Xenova Group PLC

Re Agreement

Xenova Group PLC
23 April 2002

                             N e w s  R e l e a s e

                                                           FOR IMMEDIATE RELEASE

                                   Xenova Group plc
 Potential US$63m (£43.2m) Development and Licence Agreement with Genentech Inc
                 for Novel Drugs in Immune Inflammatory Disease

Slough, UK, 23 April, 2002 - Xenova Group plc (Nasdaq NM: XNVA; London Stock
Exchange: XEN) today announces that it has signed an exclusive development and
licence agreement with South San Francisco-based Genentech Inc (NYSE: DNA) worth
up to US$63m plus royalties. The agreement provides Genentech with worldwide
rights to develop and market products primarily targeting disorders of the
immune system based on Xenova's OX40 receptor protein and anti-OX40 Ligand
antibody programmes.

Genentech will pay Xenova licence fees of up to US$5m (£3.4m) over the first
year of the collaboration.  In addition, Genentech will pay Xenova up to US$58m
(£39.7m) in milestones assuming successful development and commercialisation of
a product. Significant tiered royalties, depending on the level of sales, are
also receivable by Xenova.

Genentech has also acquired an option, but not an obligation, to develop a
second product.  Should a second product be developed and commercialised,
further milestone payments and royalties would apply.

Xenova will transfer to Genentech responsibility for the further development of
the relevant programmes, including preclinical and clinical trials, all
regulatory filings and the manufacture and sale of any products arising from the
agreement worldwide. Genentech will fund all future development activities
within the scope of the agreement.

Xenova retains for its proprietary development and commercialisation in oncology
and other applications all rights to OX40 Ligand and stimulatory anti-OX40
antibodies. Xenova's OX40 platform technology is part of the portfolio of
pre-clinical research programmes acquired through its merger with Cantab
Pharmaceuticals plc in 2001.

OX40 is a platform technology capable of producing several therapeutic
solutions.  OX40 and OX40 Ligand are a pair of interacting cell-surface proteins
which are important for the induction and regulation of immunity. The
therapeutic potential of these cell-surface proteins lies in their ability to
modulate the immune system. Modulation of the immune system has the potential to
be of benefit in a wide range of diseases including inflammatory and autoimmune
disease, infectious diseases and cancer.  Xenova is the holder of exclusive
licences to several patents relating to the OX40 platform.

David Oxlade, Chief Executive of Xenova, commented:

'We are delighted with this new agreement with Genentech, our third major
partnership in the last 8 months.  Genentech has a remarkable track record in
successfully bringing innovative therapeutic solutions to market in this field.
The OX40 mechanism has been shown to be a key component of the body's immune
system and is an important new therapeutic target. This agreement highlights the
enhanced commercial potential in Xenova's research portfolio since the merger
with Cantab and realises both immediate and long term value for the company.  It
also clearly illustrates our strategy of seeking partnerships with major players
who are capable of exploiting our science in applications which lie outside our
main focus on cancer and immunotherapy.'


UK:                                                 US:
Xenova Group plc                                    Trout Group/BMC Communications
Tel: +44 (0)1753 706600                             Tel: 001 212 477 9007
David A Oxlade, Chief Executive Officer             Press: Brad Miles (Ext 17) Lauren Tortorete (Ext 20)
Daniel Abrams, Group Finance Director               Investors: Jonathan Fassberg (Ext 16) Lee Stern (Ext 22)
Hilary Reid Evans, Corporate Communications

Financial Dynamics
Tel: +44 (0)207 831 3113
David Yates/Fiona Noblet

Notes to Editors

OX40: OX40 Ligand - The OX40/OX40L receptor-ligand mechanism provides a platform
technology which is capable of producing several drug candidates.  OX40 and
OX40L are a pair of interacting cell-surface proteins which act as
co-stimulatory molecules in the initiation of the immune cascade.  The
therapeutic potential of these products lies in their ability to regulate the
T-cell/antigen presenting cell interaction, thereby modulating immunological
signals which are central to a wide range of disease processes, including
autoimmune disease, cancer and infectious diseases.

Celltech Group plc and OX40 - Xenova has an existing OX40-related partnership
with the UK-based Celltech Group plc, under the terms of which Celltech is
developing an anti-OX40 antibody based product for the treatment of autoimmune
disease. This application of the technology falls within Xenova's retained
rights and is independent of Genentech's licence.

Xenova Group plc's product pipeline focuses principally on the therapeutic areas
of cancer and immune system disorders.  Xenova currently has a broad pipeline of
eight programmes in clinical development.  Xenova's lead programme is a
P-glycoprotein antagonist for the treatment of multi-drug resistance in cancer,
known as tariquidar or XR9576.  Tariquidar has completed a successful series of
three Phase IIa clinical trials and is expected to enter Phase III clinical
development in mid 2002.  Tariquidar was partnered for the North American market
with QLT Inc in August 2001. The Group has a well-established track record in
the identification, development and partnering of innovative products and
technologies and has partnerships with other major pharmaceutical companies
including Lilly, Pfizer, Celltech and Millennium Pharmaceuticals.

For further information about Xenova and its products please visit the Xenova
website at www.xenova.co.uk

For Xenova: Disclaimer to take advantage of the 'Safe Harbor' provisions of the
US Private Securities Litigation Reform Act of 1995. This press release contains
'forward-looking statements,' including statements about the discovery,
development and commercialisation of products. Various risks may cause Xenova's
actual results to differ materially from those expressed or implied by the
forward looking statements, including: adverse results in our drug discovery and
clinical development programs; failure to obtain patent protection for our
discoveries; commercial limitations imposed by patents owned or controlled by
third parties; our dependence upon strategic alliance partners to develop and
commercialise products and services; difficulties or delays in obtaining
regulatory approvals to market products and services resulting from our
development efforts; the requirement for substantial funding to conduct research
and development and to expand commercialisation activities; and product
initiatives by competitors.  For a further list and description of the risks and
uncertainties we face, see the reports we have filed with the Securities and
Exchange Commission.  We disclaim any intention or obligation to update or
revise any forward-looking statements, whether as a result of new information,
future events or otherwise.

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