HUMIRA Update

Cambridge Antibody Tech Group PLC
23 May 2003


03/CAT/13

FOR IMMEDIATE RELEASE

15.00 BST, 10.00 EST, Friday 23 May 2003


For further information contact:
Cambridge Antibody Technology                      Weber Shandwick Square Mile (Europe)
Tel: [phone]                          Tel: [phone]
Peter Chambre, Chief Executive Officer             Graham Herring
John Aston, Chief Financial Officer                Kevin Smith
Rowena Gardner, Director of Corporate
Communications
                                                   BMC Communications/The Trout Group (USA)
                                                   Tel: [phone]
                                                   Brad Miles, ext 17 (media)
                                                   Brandon Lewis, ext.15 (investors)


CAMBRIDGE ANTIBODY TECHNOLOGY REPORTS GRANTING OF POSITIVE OPINION FOR HUMIRATM
BY EUROPEAN MEDICINES EVALUATION AGENCY

Cambridge, UK...  Cambridge Antibody Technology (LSE: CAT; NASDAQ: CATG)
today acknowledges the announcement by Abbott Laboratories that the European
Medicines Evaluation Agency (EMEA) has granted a positive opinion on
HUMIRA (TM) (adalimumab, previously known as D2E7) for the treatment of
rheumatoid arthritis (RA). HUMIRA was isolated and optimised by CAT and Abbott
Laboratories as part of a broad scientific collaboration. Abbott Laboratories
filed for European Union (EU) approval in April 2002.

In an announcement dated 22 May 2003, Abbott Laboratories stated that the
European Commission (EC) is expected to issue an authorization for marketing
HUMIRA in EU countries in approximately 90 days. HUMIRA will be sent to
pharmacies in Germany and the UK within two weeks of receipt of the marketing
authorization.

CAT will receive royalties on the sales of HUMIRA. In addition, approval in a
country other than the US will trigger a milestone payment to CAT from Abbott
Laboratories.

Abbott Laboratories reported that the positive opinion on HUMIRA, granted
through the EMEA's Committee for Proprietary Medicinal Products (CPMP), was
based on data obtained in four controlled clinical trials. In total, 23 trials
have been conducted with HUMIRA, involving more than 2,400 RA patients
worldwide.

Abbott Laboratories also stated that HUMIRA will become the first human
monoclonal antibody approved in Europe for RA, and the first tumour necrosis
factor alpha (TNF-a) antagonist approved with an indication for use with
methotrexate or as monotherapy. HUMIRA is indicated for the treatment of
moderate to severe active RA when the response to disease modifying
anti-rheumatic drugs (DMARDs), including methotrexate, has been inadequate. To
ensure maximum efficacy, HUMIRA is given in combination with methotrexate.
HUMIRA can be given as monotherapy in case of intolerance to methotrexate or
when continued treatment with methotrexate is inappropriate.

As set out in CAT's interim results for the six months ended 31 March
2003, CAT's entitlement to royalties in relation to sales of Humira is
governed by an agreement dated 1 April 1995 between Cambridge Antibody
Technology Limited and Knoll Aktiengesellschaft (now a subsidiary of Abbott
Laboratories). The agreement allows for offset, in certain circumstances, of
royalties due to third parties against royalties due to CAT, subject to a
minimum royalty level.  Abbott indicated to CAT in March 2003 its wish to
initiate discussions regarding the applicability of these royalty offset
provisions for Humira. CAT believes strongly that the offset provisions do not
apply and will seek an outcome consistent with that position.


- 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 
     290 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.

•    Humira(TM) is the leading CAT-derived antibody. Six other CAT-derived human
     therapeutic antibodies are at various stages of clinical 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, Amgen, Amrad, 
     Chugai, Elan, Genzyme, Human Genome Sciences, Merck & Co, Pharmacia and 
     Wyeth Research.

•    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.


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