XOMA Presents First XOMA 052 Cardiovascular Disease Animal Model Results

Company Also Presents Results of U.S. Phase 1 XOMA 052 Clinical Trial in Type 2 Diabetes at International Medical Meeting

BERKELEY, Calif., Oct. 20, 2009 (GLOBE NEWSWIRE) -- XOMA Ltd. (Nasdaq:XOMA), a leader in the discovery and development of therapeutic antibodies, announced the presentation today of peer-reviewed results with XOMA 052, its antibody to interleukin-1 beta (IL-1 beta), at two international conferences.

Preclinical results with XOMA 052 in an animal model of cardiovascular disease were presented today at the 2009 Annual Meeting of the Society for Leukocyte Biology, International Cytokine Society, & International Society for Interferon and Cytokine Research (Tri-Society) in Lisbon, Portugal. The presentation, entitled "XOMA 052, a regulatory monoclonal antibody targeting IL-1 beta, reduces biomarkers of cardiovascular risk in animal models," included results of studies in the apolipoprotein E (ApoE) knockout mouse model, a well-validated model of atherosclerosis that follows a similar pattern of progression to that of atherosclerosis in humans.

The results demonstrated that mice treated with a murine equivalent of XOMA 052 had a statistically significant reduction in the formation of atherosclerotic lesions, also known as plaque, in the aorta (p<0.05), and trends toward improved lipid profiles, compared to mice receiving a control antibody. Results from this study and XOMA 052 animal model studies in the diet-induced obesity model are available via the home page of the XOMA web site, www.xoma.com; click on "download here" link below "Tri-Society Presentation."

"These new results demonstrate for the first time that XOMA 052 has a direct, beneficial effect on plaque build-up in an established animal model of cardiovascular disease," said Stephen Doberstein, Ph.D., XOMA's Vice President of Research. "We are currently evaluating XOMA 052 in animal models of acute and chronic cardiovascular disease and anticipate these results will provide further support for our XOMA 052 development program."

Additionally, the company presented the results of its U.S. Phase 1 clinical trial of XOMA 052 in Type 2 diabetes at the International Diabetes Federation's (IDF) World Diabetes Conference in Montreal, Canada in a poster presentation entitled "XOMA 052, a potential disease-modifying anti-interleukin-1 beta (IL-1 beta) regulatory antibody, shows reductions in hs-CRP, HbA1c and FPG after subcutaneous injection in a randomized, blinded, placebo-controlled trial in subjects with type 2 diabetes." Results from this trial were announced on July 14 and are available via the home page of the XOMA website, www.xoma.com; click on the "download here" link below "XOMA 052 Phase 1 Results." These results support initiation of the Phase 2 clinical development program in diabetes and cardiovascular disease.

About XOMA 052

XOMA 052 is a potent monoclonal antibody with the potential to improve the treatment of patients with a wide variety of inflammatory diseases. XOMA 052 binds strongly to IL-1 beta, a pro-inflammatory cytokine involved in the development of Type 2 diabetes, cardiovascular disease, rheumatoid arthritis, gout and other diseases. By binding to IL-1 beta, XOMA 052 inhibits the activation of the IL-1 receptor, thereby preventing the cellular signaling events that produce inflammation. XOMA 052 has a half-life of 22 days. Based on its binding properties, specificity to IL-1 beta and half-life, XOMA 052 may provide convenient dosing of once per month or less frequently.

XOMA developed XOMA 052 using the company's proprietary antibody technologies, capabilities and expertise. XOMA owns worldwide rights to the antibody and related intellectual property. The company is actively pursuing a partnership for the development and commercialization of XOMA 052.

About XOMA

XOMA discovers, develops and manufactures novel antibody therapeutics. The company's proprietary product pipeline includes XOMA 052, an anti-IL-1 beta antibody, and XOMA 3AB, a biodefense anti-botulism antibody candidate, and a preclinical pipeline with candidates in development for inflammatory, autoimmune, infectious and oncological diseases. In addition to its proprietary pipeline, XOMA develops products with premier pharmaceutical companies including Novartis AG, Schering-Plough Research Institute and Takeda Pharmaceutical Company Limited.

XOMA has multiple revenue streams resulting from the licensing of its antibody technologies, product royalties, development collaborations and biodefense contracts. XOMA's technologies have contributed to the success of marketed antibody products, including LUCENTIS(r) (ranibizumab injection) for wet age-related macular degeneration and CIMZIA(r) (certolizumab pegol) for rheumatoid arthritis and Crohn's disease.

The company has a premier antibody discovery and development platform that incorporates an unmatched collection of antibody phage display libraries and proprietary Human Engineering(tm) and Bacterial Cell Expression (BCE) and manufacturing technologies. BCE is a key breakthrough biotechnology for the discovery and manufacturing of antibodies and other proteins. As a result, more than 50 pharmaceutical and biotechnology companies have signed BCE licenses, and several licensed product candidates are in clinical development.

XOMA has a fully integrated product development infrastructure, extending from pre-clinical science to approval, and a team of about 200 employees at its Berkeley, California location. For more information, please visit http://www.xoma.com.

The XOMA Ltd. logo is available at https://www.globenewswire.com/newsroom/prs/?pkgid=5960

Forward-Looking Statements

Certain statements contained herein concerning product development 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.

These risks, including those related to inability to comply with NASDAQ's continued listing requirements, the declining and generally unstable nature of current economic conditions; the results of discovery and pre-clinical 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; XOMA's ability to meet the demands of the United States government agency with which it has entered into its government contracts; competition; market demands for products; scale-up and marketing capabilities; availability of additional licensing or collaboration opportunities; international operations; share price volatility; XOMA's financing needs and opportunities; uncertainties regarding the status of biotechnology patents; uncertainties as to the costs of protecting intellectual property; and risks associated with XOMA's status as a Bermuda company, 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.

CONTACT:  XOMA
          Investor Contact:
          Carol DeGuzman
          510-204-7270
          deguzman@xoma.com

          Porter Novelli Life Sciences
          Media Contact:
          Carolyn Hawley
          619-849-5375
          chawley@pnlifesciences.com

Released October 20, 2009