Do Indian men have similar oncological outcomes with abiraterone plus androgen deprivation therapy in the setting of metastatic hormone-sensitive prostate cancer? A prospective observational study.

ABSTRACT

Introduction: Combination of abiraterone with androgen deprivation therapy (ADT) has better survival outcomes than ADT alone in metastatic Hormone-sensitive prostate cancer (mHSPC) in the Western population. In this prospective (Clinical Trials Registry-India [CTRI] registered) observational study, we present the comparative oncological outcomes of ADT alone and ADT + abiraterone in Indian patients, which is not available currently. Methods: This study (CTRI-number-CTRI/2020/07/026545) included newly diagnosed mHSPC patients from January 2020 to June 2023 in a tertiary care hospital, urology department. Patients fulfilling inclusion criteria were advised ADT with abiraterone (A + ADT), and those not affording received ADT monotherapy (ADT). The primary endpoint was overall survival (OS). Secondary outcomes included prostate-specific antigen (PSA) decline >90%, radiographic progression-free survival (rPFS), and PSA progression-free survival (pPFS). Results: Out of 278 patients with mHSPC, 163 patients were excluded and 115 were analyzed (ADT = 40 vs. A + ADT = 75). After a median follow-up of 20.3 months, 11 of 40 (27.5%) in ADT-only arm and 15 of 75 (20%) in ADT + abiraterone arm had died (Hazard-ratio of death 0.72; 95% confidence interval 0.68-0.88; P < 0.001). A PSA decline of >90% was seen in 85% in the ADT alone group and 93.3% in the ADT + abiraterone group. Significantly better outcomes of the ADT + abiraterone were seen in the secondary endpoints of rPFS (P < 0.001) and pPFS (P < 0.001). The OS benefit was 28% reduction in risk of death in our study versus 37% and 38% in STAMPEDE and LATITUDE, respectively. pPFS and rPFS were also poorer in Indian subsets. Conclusions: Abiraterone with ADT improves OS, PSA response, rPFS, and pPFS in the Indian population akin to the Western data but with poorer OS, rPFS, and PSA progression-free survival on comparison.