The purpose of this study was to determine the impact of expanding belzutifan access to VSP on time to first fill from treatment decision, number of gaps in therapy after initiation, and adherence. Patients who filled once VSP gained access to dispense belzutifan, initiated treatment more quickly, had fewer treatment gaps, and improved adherence compared to those who began treatment before VSP gained access to belzutifan. These findings support prior studies showing HSSPs outperform non-HSSPs