Assessing Impact of Health System Specialty Pharmacy Support on Initiation of Vigabatrin Therapy for Infantile Epileptic Spasms Syndrome

Abstract Purpose Infantile epileptic spasms syndrome (IESS) is a severe form of pediatric epilepsy requiring urgent diagnosis and treatment. Vigabatrin is a standard therapy but often requires inpatient initiation because of delays in outpatient access due to prior authorization (PA) requirements and distribution restrictions. The primary objective was to determine if a proactive vigabatrin PA workflow through health system specialty pharmacy (HSSP) reduced hospital admission for treatment initiation. This study also explored the time from vigabatrin initiation to PA approval and the number of patients starting vigabatrin within 14 days of prior treatment. Methods This retrospective, single-center study evaluated patients aged one month to two years with new-onset IESS and treated with vigabatrin. Patients treated between May 1, 2019, and December 31, 2024, were compared with those treated between March 1, 2025, and December 31, 2025. Demographic, clinical, and medication access data were analyzed using descriptive and comparative statistics. Results Each cohort contained 19 patients with similar baseline characteristics. Hospital admissions for vigabatrin initiation decreased from 57.9% to 5.3% (p < 0.001). In the pre-intervention cohort, PA approval occurred on the day of vigabatrin initiation, whereas in the post-intervention cohort approval occurred a median of 5 days before initiation (p = 0.04). The number of patients starting vigabatrin within 14 days of first treatment was similar between cohorts (12 and 13 respectively, p = 0.73). Conclusions Implementation of a HSSP-driven proactive PA workflow significantly reduced hospital admissions for vigabatrin initiation and permitted earlier PA approval supporting HSSP integration for time-sensitive therapies.