Response to docetaxel/carboplatin in patients with hormone-refractory prostate cancer not responding to taxane-based chemotherapy

Few treatment options are available for patients with metastatic hormone-refractory prostate cancer (HRPC) that is not responsive to or continues to progress after taxane-based chemotherapy. Although single-agent carboplatin has modest activity in HRPC, carboplatin chemotherapy could induce a synergistic effect when combined with taxanes in patients with disease resistant to taxane-based chemotherapy. We report a case series of 4 consecutive patients treated with docetaxel (60-70 mg/m²) plus carboplatin (area under the curve of 4/5) following progression after taxane-based chemotherapy. Prostate-specific antigen levels decreased by > 50% in all 4 patients and were associated with improvement in symptoms in 3 of 4 patients. Treatment was well tolerated, with fatigue as the most common reported side effect. Patients received 4-11 cycles of treatment and, after initiation of docetaxel/carboplatin chemotherapy, survival ranged from 4.5 months to 12 months. In this small series, there is a suggestion of a greater than expected response with carboplatin and docetaxel for patients who exhibit disease progression despite taxane-based chemotherapy or do not respond to therapy. A clinical trial to evaluate this effect has been initiated.