Oncologic Response and Hospitalization Rate of Patients Receiving Cabazitaxel in the Fourth-Line and Beyond in Castration-Resistant Prostate Cancer: Analysis of a Retrospective Cohort and a Structured Literature Review

BACKGROUND: Limited data are available for the use of agents in metastatic castration-resistant prostate cancer (mCRPC) beyond the third-line. We provide data during treatment with cabazitaxel (CAB), helping to improve the informed-consent process. PATIENTS AND METHODS: We retrospectively reviewed patients treated with fourth-line or beyond CAB for mCRPC after failure of previous therapies with docetaxel, abiraterone acetate, enzalutamide and/or radium-223. The progression-free survival (PFS) and the overall survival (OS) were estimated using the Kaplan-Meier method and compared to published data based on a structured literature review. The hospitalization rate was recorded. Factors influencing 6-months OS were analyzed. RESULTS: Fifteen patients were identified at 4 institutions and included in the analysis. The median PFS was 104 days (range 47-397 days). The median time to death was 10 months (range 2-16). PFS and OS data are in accordance with 17 published patients so far. During the therapy, eleven (73%) of the patients were hospitalized. Prostate-specific antigen (PSA, 500 units; hazards ratio [HR] 1.491, 95% CI 1.000-2.0175), white blood cell count (HR 0.425, 95% CI 0.108-0.952), hemoglobin (HR 0.6014, 95% CI 0.2942-1.0758), and alkaline phosphatase (100 units; HR 1.0964, 95% CI 1.000-1.2859) correlate with 6-months OS. CONCLUSIONS: CAB beyond the third-line is often accompanied by hospitalization. PFS is a significant proportion of the median time of OS. The baseline laboratory might be a good indicator for the decision between CAB and best-supportive care.