New Data from Several Satraplatin Clinical Trials in Solid Tumors Presented at 44th ASCO Annual Meeting

Business Wire, June 2, 2008

MARTINSRIED/MUNICH, Germany & PRINCETON, N.J. -- GPC Biotech AG (Frankfurt Stock Exchange: GPC, NASDAQ: GPCB) today announced the presentation of data from several satraplatin clinical trials at the 44th Annual Meeting of the American Society for Clinical Oncology (ASCO) in Chicago.

"We are pleased that data from several satraplatin clinical trials evaluating satraplatin in combination with a variety of widely used cancer treatments were selected for presentation at this year's ASCO Annual Meeting," said Bernd R. Seizinger, M.D., Ph.D., Chief Executive Officer of GPC Biotech. "The information gained from these studies is helpful to GPC Biotech and others as we plan new trials with this active oral platinum-based compound."

The following are summaries of the highlighted presentations.

Phase I study of satraplatin and docetaxel in solid malignancies - Ticiana B Leal, MD, (Abstract #2570)

The primary objective of this study was to determine the maximum tolerated dose (MTD) of satraplatin and docetaxel (Taxotere([R])) in patients with advanced solid tumors when docetaxel was administered every three weeks. Twenty-three patients were enrolled in the study. The patient population was heavily pre-treated, with a median of two prior cytotoxic chemotherapy regimens. The recommended Phase II dose was satraplatin at 40mg/m2/day given on days 1-5 and docetaxel at 60mg/m2 given on day 1 of a three-week cycle, without G-CSF, and satraplatin at 50mg/m2/day given on days 1-5 and docetaxel at 70mg/m2 given on day 1 of a three-week cycle with G-CSF. G-CSF is used to promote the recovery of white blood cells. The most commonly reported adverse event was neutropenia (decrease in white blood cells) in 22% of patients, followed by anemia, diarrhea and fatigue. Preliminary data show encouraging activity in men with high-grade androgen independent prostate cancer. As a result, this combination is currently being further explored in men with chemo-naive, androgen independent prostate cancer.

Phase I study of the oral platinum agent satraplatin in sequential combination with capecitabine in patients with advanced solid tumours - Cristiana Sessa, MD (Abstract #2560)

The primary objective of this study was to determine the MTD and Phase 2 recommended dose for satraplatin administered sequentially with capecitabine (Xeloda([R])). Thirty-seven patients with a variety of solid tumors were treated in the study. The MTD and recommended dose for Phase 2 was satraplatin at 70 mg/m2 and capecitabine at 1000 mg/m2/BID (twice daily). Hematological toxicity was the main dose-limiting toxicity. In the 34 patients who were evaluated, there were three confirmed partial responses - two in platinum-sensitive ovarian cancer and one in prostate cancer patients, as well as six stable disease in prostate cancer patients. These preliminary results suggest that the sequential administration of satraplatin and capecitabine may represent a well tolerated and convenient oral treatment for patients with advanced solid tumors.

Phase I study of oral platinum with concurrent radiation therapy in non small cell lung cancer - Hak Choy, MD (Abstract #7560)

The objectives of this study were to determine the dose-limiting toxicities, MTD and recommended Phase 2 dose of satraplatin in combination with radiation therapy for patients with non-small cell lung cancer (NSCLC). Fifteen patients were enrolled in the study. The recommended Phase 2 dose for this patient population is 30 mg/d each day of radiation treatment. Dose limiting toxicities were Grade 3 pneumonia and Grade 3 elevated liver function. Of the eleven evaluable patients, eight had partial responses and three had stable disease. These results suggest therapeutic synergy of satraplatin in combination with radiation for the treatment of NSCLC and provide a rationale for future studies with this combination.

Satraplatin in patients with advanced hormone-refractory prostate cancer: Overall survival results from the phase III satraplatin and prednisone against refractory cancer (SPARC) trial, A. Oliver Sartor, MD (Abstract #5003)

Data from this oral presentation are discussed in a separate press release issued by GPC Biotech on June 2, 2008.

Additional data on satraplatin and on RGB-286638 broad-spectrum kinase inhibitor published in ASCO Annual Meeting Proceedings

The Company also reported that data from two other satraplatin clinical trials, as well as in vitro data in multiple myeloma with the RGB-286638 kinase inhibitor, were published in the ASCO Annual Meeting Proceedings.

Cirstea, Diana et al, "Pleiotropic Activity of the Novel Cyclin-Dependent Kinase Inhibitor RGB 286638 Predicts Therapeutic Potential in Multiple Myeloma." Researchers assessed the effect of RGB-286638, a novel broad-spectrum kinase inhibitor, on inhibiting tumor growth in conventional drug-sensitive and drug-resistant multiple myeloma cell lines and primary tumor cells from multiple myeloma patients. The results demonstrated that RGB-286638 induces multiple myeloma cell death via the inhibition of cyclin-dependent kinase/cyclin complexes and cell cycle progression. In vivo studies are ongoing to assist in the design of clinical testing for RGB-286638 in multiple myeloma.