Antibody Phage Display Patent Granted in US

CAMBRIDGE ANTIBODY TECHNOLOGY GROUP PLC
20 October 1999


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Cambridge Antibody Technology Group plc
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CAMBRIDGE ANTIBODY TECHNOLOGY GRANTED KEY ANTIBODY PHAGE DISPLAY PATENT IN US


Melbourn, UK    Cambridge Antibody Technology ('CAT') has been granted a
fundamental US patent covering the display of antibody fragments on phage (the
'McCafferty' patent).

The patent, no. US 5,969,108 entitled 'Methods for Producing Members of
Specific Binding Pairs,' is a key US patent that further strengthens CAT's
intellectual property position in the field of phage antibody display. It
provides protection in the US for the CAT Library - an extensive phage display
antibody library, currently incorporating around 100 billion distinct
antibodies - and for the therapeutic antibody products derived from it which
are being developed by CAT and its collaborative partners.

The McCafferty patent has claims relating to phage displaying a single chain
Fv fragment ('scFv') on its surface, host cells harbouring libraries of phage
displaying scFvs, scFvs isolated from such libraries and antibody products
constructed from these. The patent arises from work carried out by the Medical
Research Council and CAT. Similar patents have already been granted to CAT in
Europe, Australia and South Korea.


Dr David Chiswell, Chief Executive Officer of CAT, commented:

'The McCafferty patent adds to CAT's growing US patent estate covering the
phage display of antibodies. The US patent portfolio now includes patents
covering the display of antibodies on phage (McCafferty et al) and the
isolation of human antibodies to human proteins or other antigens by phage
display (Griffiths et al). Taken together with CAT's other patents granted
worldwide, the granting of this patent underscores the strengths of CAT's
patent position and confirms CAT's leadership in the development of human
antibodies.'


Notes to editors

1. Cambridge Antibody Technology (LSE: CAT) is a UK biotechnology company
using its proprietary technologies in fully human monoclonal antibodies for
drug discovery and drug development.  Based in Melbourn, 10 miles south of
Cambridge, England, CAT currently employs around 150 people.  In March 1997,
CAT completed its initial public offering and listing on the London Stock
Exchange, raising approximately £41 million.

CAT has a world-leading platform technology for rapidly isolating fully human
monoclonal antibodies using phage display systems. CAT has an extensive phage
display antibody library, currently incorporating around 100 billion distinct
antibodies. This library forms the basis for the company's strategy to develop
a portfolio of clinical development programmes and for discovering new drug
leads using functional genomics.  Three fully human therapeutic antibodies
developed by CAT are at various stages of clinical trials. 

CAT has a number of license and collaborative agreements in place with
pharmaceutical and biotechnology companies including: Eli Lilly, Pfizer, BASF
Pharma, Genentech, ICOS Corporation, Genetics Institute/BASF Pharma,
Wyeth-Ayerst, Human Genome Sciences and AstraZeneca.

2. CAT's patent portfolio gives CAT the freedom to operate its technology. CAT
currently has two main patent families covering antibody libraries (Winter II)
and phage display (McCafferty). 

CAT's Winter II and McCafferty patents have both been granted in Europe (9
April 1994 and 13 November 1996 respectively). 

The granted US McCafferty patent is entitled to a term expiring on 19 October
2016.

Griffiths et al (US 5,885,793): This patent was granted on 23 March 1999. It
refers to the isolation of human antibodies to human proteins by phage display
and to methods for producing human antibodies. 

3. The CAT Library is an extensive phage display antibody library, currently
incorporating around 100 billion distinct antibodies. The Library forms the
basis for the Company's strategy to develop a portfolio of clinical
development programmes and for discovering new drug leads using functional
genomics. The CAT Library is in use in the research laboratories of three
major biopharmaceutical companies in addition to CAT's own laboratories, where
research collaborations with a further five companies are taking place. 

4. ScFv: Single chain antibody fragments comprising the variable region of the
heavy chain fused via a linker peptide to the variable region of the light
chain

5. Antigen: A substance which induces the production of an antibody.

6. Medical Research Council (MRC) is the Medical Research Council of Great
Britain. The MRC owns some of the patent rights within CAT's patent portfolio
either wholly or jointly with CAT, which they have licenced to CAT under an
agreement dated 7 January 1997.