Efficacy of cabazitaxel treatment in metastatic castration resistant prostate cancer in second and later lines. An experience from two German centers

Purpose: Several new treatment options for patients with metastatic castration resistant prostate cancer (mCRPC) have been approved within the last years - among them cabazitaxel (CAB), abiraterone acetate, enzalutamide, and radium-223. The aim of this study was to assess factors predictive for efficacy of CAB. Methods: We analyzed all patients with mCRPC treated with CAB at our institutions between 2011 and 2016. Data were retrieved retrospectively from the electronical patient chart. Results: 69 patients received CAB (26.1% 2^nd line, 36.2% 3^rd line, 37.3% > 3^rd line). Median overall survival (OS) on CAB was 10.0 months (95%CI 7.1-12.9). Median progression free survival (PFS) on CAB was 3.9 months (95%CI 3.0-4.8). There were no differences in OS and PFS regarding treatment line of CAB (2^nd vs. higher; 2^nd/3^rd vs. higher). Duration of remission on 1^st line treatment (> 6 months vs. </= 6 months) was associated with a longer PFS with subsequent CAB treatment (4.1 months vs. 3.0 months (95%CI 3.0-5.2; 2.2-3.8); p=0.021). Patients with visceral metastases had a shorter PFS (3.0 months; 95%CI 2.6-3.3) and OS (8.7 months; 95%CI 5.9-11.5) on CAB compared to patients who had bone and/or lymph node lesions only (PFS: 5.8 months; 95%CI 3.2-8.4; p=0.014; OS: 11.7 months; 95%CI 7.5-15.9; p=0.042). Conclusions: Results from our patient cohort suggest that a longer PFS to any 1^st line treatment for mCRPC is correlated with a longer PFS to CAB for any later line treatment. Patients with nodal and bone metastases only had a significantly superior PFS and OS with CAB treatment than patients with visceral metastases.