Collaborative Agreement

Sareum Holdings PLC
10 January 2006


For immediate release                                          10th January 2006



                              SAREUM HOLDINGS PLC

                          ("Sareum" or the "Company")

            HIV/AIDS Collaboration with Idenix Pharmaceuticals, Inc.

Sareum Holdings plc (AIM: SAR), the specialist structure-based drug discovery
and services business, is pleased to announce that it has entered into a
collaborative agreement with Idenix Pharmaceuticals, Inc (Idenix). Idenix is
based in Cambridge, Mass, USA, and is engaged in the discovery and development
of innovative anti-viral therapeutics.

Sareum will utilise its expertise and skills in high throughput protein
expression, purification and structure determination to provide support for
Idenix's program to discover new drug candidates for the treatment of patients
with HIV/AIDS. Sareum will seek to illustrate the precise nature and manner in
which Idenix's potential drug candidates interact with an HIV virus protein that
is thought to be responsible for the development of viral resistance to many
currently approved HIV/AIDS therapies.

In return, Sareum will receive research fees and success milestone payments, the
majority of which are expected to be recognized in the financial year to June
2006. Financial terms of the agreement were not disclosed.

This announcement follows the trading update issued by Sareum on 5th January
2006 where the Company stated that it had entered into several collaborations in
late December, one of which is Idenix.

Commenting on the agreement, Sareum's Chief Executive Officer, Dr Tim Mitchell,
said: "We are delighted that Idenix has chosen Sareum as their partner for
protein structure determination. This collaboration, which is in an important
new area of medicine to Sareum, validates the flexibility of our technology
platform. Our track record in securing collaborations such as this demonstrates
we are a partner of choice for high-throughput protein structure determination."


For further information please contact:

Sareum Holdings                                                   01223 497700
Tim Mitchell, Chief Executive Officer

Buchanan Communications                                          020 7466 5000
Tim Anderson, Mary-Jane Johnson

About Sareum Holdings plc
Sareum Holdings plc is a specialist structure based drug discovery and services
business headquartered in Cambridge, UK. The Company was formed in August 2003
to discover new drugs for the treatment of cancer and to provide a range of drug
discovery services to the pharmaceutical industry. Sareum's unique approach aims
to halve the time it takes to discover new drug candidates.

Structure-based drug discovery involves the determination of a disease causing
protein's three-dimensional structure. Once the structure is known, novel
chemical entities are designed to 'lock-in' to the protein with the aim of
reversing or arresting a disease's progression.

Sareum's approach to structure based drug discovery is to produce multiple
recombinant proteins primarily through a baculovirus expression system;
determine their structure using x-ray crystallography; and then use its
innovative template-molecule x-ray screening technology to identify new chemical
entities designed to interact with the target protein. Sareum then uses its
high-throughput medicinal chemistry platform to rapidly synthesise further
molecules and develop the most promising into potential drug candidates.

Sareum provides its specialist drug discovery capabilities to partners in the
pharmaceutical and biotechnology industries. The Company aims to successfully
deliver: Programmes for complete gene-to-candidate structure-based discovery;
projects to accelerate or improve the productivity of specific activities; and
drug candidates for licensing at the Phase I or Phase II clinical trials stage.

Sareum joined the AIM Market of the London Stock Exchange in October 2004 and
trades under the symbol SAR. For further information, please visit
www.sareum.co.uk

About Idenix
Idenix Pharmaceuticals, Inc. is a biopharmaceutical company engaged in the
discovery and development of drugs for the treatment of human viral and other
infectious diseases. Idenix current focus is on the treatment of infections
caused by hepatitis B virus, hepatitis C virus and human immunodeficiency virus
(HIV).

About HIV/AIDS
AIDS, acquired immunodeficiency syndrome, is caused by the human
immunodeficiency virus, or HIV. HIV destroys the body's ability to fight
infections by attacking cells of the immune system.

Very soon after an individual becomes infected, the virus is spread throughout
the body and reproduces itself at extremely rapid rates. As this happens, the
immune system detects the virus and makes antibody, usually within two to four
weeks of infection. The lymph system consists of nodes throughout the body that
contain immune cells (T-lymphocytes) that trap, attack and destroy HIV (and
other unwanted microbes). Eventually the cells in the lymph node become
themselves infected and the lymph nodes begin to break down. This destruction of
the nodes allows HIV and any other viruses, bacteria and fungi to "spill over"
into the blood stream and attack more cells throughout the body. The destruction
of infected lymphocytes by HIV eventually becomes so great that the
T-lymphocytes are destroyed faster than they can be replaced, leading to a
markedly weakened immune response. At this point, clinical symptoms of HIV
appear, which include opportunistic infections and cancers, a sign that the
disease is in an advanced stage. This entire course of events varies in duration
among individuals, but when untreated usually lasts about 12 years.

Although efforts to develop a vaccine have failed to yield promising results,
the significant investment in research has led to the development of a number of
drugs to treat HIV infection.

In the United States and Western Europe where there is generally broader access
to HIV drug therapy, many patients have developed drug resistant HIV rendering
multiple drugs ineffective. Resistance can develop whenever there is less than
complete suppression of virus replication (100% efficacy), a goal that has not
yet been achieved. Factors that contribute to lack of 100% efficacy include:
sub-optimal potency of the treatment regimen, pharmacokinetics or drug
interactions, and side effects and poor tolerance to therapy which can lead to
less than optimal adherence to the complex regimens required for HIV treatment.

HIV/AIDS Infection - Global Impact

   •40 million people worldwide are living with HIV infection or AIDS
   •2.5 million children are infected with HIV
   •Approximately 21.8 million people have died from AIDS
   •HIV/AIDS resulted in approximately 3.0 million deaths in 2003




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