Apalutamide for metastatic castration-sensitive prostate cancer: final analysis of the Asian subpopulation in the TITAN trial

Abstract

The final analysis of the phase 3 Targeted Investigational Treatment Analysis of Novel Anti-androgen (TITAN) trial showed improvement in overall survival (OS) and other efficacy endpoints with apalutamide plus androgen deprivation therapy (ADT) versus ADT alone in patients with metastatic castration-sensitive prostate cancer (mCSPC). As ethnicity and regional differences may affect treatment outcomes in advanced prostate cancer, a post hoc final analysis was conducted to assess the efficacy and safety of apalutamide in the Asian subpopulation. Event-driven endpoints were OS, and time from randomization to initiation of castration resistance, prostate-specific antigen (PSA) progression, and second progression-free survival (PFS2) on first subsequent therapy or death. Efficacy endpoints were assessed using the Kaplan–Meier method and Cox proportional-hazards models without formal statistical testing and adjustment for multiplicity. Participating Asian patients received once-daily apalutamide 240 mg (n = 111) or placebo (n = 110) plus ADT. After a median follow-up of 42.5 months and despite crossover of 47 placebo recipients to open-label apalutamide, apalutamide reduced the risk of death by 32% (hazard ratio [HR]: 0.68; 95% confidence interval [CI]: 0.42–1.13), risk of castration resistance by 69% (HR: 0.31; 95% CI: 0.21–0.46), PSA progression by 79% (HR: 0.21; 95% CI: 0.13–0.35) and PFS2 by 24% (HR: 0.76; 95% CI: 0.44–1.29) relative to placebo. The outcomes were comparable between subgroups with low- and high-volume disease at baseline. No new safety issues were identified. Apalutamide provides valuable clinical benefits to Asian patients with mCSPC, with an efficacy and safety profile consistent with that in the overall patient population.