Comparison of deep prostate-specific antigen response in Black patients with metastatic castration-sensitive prostate cancer initiated on apalutamide or enzalutamide

<b>Aim:</b> There is limited real-world evidence about prostate-specific antigen (PSA) response to androgen receptor pathway inhibitor treatment in Black patients with metastatic castration-sensitive prostate cancer (mCSPC). This study compared PSA90 (≥90% reduction from baseline PSA level) between apalutamide and enzalutamide among Black patients with mCSPC. <b>Materials & methods:</b> Electronic medical record data (Precision Point Specialty Analytics) were linked to claims data (Komodo Research Database) and used to select cohorts of Black patients with mCSPC treated with either apalutamide or enzalutamide. Inverse probability of treatment weighting was used to balance treatment cohorts. PSA90 response was assessed using weighted Kaplan-Meier curves and hazard ratios with 95% CIs. <b>Results:</b> The study included 451 patients (apalutamide: 230, enzalutamide: 221) with balanced baseline characteristics after inverse probability of treatment weighting. Patients treated with apalutamide had a 42% higher rate of PSA90 response within 6 months post-index compared with those treated with enzalutamide (hazard ratio: 1.42, 95% CI: 1.06, 1.91; p = 0.020). Median time to first PSA90 response was shorter among patients treated with apalutamide (3.3 months) compared with enzalutamide (5.5 months). <b>Conclusion:</b> In Black patients with mCSPC, apalutamide led to faster and significantly deeper PSA responses than enzalutamide, suggesting potential clinical advantages in optimizing early treatment response in this population. Future research should assess PSA90 as a prognostic indicator of overall survival among Black patients.