Beyond ten cycles of cabazitaxel for castrate-resistant prostate cancer

Background: There are limited data regarding cabazitaxel use beyond 10 cycles. Patients and Methods: Retrospective analysis of prospectively collected data of patients with metastatic castrate-resistant prostate cancer who received over 10 cycles of cabazitaxel after docetaxel failure. Results: Four patients received between 14 and 27 cycles. Reasons for stopping cabazitaxel were toxicity (2), progression (1) and logistics (1). Two of the three patients with measurable disease attained a partial remission (PR). Three patients continued to have a PSA response after 10 cycles; PSA nadir occurred between 17 and 23 cycles. Other than peripheral neuropathy (PN), all the cabazitaxel-related toxicities occurred after the initial cycles and did not increase cumulatively. Clinically significant neuropathy occurred after 15-17 cycles. The cabazitaxel-induced PN was partially reversible, with improvement from grade 3 to grade 2 after a 3-5-month long drug holiday. Conclusion: Cautiously continuing cabazitaxel until progression or intolerable toxicity may maximize efficacy.