Overall survival in patients with metastatic castration-sensitive prostate cancer treated with apalutamide versus abiraterone acetate: a head-to-head analysis of real-world patients in the USA.

Aim: Head-to-head studies of survival outcomes associated with different androgen receptor pathway inhibitor (ARPI) treatments for metastatic castration (hormone)-sensitive prostate cancer have not been conducted. The purpose of this study was to compare 24-month overall survival among ARPI-naive patients with metastatic castration-sensitive prostate cancer (mCSPC) who initiated apalutamide or abiraterone acetate. Materials & methods: Linked de-identified clinical and claims healthcare databases were used to compare overall survival between patients with mCSPC initiating apalutamide or abiraterone acetate treated in community-based urology practices in the USA. Overall survival at 24 months post-treatment initiation (primary analyses) was compared between apalutamide and abiraterone acetate initiators using weighted Cox proportional hazards models (exploratory analyses used all available follow-up). Results: Overall, 1879 and 2073 patients had initiated apalutamide or abiraterone acetate, respectively (both cohorts: weighted mean age 72 years, 62% were white, and 66% had bone metastasis). At 24 months post-index, patients in the apalutamide cohort had a 26% lower risk of mortality compared with those in the abiraterone acetate cohort (hazard ratio: 0.74; 95% confidence interval: 0.59, 0.93; p = 0.010), with the difference maintained when outcomes were evaluated using all available follow-up (hazard ratio: 0.72; 95% confidence interval: 0.59, 0.88; nominal p < 0.001). Conclusion: In this nationally representative, real-world head-to-head analysis of nearly 4000 ARPI-naive patients with mCSPC, apalutamide was associated with a 26% reduction in the risk of mortality compared with abiraterone acetate by 24 months post-treatment initiation.