XOMA Granted First European Patent Covering XOMA 052

BERKELEY, Calif., Nov. 4, 2009 (GLOBE NEWSWIRE) -- XOMA Ltd. (Nasdaq:XOMA), a
leader in the discovery and development of therapeutic antibodies, today
announced the grant of its first European Patent related to the XOMA 052
program. Granted by the European Patent Office, the patent covers XOMA's
interleukin-1 beta (IL-1 beta) antibody 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.

IL-1 beta is 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.
Earlier this year, XOMA completed successful Phase 1 trials of XOMA 052 in Type
2 diabetes patients, and has initiated its Phase 2 clinical development program
in Type 2 diabetes and cardiovascular disease.

"This new patent is XOMA's first European patent providing exclusivity for XOMA
052 and complements our two U.S. Patents, which issued earlier this year," said
Steven Engle, XOMA Chairman and Chief Executive Officer.

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 development
for Type 2 diabetes and cardiovascular disease, with potential
for the treatment of a wide range of inflammatory diseases
* 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 Institutes of Allergy and
Infectious Diseases of the National Institutes of Health
* 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), affinity
maturation 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
http://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 declining and 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.

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CONTACT: XOMA Ltd.
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