CAT and Xerion Collaboration

Cambridge Antibody Tech Group PLC
13 August 2002



02/CAT/22

FOR IMMEDIATE RELEASE

08.00 BST, 03.00 EST Tuesday 13 August 2002

For Further Information Contact:

                              
Cambridge Antibody Technology Weber ShandwickSquare Mile (Europe)
                              
Tel: [phone]     Tel: [phone]

Peter Chambre, Chief          Kevin Smith
Executive Officer
                              Graham Herring
John Aston, Chief Financial
Officer

Rowena Gardner, Director of
Corporate Communications

BMC Communications/The Trout Group (USA)     Xerion Pharmaceuticals

Tel: [phone]                        Tel: [phone]

Brad Miles, ext 17 (media)                   Alexander Gasket

Brandon Lewis, ext.15(investors)


    Cambridge Antibody Technology and Xerion Pharmaceuticals Enter Research
                                 Collaboration


Melbourn, UK and Martinsried, Germany.... Cambridge Antibody Technology (LSE:
CAT; NASDAQ: CATG) and Xerion Pharmaceuticals AG today announce the expansion of
their existing business relationship into a research collaboration for target
characterisation and drug discovery.

CAT and Xerion will explore and evaluate the therapeutic potential of a cell
surface protein known to play a role in allergic reactions in man. CAT will
provide specific human antibodies, originally derived from its proprietary phage
display libraries, as well as know-how in the target's biology and functional
assays. The antibodies will be applied by Xerion using its XCALIbur(R) target
validation technology to investigate new

mechanisms of intervention in allergic disease. CAT and Xerion will jointly own
the target intellectual property generated.

Xerion has already successfully applied CAT technology for target validation
following an antibody library licence agreement entered into by the two
companies in June 2001.

Peter Chambre, CAT's CEO, commented: "We are delighted that Xerion has achieved
success in under a year of using CAT's antibody libraries in combination with
its XCALIbur technology. We believe that the combination of the approaches and
capabilities of CAT and Xerion provides a significant opportunity to create
value in the validation of new targets for drugs against allergic reaction."

Dr. Markus Ewert, President and CEO of Xerion, commented: "We have been pleased
about the quality of our relationship with CAT, and are very happy to be working
more closely with CAT as a result of this new agreement. We are excited by the
possibility that, together, our powerful technologies could assist in exploring
new mechanisms of disease intervention in allergy."

The collaboration is designed on a shared costs/shared rights basis and no
further financial details are being disclosed.

                                     -ENDS-


Notes to Editors:

Cambridge Antibody Technology (CAT)

CAT is a UK-based biotechnology company using its proprietary technologies and
capabilities in human monoclonal antibodies for drug discovery and drug
development. Based near Cambridge, England, CAT currently employs around 270
people.

CAT is a leader in the discovery and development of human therapeutic antibodies
and 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 develop a portfolio of antibody-based drugs.

Six CAT-derived human therapeutic antibodies are at various stages of clinical
trials, with a seventh CAT-derived antibody, D2E7, having been submitted for
regulatory review by Abbott (responsible for development and marketing)
following the completion of Phase III trials.

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 , Amrad, Elan, Genzyme, Human Genome Sciences,
Immunex, Merck & Co, Pharmacia and Wyeth-Ayerst.


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.



Xerion Pharmaceuticals AG

Xerion Pharmaceuticals AG is a biopharmaceutical company that bridges the
process from target discovery to drug development in an unprecedented manner:
integrated functional identification and evaluation of disease relevant drug
targets followed by therapeutic antibody development against these high quality
targets. These competencies enable Xerion and its partners to advance into the
drug development process at accelerated speed. Its functional proteomics
platform (Xcelerate(R) and XCALIbur(R)) directly addresses protein function,
enabling rapid and precise target identification and validation. Xerion
Pharmaceuticals has license and collaborative agreements with Altana Pharma AG,
Cambridge Antibody Technology Ltd., Procorde GmbH, Xantos Biomedicine AG,
nanotype GmbH, TILL Photonics GmbH, and several research institutes.



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.


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            The company news service from the London Stock Exchange
     
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