Docetaxel reintroduction in patients with metastatic castration‐resistant docetaxel‐sensitive prostate cancer: a retrospective multicentre study

OBJECTIVE: To investigate the potential benefit of reintroducing docetaxel chemotherapy in patients with progressive metastatic castration-resistant prostate cancer (mCRPC) who had initially responded to first-line docetaxel-based regimen. PATIENTS AND METHODS: Records were evaluated retrospectively from French patients with mCRPC who had been included in seven controlled clinical studies of docetaxel as first-line treatment. We identified patients who were confirmed as responders to first-line treatment, discontinued for reasons other than disease progression or unacceptable toxicity, and who received further docetaxel chemotherapy for disease progression. The primary objective was to assess efficacy in terms of the prostate-specific antigen (PSA) response after resuming a docetaxel-based chemotherapy. Secondary objectives were overall survival and tolerance. RESULTS: Of the 148 patients who responded to first-line docetaxel, 50 received further therapy with docetaxel and were analysed. The median (range) response duration to first-line docetaxel was 10.3 (4.6-45.7) months and the median docetaxel-free interval was 18.4 (5.0-46.7) months. Docetaxel was reintroduced as second-line therapy in 52% of patients and as further lines in 48%. After docetaxel reintroduction, 24 patients (48%) had a 50% decrease in PSA level (95% confidence interval, CI, 34.1-61.8%). The median (95% CI) overall survival from docetaxel reintroduction was 16 (13-20) months. Re-treatment was well tolerated (6% of grade 3-4 haemotoxicity). CONCLUSION: Docetaxel reintroduction appears to be effective, with favourable tolerance profiles, in patients with mCRPC having responded to first-line docetaxel, and should be prospectively assessed in clinical trials against alternative therapies or investigational agents given alone or in combination, to define further management.