Apalutamide for patients with metastatic castration-sensitive prostate cancer in East Asia: a subgroup analysis of the TITAN trial

Ethnicity might be associated with treatment outcomes in advanced prostate cancer. This study aimed to evaluate the efficacy and safety of androgen deprivation therapy (ADT) combined with apalutamide in East Asians with metastatic castration-sensitive prostate cancer (mCSPC). The original phase 3 Targeted Investigational Treatment Analysis of Novel Anti-androgen (TITAN) trial was conducted at 260 sites in 23 countries. This subgroup analysis included patients enrolled in 62 participating centers in China, Japan, and Korea. Radiographic progression-free survival (PFS), time to prostate-specific antigen (PSA) progression, and PSA changes from baseline were compared between groups in the East Asian population. The intent-to-treat East Asian population included 111 and 110 participants in the apalutamide and placebo groups, respectively. The 24-month radiographic PFS rates were 76.1% and 52.3% in the apalutamide and placebo groups, respectively (apalutamide vs placebo: hazard ratio [HR] = 0.506; 95% confidence interval [CI], 0.302–0.849; P = 0.009). Median time to PSA progression was more favorable with apalutamide than placebo (HR = 0.210; 95% CI, 0.124–0.357; P < 0.001). Median maximum percentages of PSA decline from baseline were 99.0% and 73.9% in the apalutamide and placebo groups, respectively. The most common adverse event (AE) was rash in the apalutamide group, with a higher rate than that in the placebo group (37.3% vs 9.1%). The most common grade 3 or 4 AEs were rash (12 [10.9%]) and hypertension (12 [10.9%]) for apalutamide. The efficacy and safety of apalutamide in the East Asian subgroup of the TITAN trial are consistent with the global results.