Clinical Trial Update

Cambridge Antibody Tech Group PLC
09 February 2004

04/CAT/06

FOR IMMEDIATE RELEASE

07.00 GMT, 02:00 EST Monday 9 February 2004

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                 Rachel Lankester
Rowena Gardner, Director of Corporate               
Communications
                                                    BMC Communications/The Trout Group (USA)
                                                    Tel: [phone]
                                                    Brad Miles, ext 17 (media)
                                                    Brandon Lewis, ext 15 (investors)

Genzyme Corp.
Media: Dan Quinn, Tel: [phone]
Investors: Sally Curley, Tel: [phone]



CAMBRIDGE ANTIBODY TECHNOLOGY AND GENZYME ANNOUNCE PRELIMINARY RESULTS FROM
PHASE I/II TRIAL OF CAT-192 FOR SCLERODERMA

Cambridge, UK and Cambridge, Mass... Cambridge Antibody Technology (LSE:
CAT; NASDAQ: CATG) and Genzyme Corp. (NASDAQ: GENZ) today announce preliminary
results from a Phase I/II clinical trial of CAT-192, a human anti-TGFb1
monoclonal antibody. The primary objective of the trial was to assess the
safety, tolerability and pharmacokinetics of CAT-192 in patients suffering from
diffuse systemic sclerosis.  The secondary objective was to evaluate the
potential clinical outcomes for any future trial in systemic sclerosis.

The double-blind, placebo-controlled trial enrolled 45 patients at 12 medical
centres in the United States and Europe. Patients were randomised to receive one
of three dose levels of CAT-192 (0.5mg/kg, 5 mg/kg or 10 mg/kg) or matching
placebo, given as an intravenous infusion every six weeks for four doses.

Preliminary results show that the primary objective was met; CAT-192 was
generally safe and well-tolerated at each dose level. Elimination half-life was
consistently around three weeks. There were no treatment-related serious adverse
events observed.  Four patient deaths occurred during the trial (one at 0.5 mg/
kg and three at 5 mg/kg) and were determined by independent medical reviewers to
be attributable to patients' underlying disease, and unrelated to
treatment.

For the secondary objective of the trial a number of clinical endpoints and
biological markers, potentially indicative of disease progression, were
evaluated. Preliminary review of these markers indicated that disease duration
and gender played important roles in the results, and that the placebo group's 
skin score did not deteriorate during the trial as anticipated. Given
these factors and the small sample size, no definitive conclusions regarding the
efficacy of CAT-192 can be drawn at this time. Additional analyses and
alternative trial designs are being evaluated.

"The clinical development teams from both companies are encouraged by
the safety and pharmacokinetic results seen in this trial," said Dr
David Glover, chief medical officer at Cambridge Antibody Technology. "We have 
gained useful insights that will help determine the next steps in our
clinical development programme. We will continue to evaluate the data, and to
work with scleroderma experts to determine how to progress in the future."

"We are continuing our efforts to target TGF-beta through a variety of human
monoclonal antibodies, an approach that we believe has great potential in the
development of effective therapies for scleroderma and other fibrotic diseases,
added Dr Richard Moscicki, Genzyme's chief medical officer.

The companies expect that the results of the trial will be submitted for
presentation at a major scientific conference later this year.

-ENDS-

Notes to Editors

About Scleroderma:

•       Diffuse systemic sclerosis, a form of scleroderma, is a chronic,
life-threatening disorder caused by the production of excess collagen which
leads to scarring of the skin and internal organs.  Eighty percent of those
affected by this disease are women between the ages of 25-55.  About 40 per cent
of all patients with this disorder die within ten years of diagnosis.  There is
currently no effective therapy for the disease, which affects an estimated
300,000 people worldwide.

•      Genzyme and CAT have been working in partnership to develop and
commercialise human TGFb monoclonal antibodies for the treatment of diffuse
systemic sclerosis since September 2000.

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 and ribosome 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.

•       Three CAT human therapeutic antibody products are now in clinical
development, with two further product candidates in pre-clinical development.

•       HUMIRATM, the leading CAT-derived antibody, isolated and optimised in
collaboration with Abbott has

•       been approved by the US Food and Drug Administration for marketing in
the US and by the European Commission for marketing in the EU as a treatment for
rheumatoid arthritis.

•       Five further licensed CAT-derived human therapeutic antibodies in
clinical development, with three further licensed product candidates in
pre-clinical development.

•       CAT has alliances with a number of pharmaceutical and biotechnology
companies to discover, develop and commercialise human monoclonal antibody-based
products. In particular, CAT has a broad collaboration with Genzyme for the
development and commercialisation of antibodies directed against TGFb, a family
of proteins associated with fibrosis and scarring. This collaboration has so far
given rise to one antibody product candidate at clinical development stage, and
one at pre-clinical development stage.

•       CAT has also licensed its proprietary technologies to several companies.
CAT's licensees include: Abbott, Amgen, Chugai, Human Genome Sciences,
Merck & Co, Pfizer 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 the company's present and future business
strategies and the environment in which the company will operate in the future.
Certain factors that could cause the company'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. We caution investors
not to place undue reliance on the forward looking statements contained in this
press release. These statements speak only as of the date of this press release,
and we undertake no obligation to update or revise the statements.

Genzyme Corporation:

•       Genzyme Corporation is a global biotechnology company dedicated to
making a major positive impact on the lives of people with serious diseases.
The company's broad product portfolio is focused on rare genetic
disorders, renal disease, osteoarthritis and immune-mediated diseases, and
includes an industry-leading array of diagnostic products and services. 
Genzyme's commitment to innovation continues today with research into novel
approaches to cancer, heart disease, and other areas of unmet medical need.
More than 5,300 Genzyme employees in offices around the globe serve patients in
over 80 countries.

This press release contains forward-looking statements, including statements
about: preliminary results from a clinical trial of CAT-192; potential
additional studies; product development plans and the potential utility of
targeting TGFss in developing therapies for fibrotic diseases; the anticipated
timing of presentation of the results from the trial; and estimates regarding
the diffuse systemic sclerosis patient population.  These statements are subject
to risks and uncertainties that could cause actual results to differ materially
from those projected in these forward-looking statements.  These risks and
uncertainties include, among others: the final analysis of the clinical trial
data and the actual timing thereof; the results and timing of additional
preclinical and clinical studies; the accuracy of the companies' information 
concerning the scleroderma patient population; and the risks and uncertainties 
described in reports filed by Genzyme Corporation with the U.S. Securities and 
Exchange Commission, including without limitation the factors discussed under 
the caption "Factors Affecting Future Operating Results" in Genzyme's Quarterly 
Report on Form 10-Q for the fiscal quarter ended September 30, 2003. We caution 
investors not to place undue reliance on the forward-looking statements 
contained in this press release.  These statements speak only as of the date of 
this press release, and we undertake no obligation to update or revise the 
statements.

•       Genzyme(R) is a registered trademark of Genzyme Corporation. All rights
reserved.

•       Genzyme's press releases and other company information are
available at www.genzyme.com and by calling Genzyme's investor
information line at 1-800-905-4369 within the United States or 1-703-797-1866
outside the United States.



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