( BW)(DIATOS) Diatos Announces Acquisition of Specialty Cancer Product
DaunoXome(R) from Gilead Sciences

    Pharmaceutical Writers/Business Editors/Biotech Writers

    PARIS--(BUSINESS WIRE)--May 11, 2006--

        DaunoXome (liposomal daunorubicin) is indicated for the
   treatment of advanced HIV-related Kaposi's sarcoma and regulatory
        applications will be filed for Acute Leukemia in Europe

    Diatos SA, a Paris-based international biopharmaceutical company
focusing on the research and development and commercialization of
targeted anti-cancer therapies, announced today an exclusive licensing
agreement with Gilead Sciences, Inc. on the worldwide development and
commercialization rights to DaunoXome. DaunoXome is a marketed
liposomal formulation of daunorubicin, which has been approved for
AIDS/HIV-related Kaposi's sarcoma and is sold by Gilead in more than
20 countries. DaunoXome has also been evaluated in clinical studies
for potential efficacy and safety in acute myeloid leukemia (AML).
Daunorubicin is a widely used chemotherapeutic agent used principally
in hematological malignancies.
    Under the terms of the agreement, Diatos was granted exclusive
worldwide development and commercialization rights to DaunoXome in
Kaposi's sarcoma as well as all other potential indications. In
exchange, Gilead will receive upfront and milestone payments of up to
$4.7 million, based on regulatory approval of new indications, and
royalties on net sales.
    On the basis of data derived from DaunoXome's commercial use and
from various clinical studies in acute leukemic diseases, Diatos
intends to seek approval from European regulatory authorities for the
use of DaunoXome in acute leukemia. Acute myeloid leukaemia (AML) in
particular is a common form of blood cancer affecting more than 12,000
new patients per year in Europe. Diatos intends to continue to market
DaunoXome in Kaposi's sarcoma in Europe and Brazil.
    John Tchelingerian, PhD, President and CEO of Diatos, commented:
"The acquisition of DaunoXome is a significant milestone to accelerate
Diatos' transformation into an integrated European cancer
biopharmaceutical company with commercial capabilities." "We are very
pleased to acquire DaunoXome and expand its therapeutic spectrum in
acute leukemia, an area with high unmet medical needs", Dr
Tchelingerian added.

    Notes to Editors:

    About DaunoXome

    DaunoXome is a liposomal formulation of daunorubicin, a widely
used oncology chemotherapeutic agent. Daunorubicin is a
chemotherapeutic agent of the anthracycline class used to treat a
large number of hematological cancers, among which acute leukemia.
However, systemic administration of daunorubicin may lead to severe
cardiotoxic and hematotoxic unwanted side effects, which drastically
limit administered doses.
    DaunoXome's liposomal formulation has been developed to improve
the pharmacokinetic properties of daunorubicin. By enabling a
sustained release of active daunorubicin, it allows for the
administration of significantly higher doses of daunorubicin without
triggering more severe side effects.
    Since its initial clinical development in Kaposi's sarcoma,
DaunoXome has undergone extensive clinical trials in leukemia
patients, either sponsored by Gilead or by independent investigators.
In these trials, DaunoXome may present a better pharmacokinetic
profile as well as an improved tolerance versus the non liposomal form
of daunorubicin currently used as a standard treatment, which has led
to its off-label use for this patient group. In January 2006, Gilead
together with independent investigator groups completed a Phase III
clinical trial suggesting a better long term clinical outcome in
elderly AML patients receiving DaunoXome compared to those receiving
daunorubicin as first line treatment.

    About Kaposi's Sarcoma

    Kaposi's sarcoma is a virus-induced cancer in which tumor cells,
as well as abnormal growth of blood vessels, form solid lesions in
connective tissue. The dominant form is AIDS/HIV-related and it
represents approximately 80% of all forms of this cancer.

    About Acute Leukemia

    Leukemia is cancer of the blood and the blood-forming bone marrow,
characterized by an uncontrolled growth of bone marrow stem cells,
whose DNA has sustained acquired genetic damage. Acute Myelogenous (or
Myeloid) Leukemia, also called AML, is the most common type of acute
leukemia in adults and can also occur in children. Anthracycline-based
chemotherapy is the mainstay of treatment for the majority of
leukemias.

    About Diatos S.A.

    Diatos is a product-driven biopharmaceutical company dedicated to
the research, development and commercialization of novel anti-cancer
therapies with enhanced tumor targeting or improved biodistribution.
Diatos is expanding its portfolio of drug candidates with new
compounds that utilize its Vectocell(R) delivery technology or its
Tumor-Selective Prodrug (TSP) technology as well as with in-licensed
candidate cancer therapies. Diatos is headquartered in Paris, France
and operates subsidiaries in Belgium and the United States of America.
    For more information on Diatos, please visit its website at
www.diatos.com.

    The Diatos logo and Vectocell(R) are trademarks of Diatos S.A.

    About Gilead Sciences, Inc. (Nasdaq: GILD)

    Gilead Sciences is a biopharmaceutical company that discovers,
develops and commercializes innovative therapeutics in areas of unmet
medical need. The company's mission is to advance the care of patients
suffering from life-threatening diseases worldwide. Headquartered in
Foster City, California, Gilead has operations in North America,
Europe and Australia.

    Product-related Inquiries:

    Gilead Sciences, Inc. 

    Lawrence Vallandigham (Project Management), +1-650-522-5786,
Email: Lawrence.vallandigham@gilead.com

    For more information on Gilead Sciences, please visit the
company's website at www.gilead.com or call Gilead Public Affairs at
1-800-GILEAD-5 or 1-650-574-3000.

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    General Inquiries:
Diatos S.A.
John Tchelingerian, Ph.D., President & CEO    
c/o Mrs. Virginie Leplat, HR and Administrative Manager & Personal
Assistant to the CEO
Tel.: +33-(0)1-53-80-93-80, Email: vleplat@diatos.com
or
c/o Guillaume Dussert, Communications & Marketing Project Manager  
Tel.: +33-(0)1-53-80-93-83, Email: gdussert@diatos.com
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