Docetaxel rechallenge in metastatic castration-resistant prostate cancer: A retrospective, single-center study

PURPOSE: To assess the efficacy and safety of docetaxel rechallenge in the salvage setting in metastatic castration-resistant prostate cancer (mCRPC) patients. MATERIALS AND METHODS: Clinicopathologic data from patients treated with docetaxel rechallenge were collected from a single-center cancer registry. Among 227 patients who received first-line docetaxel for mCRPC between January 2011 and June 2019, 23 undergo rechallenge docetaxel after failure to androgen receptor targeting agents and/or cabazitaxel treatment. Endpoints included radiologic progression-free survival (PFS), treatment duration, and prostate-specific antigen (PSA) response and safety. RESULTS: Overall, 30%, 44%, 13%, and 13% of patients received docetaxel rechallenge as either the third, fourth, fifth, or sixth-line therapy, respectively, at a median of 23.6 months after stopping first-line docetaxel. With first-line docetaxel and rechallenge, median treatment duration was 6.4 and 3.3 months, respectively. With docetaxel rechallenge, PSA response was 35% (95% confidence interval [CI], 15% to 54%) and median PFS was 4.5 months (95% CI, 1.9 to 7.1 months). The median OS was 24.3 months (95% CI, 4.6 to 44.0 months). There were 7 severe adverse events (grade 3 or more) including anemia (8.7%), neutropenia, thrombocytopenia, leukopenia, diarrhea, and nausea (4.3% each). CONCLUSIONS: Docetaxel rechallenge showed meaningful anti-tumor activity with acceptable toxicity in heavily pretreated patients with mCRPC.