OBJECTIVES: In the United States, real-world evidence on apalutamide (APA) for treatment of patients with metastatic castration-sensitive prostate cancer (mCSPC) is limited. This study describes prostate-specific antigen (PSA) response and treatment persistence among patients with mCSPC initiated on APA, with stratifications for Black/non-Black patients.

METHODS: Clinical data from 77 community-based urology practices were used to evaluate patients with mCSPC who received ≥1 APA dispensation (index date = first dispensation). Patients who previously used another next-generation antiandrogen or had <12 months of pre-index clinical activity were excluded. Patients were followed from index date to end of clinical activity or data availability (4/1/2022). On-treatment PSA response (≥90% decline from baseline PSA [PSA90]) 12-months post-index was assessed among patients with reported baseline PSA <13 weeks prior to or on the index date. Persistence was defined as the percentage of patients with no gap in treatment >60 or >90 days of supply at 6- and 12-months post-index. Outcomes were described overall and stratified for Black/non-Black patients.

RESULTS: Overall, 589 patients with mCSPC initiated APA (mean age 75.9 years; 98 Black [16.6%], 424 non-Black [72.0%], and 67 of unknown race [11.4%]). By 12-months, PSA90 response was achieved by 72.3% overall, and 73.1% and 70.8% for Black and non-Black patients, respectively. Persistence at 6 months using >60- and >90-day gaps were 92.7% and 96.8% overall, 95.4% and 98.5% for Black patients, and 93.4% and 96.9% for non-Black patients, respectively. Persistence at 12 months using >60- and >90-day gaps were 89.1% and 94.9% overall, 93.3% and 97.8% for Black patients, and 89.3% and 94.4% for non-Black patients, respectively.

CONCLUSIONS: Patients with mCSPC initiated on APA exhibited high real-world PSA response rates, and few patients had gaps in therapy. Robust real-world PSA response rates and treatment persistence were also demonstrated for both Black and non-Black patients.