GPC Biotech Opens Enrollment in Phase 1 Trial Evaluating RGB-286638 Multi-Targeted Protein Kinase Inhibitor in Patients with Advanced Solid Tumors

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Martinsried/Munich (Germany), and Princeton, N.J., December 9, 2008 -
GPC Biotech AG (Frankfurt Stock Exchange: GPC; NASDAQ: GPCB) today
announced that enrollment has opened in a Phase 1 study evaluating
RGB-286638 in patients with advanced solid tumors. This is the first
time that this novel drug candidate is being studied in human
clinical trials.

The Phase 1 trial is an open label study being conducted at Erasmus
University Medical Center, Rotterdam, The Netherlands under the
direction of M.J.A. de Jonge, M.D., Ph.D. The objectives of this
study are to evaluate the safety and tolerability and to determine
the maximum tolerated dose and recommended Phase 2 dose and schedule
for RGB-286638 in patients with advanced solid tumors. The trial is
expected to enroll up to approximately 48 patients.

Dr. de Jonge said: "We are pleased to have the opportunity to be the
first site to test RGB-286638 in the clinic. Patients in the
advanced stages of cancer are in urgent need of new treatments. The
pre-clinical profile of RGB-286638 is compelling and justifies
clinical testing."

"We are excited to move RGB-286638 into clinical development," said
Martine George, M.D., Senior Vice President, Drug Development and
Chief Medical Officer of GPC Biotech. "Dr. de Jonge and her
colleagues at Erasmus University are highly respected for their
excellent work in cancer research, and we are pleased to have the
opportunity to work with them."

About RGB-286638
RGB-286638 is a multi-targeted protein kinase inhibitor entering
Phase 1 clinical testing. The RGB-286638 compound has been shown in
cancer cells to lead to the inhibition of cell cycle progression, the
process that controls cell division and ensures the accurate
duplication of genetic material, by targeting all relevant
cyclin-dependent kinases, which are proteins involved in regulating
the cell cycle. RGB-286638 has also been shown to induce apoptosis
(programmed cell death) and to inhibit other major protein kinases
that are important for the proliferation of cancer cells. In a range
of pre-clinical models of solid and hematological tumors, RGB-286638
treatment results in tumor regression and increased survival.

About GPC Biotech
GPC Biotech AG is a publicly traded biopharmaceutical company focused
on anticancer drugs. GPC Biotech's lead product candidate is
satraplatin, an oral platinum compound. The Company has various
anti-cancer programs in research and development that leverage its
expertise in kinase inhibitors. GPC Biotech AG is headquartered in
Martinsried/Munich (Germany) and has a wholly owned U.S. subsidiary
in Princeton, New Jersey. For additional information, please visit
GPC Biotech's Web site at www.gpc-biotech.com.

This press release contains forward-looking statements, which express
the current beliefs and expectations of the management of GPC
Biotech. Such statements are based on current expectations and are
subject to risks and uncertainties, many of which are beyond our
control, that could cause future results, performance or achievements
to differ significantly from the results, performance or achievements
expressed or implied by such forward-looking statements. Actual
results could differ materially depending on a number of factors, and
we caution investors not to place undue reliance on the
forward-looking statements contained in this press release. There can
be no guarantee that RGB-286638 will be successfully developed. We
direct you to GPC Biotech's Annual Report on Form 20-F for the fiscal
year ended December 31, 2007 and other reports filed with the U.S.
Securities and Exchange Commission for additional details on the
important factors that may affect the future results, performance and
achievements of GPC Biotech. Forward-looking statements speak only as
of the date on which they are made and GPC Biotech undertakes no
obligation to update these forward-looking statements, even if new
information becomes available in the future.

For further information, please contact:

GPC Biotech AG
Investor Relations & Corporate Communications
Phone: +49 (0)89 8565-2693
ir@gpc-biotech.com

In the U.S.: Laurie Doyle
Director, Investor Relations & Corporate Communications
Phone: +1 609-524-5884
usinvestors@gpc-biotech.com

Additional media contacts for Europe:
MC Services AG
Phone: +49 (0) 89 210 228 0

Raimund Gabriel
raimund.gabriel@mc-services.eu

Hilda Juhasz
hilda.juhasz@mc-services.eu

Additional investor contact for Europe:
Trout International LLC
Lauren Rigg, Vice President
Phone: +44 207 936 9325
lrigg@troutgroup.com

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GPC Biotech AG
Fraunhoferstr. 20 Martinsried Germany

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