Sequencing of cabazitaxel and abiraterone acetate following docetaxel in metastatic castration-resistant prostate cancer (mCRPC).

Abstract

79 Background: Following docetaxel (D), treatment options for mCRPC include cabazitaxel (CBZ), abiraterone acetate (AA), and enzalutamide. With the introduction of new agents, optimal sequencing is undefined. We evaluated the prevalence of sequencing of AA and CBZ following D in a large community-based cohort to develop a hypothesis for the most optimal sequence. Methods: A retrospective analysis of treatment patterns using the MSH iKnowMed EHR was conducted. Post-D mCRPC patients receiving CBZ and/or AA at full EHR sites with ≥2 visits were included; clinical trial patients excluded. CBZ utilization between Jun’10 and May’12 and sequencing of CBZ or/and AA from Apr’11 and May’12 (when both drugs were available) were examined. OS, time to treatment failure (TTF), and demographics analyses are ongoing. Results: 667 evaluable patients were identified. Overall CBZ (n=359 pts/2 y) utilization declined between Jun’10-May’11 (n=232) and Jun’11-May’12 (n=127). From Apr’11 to May’12: overall AA (n=465 pts/y) utilization increased between Mar-May’11 (n=73) to Jun-Aug’11 (n=164) and subsequently decreased (n=57) from Mar-May’12. Between Apr’11-May’12, 130 patients received both CBZ and AA. More men (P<0.001) received D→CBZ→AA (n=88, 67.7%) compared with D→AA→CBZ (n=42, 32.3%). Median age of patients receiving both CBZ and AA was 67 (44-89) y and their median baseline PSA (111 evaluable) was 84.3 (0.4-7672.2) ng/mL. Conclusions: AA was administered more frequently than CBZ in post-D mCRPC patients. However, the sequence of D→CBZ→AA was more prevalent than D→AA→CBZ in this large community-based cohort. Until predictive biomarkers and outcomes with respective sequences are identified, delivery of all active agents according to patient-specific clinical factors should probably be considered. [Table: see text]