filing on Form 10-K and in other SEC filings. Consider such risks carefully when considering XOMA's prospects. Any forward-looking statement in this press release represents XOMA's views only as of the date of this press release and should not be relied upon as representing its views as of any subsequent date. XOMA disclaims any obligation to update any forward-looking statement, except as required by applicable law.

CONTACT: XOMA Corporation

         Company and Investor Contact:
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         Media Contact:
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Released October 30, 2013