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

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. 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). 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. 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.