9-Nitrocamptothecin as second line chemotherapy for men with progressive, metastatic, hormone refractory prostate cancer: Results of the CALGB 99901

Background: Institution of early hormone therapy in the PSA era coupled with demonstration of clinical benefit with chemotherapy in hormone refractory prostate cancer (HRPC) and acceptance of PSA decline as a surrogate for response has resulted in introduction of chemotherapy earlier in the natural history of disease. There now exists a need to identify, effective agents for second line chemotherapy. 9-Nitrocamptothecin (9-NC) a novel, oral camptothecin analogue was tested as second line chemotherapy for patients with progressive hormone refractory prostate cancer. Patients and Methods: Eligible patients had metastatic hormone refractory prostate cancer with performance status (0-1) following progression on at least 1 prior cytotoxic chemotherapy. 9-NC was administered orally at the dose of 1.5 mg/m²/d for 5 days each week for 3 weeks, followed by rest for 1 week. Response was evaluated after 2 cycles according to the guidelines set forth for Phase II trials in HRPC by the PSA working group. Results: Thirty-five patients were recruited to the study within a period of 6 months; 33 were evaluable for analysis. No patients had a >50% decline in PSA levels. Two out of 8 (25%) patients with measurable disease and 5/25 (20%) patients with nonmeasurable disease showed stable disease. The median time to disease and PSA progression was 2 months [95% confidence interval (CI), 0.9-2.8]. The median overall survival was 10 months (95% CI = 5-12). Seven patients are alive after a median follow-up of 23 months. Conclusions: 9-Nitrocamptothecin failed to elicit clinical or PSA responses. Further study in pretreated HRPC patients is not warranted.