Real-world treatment with abiraterone acetate in patients with chemotherapy-naive metastatic castration-resistant prostate cancer (mCRPC).

Abstract

239 Background: In the COU-AA-302 trial, abiraterone acetate plus prednisone (AAP) resulted in extension of radiographic progression-free survival (rPFS) and overall survival in chemotherapy-naïve mCRPC patients compared to prednisone alone. However, limited data on AAP treatment and outcomes is available in the real-world in this setting. The aim of this study is to describe the duration of AAP treatment in routine clinical practice in mCRPC patients prior to chemotherapy. Methods: The study was designed as a retrospective chart review of mCRPC patients identified through oncology and urology practice in Belgium, France, Germany and the UK. This first analysis reports baseline patient characteristics at AAP initiation for the first 224 patients. Treatment duration, PFS and rPFS were estimated using Kaplan-Meier curves. Potential factors associated with treatment duration were explored using the log-rank test. Results: Data from 224 mCRPC patients treated with AAP (Belgium: 67; Germany: 150; UK: 7; none from France) across 19 centres was considered in this initial analysis. At baseline, the median age was 75.5 years (interquartile range [IQR]: 69.0-82.0) and the median PSA level was 50.0 ng/mL (IQR: 21.0-121.0). Patients with visceral metastases (9.8%) and ECOG 2-3 (9.4%) were included in this study, in contrast to those included in the COU-AA-302 study. Median duration of AAP treatment was 11.6 months (95% confidence interval [CI]: 10.2-12.8), whilst median PFS and rPFS were 11.9 months (95% CI: 10.8-13.3) and 16.5 months (95% CI: 13.5-20.0), respectively. Reasons for discontinuing AAP involved PSA progression (52.2%), radiographic progression (38.9%), symptomatic progression (27.8%), non-toxic death (19.4%) and toxicity (2.2%). Treatment duration was significantly longer in mCRPC patients with either baseline ECOG status 0, lower PSA, alkaline phosphatase, aspartate aminotransferase, or lactate dehydrogenase levels (p < 0.05). Conclusions: The results of this study suggest similar treatment duration and rPFS for mCRPC patients in this real-life cohort with poorer clinical features compared to those observed in the COU-AA-302 trial population.