ReProduct Development Agrmnt

Cambridge Antibody Tech Group PLC
14 September 2000



00/CAT/12       


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For Further Information Contact:

Cambridge Antibody Technology        
Tel: [phone]
Dr David Glover, Medical Director        
John Aston, Finance Director
Rowena Gardner, Communications Manager


HCC De Facto (Europe)
Tel: [phone]
Nikul Odedra (trade)
Sue Charles (city/financial)


BMC Communications/The Trout Group (USA)
Tel: [phone]
Brad Miles, ext 17 (media)
Jonathan Fassberg, ext.16 (investors)


CAT ENTERS INTO PRODUCT DEVELOPMENT AGREEMENT WITH WYETH RESEARCH RELATING TO 
                       ALZHEIMER'S AMYLOID BETA TARGET                        

Melbourn, UK...  Cambridge Antibody Technology - (LSE:CAT) ('CAT') announced
today that it has granted Wyeth-Ayerst Research (the pharmaceutical research
unit of American Home Products Corporation - (NYSE:AHP)  an exclusive product
licence to develop antibody drug products specific for the amyloid ( peptide
that has been widely implicated in Alzheimer's disease. 

This development reflects the success of the broad collaboration between CAT
and Wyeth-Ayerst, signed in March 1999, to apply CAT's functional genomics and
antibody engineering expertise to the discovery of new therapeutics based on
targets identified by Wyeth-Ayerst.

Under terms of the product development agreement, CAT will receive an advance
licensing fee, and will potentially receive clinical milestones and royalties
associated with product sales. 



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Wyeth-Ayerst recently announced an alliance with Elan Corporation, plc to
develop  immuno-therapeutic agents that may be used for the treatment of mild
to moderate Alzheimer's disease and possibly prevent the onset of the disease.
The agreement between CAT and Wyeth-Ayerst allows Wyeth-Ayerst and Elan to use
CAT's technology to further explore both preventative and therapeutic
treatments for the disease.

'We are enthusiastic to be moving our collaboration with Wyeth-Ayerst forward
at this important and exciting time of discovery in the field of Alzheimer's
disease,' says David Chiswell, CEO of CAT. 'We believe amyloid ( to have
strong potential as a therapeutic antibody target, as Wyeth-Ayerst's and
Elan's target validation work in this area has demonstrated. We are also
confident our ongoing alliance with Wyeth will continue to help fuel our
antibody product pipeline.'



Notes to Editors:
                                                                              
                     Cambridge Antibody Technology (CAT)                      
* 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 180 people.  
* CAT is listed on the London Stock Exchange, having raised £41m in its IPO in
March 1997. An Open Offer and International Offering in March 2000 raised
£93m.
* 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.  Four 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, Wyeth-Ayerst, Human
Genome Sciences, AstraZeneca and  Pharmacia. 


         Wyeth-Ayerst (American Home Products Corporation: NYSE: AHP)         
Wyeth-Ayerst Laboratories, a division of American Home Products Corporation
(NYSE:AHP), is a major research-oriented pharmaceutical company with leading
products in the areas of women's health care, cardiovascular therapies,
central nervous system drugs, anti-inflammatory agents, infectious disease,
haemophilia, oncology, vaccines, and generic pharmaceuticals. American Home
Products Corporation (NYSE:AHP) is one of the worlds largest research-based
pharmaceutical and health care products companies.  It is a leader in the
discovery, development, manufacturing and marketing of prescription drugs and
over-the-counter medications.  It is also a leader in vaccines, biotechnology,
and animal health care.



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                    Elan Corporation plc (NYSE: ELN)                 
Elan is a leading worldwide speciality pharmaceutical and drug delivery
company headquartered in Ireland, with its principal research, development,
manufacturing and marketing facilities located in Ireland, the United States
and Israel.  Elan is focused on the discovery, development and marketing of
therapeutic products and services in neurology, pain management and oncology,
and on the development and commercialisation of products using its extensive
range of proprietary drug delivery technologies.  Elan's shares trade on the
New York, London and Dublin Stock Exchanges.  

                             Alzheimer's Disease                              
* Alzheimer's disease is a progressive, degenerative disease of the brain,
primarily afflicting older persons. Initial symptoms include simple confusion
and forgetfulness; ultimately leading to profound dementia.
* Alzheimer's disease affects one person in 10 over the age of 65, and almost
half of all persons over 85. These are the two most rapidly growing population
segments in Western Europe, the USA and Japan. 
* Approximately 15-million people worldwide suffer from Alzheimer's disease. 

                                   Amyloid                                    

* Amyloid ( plaques have been observed in the brains of people who died with
Alzheimer's disease and it is believed that it is the presence of these
plaques that leads to degeneration of cognitive function in Alzheimer's
patients).