Adherence and Persistence on Relugolix for the Treatment of Prostate Cancer in the United States Medicare Fee-for-Service Population.

Introduction: This real-world study examined persistence and adherence to oral relugolix in Medicare fee-for-service beneficiaries with prostate cancer (PC).

Methods: In Medicare 100% fee-for-service administrative claims data (2019-2023), eligible patients with PC were identified who had ≥ 2 relugolix claims between December 1, 2020, and September 30, 2023, and 12 months of Parts A, B, and D eligibility before and ≥ 90 days after the first relugolix claim (index date). Persistence (time from first relugolix pharmacy claim to the earliest of either a switch to a different androgen deprivation therapy, discontinuation, death, or end of study period) was assessed up to 36 months after index using a 90-day gap in pharmacy claims to define discontinuation. Adherence, defined as the proportion of patients filling prescriptions to relugolix while persistent on therapy, was assessed every 3 months through month 24 after index using a proportion of days covered ≥ 80% method. Analyses were stratified by PC metastatic status.

Results: Of 5274 patients included, 68% had nonmetastatic PC. Mean (SD) persistence was 11.2 (8.1) months in patients with metastatic PC vs 9.4 (6.9) months in patients with nonmetastatic PC (log-rank test P < .0001). Among patients who persisted on therapy, the adherence rate was 93% through 24 months and was similar between metastatic and nonmetastatic PC cohorts.

Conclusions: Patients who were persistent on relugolix demonstrated high adherence throughout the study, regardless of metastatic status. These results suggest that relugolix has practical utility in real-world clinical practice.