Healthcare resource utilization and costs among patients with metastatic castration-sensitive prostate cancer initiated on apalutamide or enzalutamide in the United States (2019-2023).

[AIMS] This retrospective longitudinal cohort study compared healthcare resource utilization (HRU) and costs among patients with metastatic castration (hormone)-sensitive prostate cancer who initiated apalutamide or enzalutamide, two androgen receptor pathway inhibitors (ARPIs) that have demonstrated efficacy in the treatment of advanced prostate cancer in phase 3 clinical trials.

[METHODS] Linked patient-level data from a practice-related clinical urology database and an administrative claims database in the United States (1 January 2016-31 December 2023) were used. Per-patient-per-month (PPPM) HRU and cost outcomes were compared between the apalutamide and enzalutamide cohorts during the observation period (i.e. from ARPI initiation until continuous insurance eligibility end) after inverse probability treatment weighting to balance differences in baseline characteristics.

[RESULTS] Overall, 486 patients who initiated apalutamide (mean age 70.3 years, 53.5% white, 25.4% Black, 58.1% Medicare-insured) and 601 patients who initiated enzalutamide (mean age 70.5 years, 52.9% white, 25.5% Black, 58.8% Medicare-insured) were included. Duration of continuous treatment use was 9.6 months for apalutamide and 8.6 months for enzalutamide. Despite longer continuous ARPI use among patients treated with apalutamide relative to enzalutamide, the number of inpatient admissions (rate ratio [RR] = 0.58; 95% confidence interval [CI] = 0.37, 0.86;  = 0.012), number of admission days (RR = 0.58; 95% CI = 0.19, 0.70;  = 0.004), as well as all-cause medical costs (mean monthly cost difference = -$1,845; 95% CI = -$52, -$4,908;  = 0.044) were significantly lower in the apalutamide cohort than the enzalutamide cohort during the observation period. Mean monthly all-cause pharmacy costs between the cohorts was not significantly different ($2,121; 95% CI = -2,389, 5,703;  = 0.320).

[LIMITATIONS] This study relied on administrative claims and clinical data, which may contain coding inaccuracies or omissions. While linkages between the data sources are comprehensive, any mislinkages may have led to misclassification and information bias.

[CONCLUSION] The findings of this study suggest that apalutamide may result in better economic outcomes relative to enzalutamide.