XOMA Announces $6 Million Antibody Discovery Collaboration With Arana Therapeutics

XOMA Announces $6 Million Antibody Discovery Collaboration With Arana Therapeutics

BERKELEY, Calif., Sept. 9, 2009 (GLOBE NEWSWIRE) -- XOMA Ltd. (Nasdaq:XOMA) and
Arana Therapeutics Limited, a wholly-owned subsidiary of Cephalon, Inc.
(Nasdaq:CEPH) have entered into a collaboration 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. Arana has agreed to pay XOMA a fee of $6 million and XOMA will be
entitled to milestone payments and royalties on product sales. Under the terms
of the collaboration, XOMA will be fully reimbursed for all services it may
provide to Arana under the agreement.

"We selected XOMA because of their ability to provide a complete suite of
validated technologies that will further enable us to accelerate our antibody
development programs toward the clinic," said Steffen Nock, Acting Chief
Executive Officer of Arana. "We believe the advantages of these technologies,
including XOMA's next-generation antibody libraries, will increase our capacity
to cost-effectively develop novel therapeutics."

"We are pleased to partner with Arana, a company with a strong presence and
capabilities in the antibody field," said Steven B. Engle, XOMA's Chairman and
Chief Executive Officer. "This monetization of our proprietary technologies and
products demonstrates the value of our extensive antibody expertise and
increases the return on our research and development efforts."

XOMA has developed integrated capabilities in antibody discovery, engineering
and manufacturing, including maintaining the largest collection of commercially
available antibody phage display libraries. The company also has expertise in
the construction of large, novel and diverse libraries for screening and
optimization that enable the selection of antibodies with very specific binding,
affinity and potency characteristics to an antigen of choice.

The new, proprietary antibody library covered by the agreement with Arana,
recently validated by XOMA, is one of a series of proprietary antibody libraries
being developed by XOMA scientists to overcome existing limitations in library
design by combining "best-in-class" techniques with XOMA's own proprietary and
patent-protected technologies. Access to multiple libraries may offer a number
of benefits to XOMA and its partners because it enables the use of libraries
best suited to the needs of a particular discovery project. This increases the
probability of technical and business success in finding rare and unique
functional antibodies directed to targets of interest.

About XOMA

XOMA discovers, develops and manufactures therapeutic antibodies designed to
treat inflammatory, autoimmune, infectious and oncological diseases. The
Company's proprietary product pipeline includes XOMA 052, an anti-IL-1 beta
antibody, and XOMA 3AB, a biodefense anti-botulism antibody candidate.

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 leading, unmatched capabilities in antibody phage display and a
unique collection of antibody display libraries, as well as XOMA's proprietary
Targeted Affinity Enhancement technology for antibody humanization and bacterial
cell expression and manufacturing technologies. Bacterial cell expression 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.

The company's integrated processes use proprietary informatics systems that:

* Increase efficiencies for data management and analysis
* Support rational data-driven decisions thus reducing costly errors
* Increase capacity for multiple antibody programs with limited
* Accelerate product development and
* Support intellectual property filings.
In addition to developing its own products, XOMA develops products with premier
pharmaceutical companies including Novartis AG, Schering-Plough Research
Institute and Takeda Pharmaceutical Company Limited. XOMA has a fully integrated
product development infrastructure and a team of approximately 190 employees at
its Berkeley, California location. For more information, please visit

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 XOMA's ability to renegotiate the requirements of its loan
agreements; the declining and 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); uncertainties regarding the status
of biotechnology patents; uncertainties as to the cost of protecting
intellectual property; changes in the status of the existing collaborative and
licensing relationships; the ability of collaborators, licensees and other third
parties to meet their obligations; market demand for products; scale up and
marketing capabilities; competition; international operations; share price
volatility; XOMA's financing needs and opportunities; and risks associated with
XOMA's status as a Bermuda company, are described in more detail in XOMA's most
recent annual report on Form 10-K and in other SEC filings. Consider such risks
carefully in considering XOMA's prospects.

The XOMA Ltd. logo is available at

          Company and Investor Contact:
          Carol DeGuzman
          [email protected]

          Porter Novelli Life Sciences
          Media Contact:
          Carolyn Hawley
          [email protected]