XOMA 052 Shows Potent In Vitro Inhibition of Interleukin-6 Production in Human Myeloma Cells

BERKELEY, Calif., April 19, 2010 (GLOBE NEWSWIRE) -- XOMA Ltd. (Nasdaq:XOMA), a leader in the discovery and development of therapeutic antibodies, announced that independent researchers today presented results showing that XOMA's antibody to interleukin-1 beta (IL-1 beta), XOMA 052, was highly effective in reducing production of a protein that supports the proliferation of cancerous human myeloma cells in vitro. These results are consistent with a 47 patient clinical trial in early-stage myeloma patients which demonstrated that IL-1 blockade with IL-1 receptor antagonist Kineret(R) (anakinra) in combination with standard therapy improved progression-free survival. The new data were presented at the 101st Annual Meeting of the American Association of Cancer Research (AACR) (Abstract # 2449).

IL-1 beta stimulates the production of interleukin-6 (IL-6), a protein that is a potent growth factor for myeloma cells. XOMA 052 is a high affinity antibody that inhibits IL-1 beta activity. The results presented at the AACR meeting indicated that XOMA 052 reduced IL-1 beta-induced IL-6 production in the myeloma patient samples by more than 85%, which was superior to the effects of the anti-inflammatory drug dexamethasone commonly used to treat myeloma. The reduction with XOMA 052 was greater than 90% in samples from the patients with the highest levels of IL-6 production. The researchers concluded that treatment with an antibody such as XOMA 052 in combination with standard therapy may be useful in myeloma patients who demonstrate elevated IL-6 levels.

"These results provide another example of the broad clinical potential for IL-1 beta targeting with XOMA 052" said Steven B. Engle, XOMA's Chairman and Chief Executive Officer. "While the focus of our current XOMA 052 clinical development program is on diabetes and cardiovascular disease, we are pleased that results such as those presented today provide additional avenues for exploration through collaborations at leading research and clinical institutions."

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.

About XOMA

XOMA discovers, develops and manufactures novel antibody therapeutics for its own proprietary pipeline as well as through license and collaborative agreements with pharmaceutical and biotechnology companies, and under its contracts with the U.S. government. The company's proprietary product pipeline includes:

  --  XOMA 052, an anti-IL-1 beta antibody in Phase 2 clinical development for
      Type 2 diabetes, Type 1 diabetes and cardiovascular disease, with
      potential for the treatment of a wide range of inflammatory
      conditions.

  --  XOMA 3AB, an antibody candidate in pre-IND studies to neutralize the
      botulinum toxin, among the most deadly potential bioterror threats,
      under development through funding provided by the National Institute of
      Allergy and Infectious Diseases of the National Institutes of Health
      (Contract # HHSN266200600008C).

  --  A preclinical pipeline with candidates in development for several
      diseases.

In addition to its proprietary pipeline, XOMA develops products with premier pharmaceutical companies including Novartis AG, Schering Corporation, a subsidiary of Merck & Co., Inc. and Takeda Pharmaceutical Company Limited.

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), affinity maturation, 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 and capabilities of XOMA's technologies 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 generally unstable nature of current economic conditions; the results of discovery research 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 and licensing relationships; the ability of collaborators, licensees and other third parties 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
          Company and 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 April 19, 2010