Treatment of androgen-independent, hormone-refractory prostate cancer with docetaxel in Japanese patients

Abstract

Although patients with prostate cancer with metastatic lesions initially respond to androgen ablation therapy, most patients ultimately develop a hormone-refractory state. Effective treatment for men with hormone-refractory prostate cancer (HRPC) has not been established. We performed a clinical study of docetaxel in HRPC patients, and evaluated its efficacy. Nine patients with HRPC were administered 55 mg/m2 docetaxel, every 3 weeks, simultaneously with hormonal therapy, with a luteinizing hormone-releasing hormone analog, and daily oral dexamethasone. Change in serum prostate-specific antigen (PSA) was determined as the primary endpoint. The mean age of the patients was 64 years (range, 49 to 76 years). Median follow-up time was 8.5 months (range, 5.3 to 16.7 months). In eight patients whose pretreatment serum PSA was elevated, six patients (75.0%) had a PSA decline of more than 50%, and four (50.0%) had a PSA decline of more than 75%. Median time to progression for all patients was 7.9 months (range, 0.0 to 11.6 months; 95% confidence interval [CI], 0.0 to 26.3). The median overall survival was 8.5 months (range, 5.3 to 16.7 months; 95% CI, 8.1 to 13.8). Four of six patients (66.7%) with pain before treatment obtained pain relief and were able to discontinue analgesic agents. This regimen was well tolerated. Grade 3 or 4 neutropenia or leukocytopenia without fever was seen in three patients (33.3%). Only one patient required administration of granulocyte-colony stimulating factor because of neutropenia. No other grade 3 or 4 toxicity was observed. Docetaxel was an active agent in Japanese HRPC patients, and was well tolerated in this population. To establish its efficacy and safety in Japanese HRPC patients, a large-scale study in Japan is warranted.