840P - Prognostic value of free testosterone (FT) levels during salvage chemotherapy with carboplatin plus weekly docetaxel in metastatic castration- and docetaxel-resistant prostate cancer (mDRPC)

Abstract

ABSTRACT Background Recent data suggest that carboplatin plus weekly docetaxel (DC) is an effective salvage therapy in DRPC. Carboplatin, docetaxel and steroids all interfere with testosterone biosynthesis and/or metabolism. In this study the impact of DC treatment on testosterone serum levels was analyzed. Methods Docetaxel failure/resistance was defined according to the Prostate Cancer Working Group (PCWG2 2007) criteria. Since February 2005, 71 consecutive DRPC pts were treated with at least two cycles of carboplatin AUC5 iv for 30 min on day 1 every 4 weeks (q4w), docetaxel at a dose of 35 mg/m iv for one hour on days 1, 8, (15) plus prednisone 2x5mg/day orally after receiving informed consent until disease progression or occurrence of intolerable adverse effects. Efficacy measures were done following PCWG2 recommendations. FT was measured before (n = 44) and during carboplatin/docetaxel chemotherapy (n = 38). Results Response of prostate-specific antigen (PSAR; ≥50% PSA) was observed in 34/71 (47.9%) patients. At the time of the current analysis the median follow-up time was 14.5 months and 47/71 patients had died. Median progression-free survival (PFS) for all patients was 6.9 months (CI 95% 4.3, 13.6) and median overall survival (OS) was 18.0 months (CI 95% 10.4, 25.6). Median FT serum levels were 3.0 pmol/L before (n = 43) and below the RIA detection limit of Conclusion These data demonstrate for the first time that testosterone is an important prognostic factor for PFS and OS in mDRPC patients receiving chemotherapy. Disclosure C.W.M. Reuter: Minor consulting fees from Sanofi Aventis, Amgen, V. Grunwald: Consulting fees from Novartis, All other authors have declared no conflicts of interest.