GPC BIOTECH/DEBIOPHARM SIGN MHC II ANTAGONISTS LICENSE PACT.

GPC Biotech AG (Frankfurt Stock Exchange: GPC; TecDAX 30; NASDAQ: GPCB) and Debiopharm S.A., the independent drug- development company specializing in oncology, endocrinology and niche products, have signed a license agreement for GPC Biotech's pre-clinical small molecule MHC class II antagonists program. Under the agreement, Debiopharm is licensing the exclusive worldwide rights to GPC Biotech's program for further development and will assume all future development costs. GPC Biotech will receive an upfront payment, milestone payments and royalties. Further financial details were not disclosed.

Bernd R. Seizinger, M.D., Ph.D., CEO of GPC Biotech said: "We are very pleased to partner this promising program for autoimmune diseases with such a reputable company. Debiopharm developed, for example, the blockbuster anticancer drug Eloxatin(r) (oxaliplatin) and has shown that it can bring drugs to the market successfully. While GPC Biotech has focused its internal development efforts on oncology, the partnering of this program also shows the value of our earlier research in other indications such as autoimmune diseases. There still is no treatment available that addresses the cause of diseases like rheumatoid arthritis and a large unmet medical need remains."

"This program offers an immense potential in chronic autoimmune diseases and our objective is to rapidly prove this concept and bring a meaningful new treatment to patients," said Rolland-Yves Mauvernay, president and CEO of Debiopharm. "GPC Biotech and Debiopharm have a good cultural and business fit and I am sure that this collaborative aspect will add to our efforts."

About GPC Biotech's small molecule MHC class II antagonists program outlicensed to Debiopharm:

The immune system distinguishes between foreign antigens and the body's own tissue, and normally only responds to the foreign antigens. The MHC class II molecule plays an important role in this process. It has been seen that susceptibility to autoimmune diseases like rheumatoid arthritis, where the immune system attacks the body's own tissue, is associated with specific genetic variants of the MHC class II molecule. GPC Biotech's program generated small molecules that selectively block these disease-associated MHC class II molecules while leaving the remainder of the immune system available for protective responses against pathogens. Therefore, these drugs may cause fewer immunocompromising side effects than most currently available immunosuppressive drugs, and they would represent a disease mechanism-based intervention, which is expected to interrupt the initial event that initiates the disease instead of treating its symptoms. GPC Biotech's small molecule MHC class II antagonists program was funded in part by a research grant of the German Ministry of Education and Research (Bundesministerium fuer Bildung und Forschung).

GPC Biotech AG is a biotechnology company discovering and developing new anticancer drugs. The company's lead product candidate - satraplatin - is currently in a Phase 3 registrational trial as a second-line chemotherapy treatment in hormone-refractory prostate cancer following successful completion of a Special Protocol Assessment by the U.S. FDA and receipt of a Scientific Advice letter from the European central regulatory authority, EMEA. The FDA has also granted fast track designation to satraplatin for this indication. Satraplatin was in-licensed from Spectrum Pharmaceuticals, Inc. Other anticancer programs in development include a monoclonal antibody and a cell cycle inhibitor. The company is leveraging its drug discovery technologies to elucidate the mechanisms-of-action of drug candidates and to support the growth of its drug pipeline. The company has formed successful alliances with a number of pharmaceutical and biotechnology firms. For example, the company has a multi-year alliance with ALTANA Pharma AG working with the ALTANA Research Institute in the U.S., which provides GPC Biotech with revenues until 2007. GPC Biotech AG is headquartered in Martinsried/Munich (Germany). The company's wholly owned U.S. subsidiary has research sites in Waltham, Massachusetts and Princeton, New Jersey.

For more information, visit http://www.gpc-biotech.com or call 781/890-9007, ext. 267.

Debio is an established group of four complementary companies, Debiopharm, Debioinnovation, Debio R.P. and Debioclinic. Debiopharm, founded in 1979 in Lausanne, Switzerland, focuses on evaluating compounds with promising in-vivo results in animals to in-license, develop for global registration, and out-license to sales and marketing pharmaceutical partners. Debiopharm has proven expertise in drug development, having registered three products: Eloxatin(r), one of Sanofi-Aventis' leading marketed products, Decapeptyl(r), the leading product of Ipsen, and Trelstar(r) (1-and 3-month). Together, their combined sales are in excess of $ 1.8 bn in 2004. Debioinnovation was set up to complement the core business objectives of Debiopharm through addressing the financing and partnering needs of biotechnology, pharmaceutical start-up companies and life science incubators. Debio R.P. is a leader in polymer-based controlled release technologies that allow certain drugs like proteins, peptides and anti-cancers to be delivered in customised, sustained-release formulation. From its FDA-inspected manufacturing facility in Martigny, Switzerland, Debio R.P. also conducts feasibility studies, formulation selection, optimization, scale-up and cGMP manufacturing from clinical trial supplies to commercial scale. Debioclinic is a contract research organization, specialized in oncology and dedicated to clinical development, providing regulatory, biometric and clinical support in line with cGCP.

For more information, visit http://www.debio.com.