Association of race and survival in patients treated with apalutamide: Pooled analysis of two phase 3 trials

BACKGROUND: Clinical studies have shown that outcomes of patients with prostate cancer could vary depending on race. In this study, the authors sought to determine if the treatment effect of apalutamide, an androgen receptor pathway inhibitor (ARPI), on overall survival (OS) varies depending on the race of the patient. METHODS: This pooled analysis includes individual patient data from two phase 3 trials, TITAN and SPARTAN, which randomized patients to androgen deprivation therapy (ADT) ± apalutamide in metastatic hormone-sensitive and nonmetastatic castration-resistant prostate cancer, respectively. Race was self-identified and categorized as Asian, Black, White, and Others categories. The authors applied a stratified (stratification for the trial) multivariable Cox proportional hazards regression model to determine heterogeneity of treatment effect on OS after adjustment for age, performance status, body mass index, T- and N-stage, Gleason score, comorbidities, and exposure to statins and metformin. RESULTS: Overall, 2190 patients were included: 16.9% patients were Asian, 3.7% were Black, 67.4% were White, and 12.0% were from the Others category. The authors did not find any significant heterogeneity of treatment effect from apalutamide on OS across racial groups (interaction-p = .46). Among ADT plus apalutamide-treated patients, there was no association of race with OS (hazard ratio for Asian, 0.77 95% CI, 0.56-1.06; Black, 0.82 95% CI, 0.49-1.37; and Others, 1.00 95% CI, 0.75-1.34, all compared to White). CONCLUSIONS: In this study, the authors did not find any evidence of difference in the treatment effect of apalutamide on OS across patients of different races, although interpretation remains limited by poor representation of racial minorities. Among apalutamide-treated patients, there was no association of race with OS.