Treatment Duration And Utilization Patterns In Metastatic Castration-Resistant Prostate Cancer Patients Receiving Enzalutamide Or Abiraterone Acetate.

229Background: Enzalutamide (ENZA) and abiraterone acetate (ABI) are approved hormonal therapies for men with metastatic castration-resistant prostate cancer (mCRPC). This study assessed real-world treatment duration and utilization patterns in patients receiving ENZA or ABI. Methods: Adult mCRPC patients initiating ENZA or ABI before or after cytotoxic chemotherapy were identified from the Truven MarketScan® claims database (2012–2015). The index date was the first initiation of ENZA or ABI; continuous insurance enrollment for ≥6 months prior to and ≥3 months after the index date was required. Treatment discontinuation was defined as a prescription gap of ≥45 days. Median treatment duration was estimated using Kaplan–Meier method. Treatment switching was defined as starting a new mCRPC-related therapy within 30 days before to 45 days after the discontinuation date. Analyses were separately conducted for chemo-naive and chemo-experienced patients. Results: The study included 3230 chemo-naive (ENZA 920; AB...