Re Agreement

Cambridge Antibody Tech Group PLC
20 May 2002


02/CAT/21

FOR IMMEDIATE RELEASE

07.00 BST, 02.00 EST Monday 20 May 2002
For Further Information Contact:

Cambridge Antibody Technology              Weber Shandwick Square Mile (Europe)

Tel: [phone]                  Tel: [phone]

Peter Chambre, CEO                         Kevin Smith

John Aston, Finance Director               Graham Herring

Rowena Gardner, Head of Corporate
Communications
Human Genome Sciences:                     BMC Communications/The Trout Group (USA)

Ellen S. Baron, PhD, SVP Business          Tel: [phone]
Development
                                           Brad Miles, ext 17 (media)
Tel: [phone]
                                           Brandon Lewis, ext.15 (investors)
Jerry Parrott, VP Corporate Communications

Tel: [phone]

Kate de Santis, Director, Investor
Relations

Te: 001 301 251 6003



  CAMBRIDGE ANTIBODY TECHNOLOGY AND HUMAN GENOME SCIENCES COMMIT TO EXCLUSIVE
                  DEVELOPMENT OF ANTIBODY TO TRAIL RECEPTOR-2

TRAIL Receptor-2 human monoclonal antibody to be developed for cancer treatment

Melbourn, UK and Rockville, Maryland, USA... Cambridge Antibody Technology (LSE:
CAT; NASDAQ: CATG) and Human Genome Sciences Inc. (NASDAQ: HGSI) today announce
that HGSI has exercised an option to enter into an exclusive development
partnership on a human monoclonal antibody to TRAIL Receptor-2 (TRAIL-R2 mAb).
TRAIL-R2 mAb is an agonistic antibody that specifically recognises the TRAIL
Receptor-2 protein, found on the surface of a number of cancer cell types.

In pre-clinical studies, TRAIL-R2 mAb has demonstrated the ability to reduce or
prevent the growth of certain tumours in animal models.

HGSI discovered TRAIL Receptor-2. TRAIL Receptor-2 is a member of the tumour
necrosis factor (TNF) family of receptors, and is called a "death receptor"
because of its ability to cause tumour cell death when triggered by the natural
ligand TRAIL (tumour necrosis factor-related apoptosis-inducing ligand). TRAIL
Receptor-2 has been shown to be expressed on a number of solid tumours,
including lung, prostate and breast tumours, and tumours of hematopoietic
origin. It has been demonstrated that cell lines derived from such tumours are
sensitive to killing by apoptosis induced by binding to TRAIL and TRAIL-R2 mAb.

Unlike the natural TRAIL ligand, TRAIL-R2 mAb does not bind to the surface
proteins DcR1 and DcR2 or the soluble receptor osteoprotegerin. TRAIL binds to
these proteins, but such binding does not trigger cell death.

HGSI and CAT announced an antibody product development alliance in early 2000.
The agreement provides HGSI with rights to use CAT's antibody technology to
develop and sell human antibodies for therapeutic and diagnostic purposes. In
return, CAT is entitled to receive licence fees, clinical development milestones
and royalties on product sales from HGSI.

TRAIL-R2 mAb is the third HSGI antibody drug candidate to emerge from the
collaboration between HGSI and CAT. The others are TRAIL-R1 mAb, a human
monoclonal antibody to TRAIL Receptor-1 for use in treating certain cancers, and
LymphoStat-BTM, a human monoclonal antibody to BLySTM (B-lymphocyte stimulator)
for use in treating lupus and rheumatoid arthritis. HGSI holds the commercial
rights to all three drugs. These drugs will be produced in the HGSI
manufacturing facility located in Rockville, Maryland, USA.

Peter Chambre, CAT's CEO, said, "We are delighted that our collaboration with
Human Genome Sciences continues to progress rapidly. We are proud to follow the
achievements on the TRAIL-R1 human antibody with the successful isolation of the
TRAIL-R2 human antibody. Significantly, TRAIL-R2 mAb, like TRAIL-R1 mAb, is
directed to a cell-surface receptor protein. We look forward to further success
in our collaboration with HGSI."

William A. Haseltine PhD, Chairman and Chief Executive Officer of Human Genome
Sciences, said, "Our collaboration with Cambridge Antibody Technology is clearly
productive. In November 2001, we announced clearance by the US Food and Drug
Administration to initiate human testing of LymphoStat-B for use in treating
lupus and rheumatoid arthritis. At the end of April 2002, we announced clearance
to initiate human testing of TRAIL-R1 mAb for use in treating solid tumours and
tumours of hematopoietic origin. TRAIL-R1 mAb is specific to TRAIL Receptor-1,
while TRAIL-R2 mAb is specific to TRAIL Receptor-2. The activity of both
molecules is novel. Both are designed to mimic the activity of the natural TRAIL
ligand, which stimulates these receptors to cause cancer cell death through
apoptosis. Both also are designed to have the advantage of a longer half-life
and the potential for greater efficacy than TRAIL itself. We look forward to
completing the pre-clinical development of TRAIL-R2 mAb, and to entering this
promising anti-tumour drug candidate into clinical trials."

                                     -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.



Human Genome Sciences Inc. (HGSI)

  • Human Genome Sciences is a company with the mission to treat and cure
    disease by bringing new gene-based drugs to patients.
  • HGS, Human Genome Sciences, BLyS, and LymphoStat-B are trademarks of Human
    Genome Sciences, Inc.



References

  • Salcedo, Alderson, Basu, et al. TRM-1, a human TRAIL-R1 agonistic
    monoclonal antibody, displays in vitro and in vivo anti-tumour activity,
    American Association for Cancer Research 93rd Annual Meeting, April 2002,
    Abstract 4240.
  • Ashkenazi A, Apo-2L/TRAIL in Cytokine Reference, Academic Press; 2000.
  • Salcedo, Alderson, Basu, et al. TRM-1, a human TRAIL-R1 agonistic
    monoclonal antibody, displays in vitro and in vivo anti-tumor activity,
    American Association for Cancer Research 93rd Annual Meeting. April 2002,
    Abstract 4240
  • Ashkanazi A, Dixit VM, 1998, Death Receptors signaling and modulation.
    Science 281, 1305-1308.
  • Cambridge Antibody Technology and Human Genome Sciences Inc. Create Major
    Alliance Dedicated to Developing Human Antibody Therapeutics Against
    Genomics Targets, 1 March, 2002.
  • Cambridge Antibody Technology and Human Genome Sciences Inc. Announce
    Second Drug Partnership, 8 January, 2002.
  • Cambridge Antibody Technology and Human Genome Sciences Inc. Commit to
    Exclusive Development of Anti-BLys Antibodies, 30 October 2000 (00/CAT/05).
  • Human Genome Sciences Inc. Initiates Trial of a New Drug for Systemic
    Lupus Erythematosus and Other Autoimmune Diseases, 1 November , 2001.
  • Human Genome Sciences Inc. Initiates Clinical Development of a Novel
    Anticancer Drug, 30 April, 2002.



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.


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