CAT and XOMA cross license

Cambridge Antibody Tech Group PLC
23 December 2002


02/CAT/29

FOR IMMEDIATE RELEASE

07.00 GMT 02.00 EST 23 December 2002

For further information contact:

Cambridge Antibody Technology                               Weber Shandwick Square Mile (Europe)
Tel: [phone]                                   Tel: [phone]
Peter Chambre, Chief Executive Officer                      Kevin Smith
John Aston, Chief Financial Officer                         Graham Herring
Rowena Gardner, Director of Corporate Communications

XOMA                                                        BMC Communications/The Trout Group (USA)
Tel: [phone]                                       Tel: [phone]
Laura Zobkiw                                                Brad Miles, ext 17 (media)
                                                            Brandon Lewis, ext.15 (investors)

Corporate Communications & Investor Relations

CAMBRIDGE ANTIBODY TECHNOLOGY AND XOMA CROSS-LICENSE ANTIBODY TECHNOLOGIES

Cambridge, UK and Berkeley, California, USA... Cambridge Antibody Technology
(LSE: CAT; NASDAQ: CATG) and XOMA Ltd. (NASDAQ: XOMA) announce today that they
have entered into a cross-licensing arrangement for antibody-related
technologies.

Under the agreement CAT, and its collaborators, receive rights to use the XOMA
antibody expression technology for developing products using CAT's phage-based
antibody technology, in return for licence payments to XOMA. XOMA will receive
the right to use CAT's phage antibody libraries for its target discovery and
research programmes, with an option to develop antibodies into therapeutics.
Should any therapeutic antibodies derived from CAT's libraries be identified and
developed by XOMA, licence payments will be made by XOMA to CAT.

Peter Chambre, CAT's Chief Executive Officer, commented, "Clarifying the
intellectual property issues in the antibody field remains an important priority
for both CAT and XOMA. As CAT progresses with its transition to a product-based
biopharmaceutical company, we are pleased to have reached this cross-licensing
arrangement with XOMA".

"We are very pleased to enter into this phage-based antibody related licensing
arrangement with CAT, a company with excellent capabilities in the important
field of antibody drug discovery," said Jack Castello, Chairman, President and
Chief Executive Officer of XOMA.  "Our licence to CAT, which is the fourth such
licence we've entered into with a significant antibody library company this
year, further validates the fundamental position our antibody expression
technology holds in the phage display arena."

-ENDS-

Notes to Editors:

Cambridge Antibody Technology (CAT)

CAT is a UK-based biotechnology company and a leader in the discovery and
development of human therapeutic antibodies: HumiraTM, the leading CAT-derived
antibody, has been submitted for regulatory review by Abbott (responsible for
development and marketing) following the completion of Phase III trials.  Six
other CAT-derived human therapeutic antibodies are at various stages of clinical
trials.

CAT has an advanced proprietary platform technology for rapidly isolating human
monoclonal antibodies using phage display systems. CAT has extensive phage
antibody libraries, currently incorporating more than 100 billion distinct
antibodies. These libraries form the basis for the Company's strategy to
discover and develop a portfolio of antibody-based drugs.

CAT has alliances with a large number of pharmaceutical and biotechnology
companies to discover, develop and commercialise human monoclonal antibody-based
products. CAT has also licensed its proprietary human phage antibody libraries
to several companies for target validation and drug discovery. CAT's
collaborators include: Abbott, Amgen, Amrad, Chugai, Elan, Genzyme, Human Genome
Sciences, Merck & Co, Pharmacia and Wyeth Research.

Based near Cambridge, England, CAT currently employs around 290 people.

CAT is listed on the London Stock Exchange and on NASDAQ since June 2001. CAT
raised £41m in its IPO in March 1997 and £93m in a secondary offering in March
2000.

Application of the Safe Harbor of the Private Securities Litigation Reform Act
of 1995:

This press release contains statements about Cambridge Antibody Technology Group
plc ("CAT") that are forward looking statements.  All statements other than
statements of historical facts included in this press release may be forward
looking statements within the meaning of Section 21E of the Securities Exchange
Act of 1934. These forward looking statements are based on numerous assumptions
regarding CAT's present and future business strategies and the environment in
which CAT will operate in the future.  Certain factors that could cause CAT's
actual results, performance or achievements to differ materially from those in
the forward looking statements include: market conditions, CAT's ability to
enter into and maintain collaborative arrangements, success of product
candidates in clinical trials, regulatory developments and competition.



XOMA

XOMA scientists were the first to demonstrate the secretion of antibody domains
directly from bacterial cells as fully functional, properly folded molecules.
XOMA has received nine U.S. patents to date relating to aspects of its bacterial
cell expression system, including six patents that broadly cover the secretion
of functional immunoglobulins from bacteria, including antibody fragments such
as Fab and single-chain antibodies.  Corresponding foreign patents have also
been granted.

Bacterial antibody expression is an enabling technology used to discover and
screen, as well as develop and manufacture, recombinant antibodies for
commercial purposes.  Bacterial antibody expression is also a key technology
used in multiple systems for high-throughput screening of antibody domains.
Further information on XOMA's bacterial cell expression technology can be found
at http://www.xoma.com/technologies_for_licensing/cell_expression.jsp.

XOMA develops and manufacturers innovative biopharmaceuticals for disease
targets that include cancer, immunological and inflammatory disorders, and
infectious diseases.  XOMA's programs include collaborations: with Genentech,
Inc. on the RaptivaTM antibody for psoriasis (Phase III), rheumatoid arthritis
(Phase II) and other indications; with Onyx Pharmaceuticals, Inc. to develop and
manufacture its ONYX-015 product for various cancers (Phase II and III); with
Baxter Healthcare Corporation to develop NEUPREX(R) (rBPI-21) for Crohn's
disease (Phase II) and other indications; and with Millennium Pharmaceuticals,
Inc. on two biotherapeutic agents, CAB-2 and MLN-01, for certain vascular
inflammation indications (preclinical).  Earlier-stage development programs
include compounds to treat cancer, retinopathies, autoimmune diseases and
infections.  For more information about XOMA's pipeline and activities, please
visit XOMA's web site.

Statements made in this news release to collaborative arrangements and
development capabilities, 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 changes
in the status of existing collaborative relationships, the availability of
future collaborative relationships, the ability of collaborators and other
partners to meet their obligations, the timing of results of pending or future
clinical trials, market demand for products, actions by the Food and Drug
Administration or the US Patent and Trademark Office, and uncertainties
regarding the status of biotechnology patents, are discussed in XOMA's most
recent annual report on Form 10-K and in other SEC filings.  Consider such risks
carefully in evaluating XOMA's prospects.

                      This information is provided by RNS
            The company news service from the London Stock Exchange