Satraplatin: A new treatment option for patients with hormone refractory prostate cancer

Abstract

4802 Background: There is no chemotherapeutic agent specifically approved for second-line treatment for hormone-refractory prostate cancer (HRPC). Satraplatin (S) is a third-generation oral platinum compound studied in a variety of tumors, including HRPC. Results of previous phase II and III trials suggested activity in HRPC. A randomized trial conducted by the EORTC in 50 patients evaluated S as first-line therapy in HRPC. The median progression-free survival (PFS) was longer in the satraplatin + prednisone (S + P) arm than in the P alone arm. This difference was statistically significant (p = 0.023). Furthermore, a >50% decrease from baseline PSA value was seen in 9 of 27 patients (33%) in the combination arm compared to 2 of 23 (9%) patients in the P arm (p = 0.046). We have initiated a randomized phase III trial evaluating S as second line therapy for HRPC. Methods: The primary objective is to compare time to tumor progression (TTP) and PFS in patients with HRPC, randomized to either S + P or placebo + P, after failure of 1 prior chemotherapy regimen. Eligible patients include men ≥ 18 years with stage D2 metastatic HRPC with progressive disease after a minimum of 2 courses of 1 prior cytotoxic chemotherapy regimen. The final analysis will be performed after 637 events of disease progression have been observed. Using a significance level of 0.034, the trial has 85% power to detect a 30% improvement in TTP. Results: Accrual is ongoing. Conclusions: Results of 2 studies, SWOG 99–16 and TAX327, demonstrated a survival advantage for the docetaxel-containing arm, and docetaxel is approved for use in HRPC. However, the duration and response to first line chemotherapy is limited, and there is an unmet medical need for agents that provide palliation and improve survival. S has demonstrated in vitro activity against taxane-resistant cell lines and significantly prolonged PFS for untreated HRPC patients in a randomized setting. These observations formed the scientific rationale for GPC Biotech to initiate an international multi-center, double-blind, randomized phase III trial comparing S + P to placebo + P as second-line cytotoxic therapy for men with HRPC. The trial is open and actively accruing patients. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration GPC Biotech AG, GPC Biotech GPC Biotech GPC Biotech GPC Biotech GPC Biotech