A prospective study of carboplatin-etoposide in docetaxel-pretreated patients with hormone-refractory prostate cancer (HRPC): Clinical activity and correlation with neuroendocrine features

Abstract

5151 Background: There is currently no standard of care for patients (pts) with HRPC and disease progression after docetaxel-based chemotherapy. Platin compounds have demonstrated activity in this setting and in vitro evidence of synergy between carboplatin and etoposide has previously been reported. A significant proportion of advanced HRPC exhibit neuroendocrine features but there are limited data on whether these patients should be treated differently or not. Methods: Pts with HRPC who experienced failure after first-line docetaxel-based chemotherapy were prospectively treated with carboplatin (AUC 5 day 1) and etoposide (80 mg/m2 day 1 to 3), repeated every 3 weeks as second-line chemotherapy. The response rate (defined as a serum PSA decline of = 50%), progression-free survival (PFS) and overall survival (OS) were evaluated using consensus criteria (Bubley JCO 1999). Pain relief was evaluated using a visual analogic scale. Serum chromogranin A and neurone specific enolase (NSE) levels were measured at baseline. Toxicity was evaluated according to NCI criteria. Results: Forty-one HRPC pts, previously treated with docetaxel with (n=24) or without (n=17) estramustine, prospectively received carboplatin-etoposide as second-line chemotherapy. A PSA response was obtained in 9 pts (22%). Pain relief was achieved in 18 pts (45%). Median progression-free survival was 9 weeks and median overall survival was 19 months. Toxicity included grade 3–4 anemia in 25% and febrile neutropenia in 2%. Biological neuroendocrine features (e.g. elevated baseline serum chromogranin A and NSE) were not associated with response or PFS. The response rate was 18% and 31% in pts with normal and elevated baseline chromogranin A, respectively. Conclusions: The carboplatin-etoposide regimen is active and well-tolerated as second-line chemotherapy after docetaxel-based chemotherapy in HRPC patients. Activity was detected in both tumors with and without neuroendocrine features. No significant financial relationships to disclose.