Randomized phase II study comparing paclitaxel and carboplatin versus mitoxantrone in patients with hormone-refractory prostate cancer

ObjectivesMitoxantrone/prednisone was the 2002 palliative reference treatment for hormone-refractory prostate cancer (HRPC). Paclitaxel and carboplatin has demonstrated antitumor activity in HRPC. The therapeutic benefit of such treatment was compared with that of mitoxantrone.MethodsA randomized Phase II study was conducted that included 40 patients with HRPC who had not undergone chemotherapy. Patients in arm A received paclitaxel (175 mg/m2 every 3-week cycle) and carboplatin (area under the curve of 5 every 3-week cycle). Patients in arm B received mitoxantrone (12 mg/m2 every 3-week cycle). All the patients treated were receiving low-dose prednisone. The primary endpoint was the prostate-specific antigen response.ResultsThe prostate-specific antigen response to paclitaxel and carboplatin was significantly greater (40% [95% confidence interval 18.5% to 61.5%] versus 10% [95% confidence interval 1% to 32%], P = 0.031) and more durable (8.6 versus 2 months, P = 0.015) than the response to mitoxantrone. A tendency was noted for patients with measurable disease who were receiving paclitaxel and carboplatin to have a somewhat greater objective response rate than those who received mitoxantrone (23% [95% confidence interval 5.3% to 55%] versus no objective response, P = 0.060). The median overall survival was 14.5 months for the paclitaxel and carboplatin arm compared with 11.1 months for the mitoxantrone arm. The group given paclitaxel and carboplatin had significantly greater rates of sensitive neuropathy (50% versus 0%, P = 0.00026).ConclusionsThe 3-week regimen of paclitaxel and carboplatin induced a greater and more durable prostate-specific antigen response than did mitoxantrone for HRPC treatment. The major additive toxicity induced was peripheral neuropathy due to paclitaxel. Investigations with paclitaxel and carboplatin regimens merit large Phase III studies.