Re Collaboration Agreement

Cambridge Antibody Tech Group PLC
4 December 2000


For further information contact:

Cambridge Antibody Technology        
Tel: [phone]
Kevin Johnson, Research Director
John Aston, Finance Director       
Rowena Gardner, Head of Corporate Communications       

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

Zyomyx, Inc
Tel: [phone]
Lawrence K Cohen, PhD, Chief Operating Officer 
                                                                              
BMC Communications/The Trout Group (USA)
Tel: [phone]
Brad Miles, ext.17 (media)
Brandon Lewis, ext.15 (investors)



ZYOMYX AND CAMBRIDGE ANTIBODY TECHNOLOGY COLLABORATE TO DEVELOP 
ANTIBODY ARRAY PROTEIN BIOCHIP

Melbourn, UK and Hayward, CA  Cambridge Antibody Technology (LSE: CAT) and
Zyomyx, Inc. today announce that they have entered into a collaboration for
the development of high-density protein biochips based on antibody arrays. 
Under the terms of the agreement, Zyomyx and CAT will jointly develop parallel
antibody arrays for the detection of proteins from complex biological
mixtures.  CAT will supply human antibody fragments from its proprietary phage
display libraries and Zyomyx will provide technology and know-how in protein
biochip systems. 

As DNA Chips have revolutionised the sequencing of genes and measurement of
their transcriptional activity, Zyomyx applies its novel biochip technologies
and advanced materials science techniques to the study of proteins in a fully
functional state.  Zyomyx believes this technology platform to be unique and
superior to existing protein profiling tools and will be the first to permit
the measurement of protein abundance, structure and activity in parallel, as
well as allowing the study of protein-protein and protein-small molecule
interactions. 

CAT is the world leading company in the development of fully human antibodies
by phage display and has considerable expertise and know-how in high
throughput systems for the isolation and functional screening of antibodies
from its libraries.  The agreement between CAT and Zyomyx is an opportunity to
combine the technology strengths of both companies in assessing the
functionality and versatility of protein biochips.  This is CAT's second
collaboration in what it expects to be a series of world-leading protein chip
alliances.

CAT's Research Director, Dr. Kevin Johnson, commented 'We believe the protein
biochip will soon be an important analytical tool for the drug discovery
community.  The combination of CAT's world-leading antibody technology and
expertise with Zyomyx' novel protein biochip technology will provide an
important step in advancing technology in this new and exciting area of
proteomics.'

'CAT is a leader in the discovery and development of human monoclonal
antibodies,' stated Peter Wagner, Ph.D., Chief Technical Officer of Zyomyx. 
'With Zyomyx' unique expertise in the protein biochip arena, we believe this
joint effort will accelerate the development of advanced protein biochip
technologies.  We are pleased to have CAT as our partner in this endeavour. 
CAT's high-throughput antibody selection expertise is a perfect match for our
high-density biochip capacities.'


Notes to Editors:

Cambridge Antibody Technology (LSE: 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 nearly
200 people.  
CAT is listed on the London Stock Exchange, having raised £41m in its IPO in
March 1997.             A secondary 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 programs 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 works in partnership with other companies at all stages of the drug
discovery and development process. CAT's collaborations, past and present,
include: AstraZeneca, BASF Pharma, Eli Lilly, Genentech, Genetics Institute,
Genzyme, Human Genome Sciences, Immunex, Oxford GlycoSciences, Pharmacia
Corporation, Pfizer, Wyeth-Ayerst 

Zyomyx, Inc. 
Located in Hayward, California, Zyomyx, Inc., seeks to bridge the gap between
genomic information and protein function through the development of protein
biochips.  The Company has successfully integrated protein biochemistry with
advanced materials science and microfabrication to create the first
miniaturised chip containing high-density arrays of functional proteins for
use in drug discovery and diagnosis.  Zyomyx' lead product, the Proteomics
Biochip, is designed to accelerate target discovery and validation for the
pharmaceutical drug development process. Zyomyx' has an ongoing development
partnership with Fujirebio, Inc.