Efficacy of Cabazitaxel Treatment in Metastatic Castration Resistant Prostate Cancer in Second and Later Lines. An Experience from Two German Centers

Abstract

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.

Keywords: Cabazitaxel; castration resistance.; prostate cancer; sequencing therapy; survival.

Figure 1

a) Time between initiation of systemic LHRH treatment and the development of castration resistant disease was 35.0 months. b) PFS on 1^st line treatment independent of treatment type was 7.0 months.

Figure 2

a) Progression free survival (PFS) on cabazitaxel (CAB) as 2^nd or later line treatment; median PFS was 3.9 months. b) PFS on CAB stratified for PFS on 1^st line (≤ 6 months vs. > 6 months). Patients with PFS_{1st line} > 6 months had a significantly longer PFS on CAB in any later treatment line (4.1 months vs. 3.0; p=0.021). c) PFS of patients with visceral metastases was 3.0 compared to 5.8 months when no visceral metastases were present (p=0.014). d) Overall survival (OS) of patients with visceral metastases was 8.7 compared to 11.7 months in the absence of visceral metastases (p=0.042).