Abstract
INTRODUCTION: Spinal muscular atrophy (SMA) is a neurogenic disorder associated with progressive loss of muscle function, respiratory failure, and premature mortality. This study aimed to describe and compare real-world health care resource utilization (HCRU) and costs for US patients with SMA treated with disease-modifying treatments, including onasemnogene abeparvovec, nusinersen, and/or risdiplam. METHODS: This study used claims and structured electronic medical record data from the HealthVerity claims database (January 1, 2017-March 31, 2021). Eligible patients were aged ≤ 2 years at index (treatment initiation or switch), diagnosed with SMA, had ≥ 1 pharmacy/medical claim for onasemnogene abeparvovec, nusinersen, and/or risdiplam, and continuous enrollment ≥ 1 month pre- and ≥ 2 months post-index. SMA-related HCRU and costs during the study period (> 12 months post-index) were compared between treatment groups before and after propensity score weighting. Costs were adjusted to 2021 USD. RESULTS: Of 74 included patients, 62 (83.8%) received nusinersen and 12 (16.2%) received onasemnogene abeparvovec (monotherapy, n = 9; onasemnogene abeparvovec after nusinersen [switching], n = 3). After weighting, nusinersen-treated patients had greater annual numbers of inpatient (mean 5.3 nusinersen vs. 1.8 onasemnogene abeparvovec) and emergency department (mean 3.0 nusinersen vs. 1.5 onasemnogene abeparvovec; p < 0.05) visits, and greater annual SMA-related medical costs (mean $78,446 nusinersen vs. $29,438 onasemnogene abeparvovec; mean difference $49,007, p < 0.05) than onasemnogene abeparvovec-treated patients. Onasemnogene abeparvovec-treated patients incurred greater SMA-treatment pharmacy costs than nusinersen-treated patients (mean $2,241,875 onasemnogene abeparvovec vs. $693,191 nusinersen; mean difference $1,548,684, p < 0.05). CONCLUSIONS: SMA is associated with substantial economic burden. Patients treated with onasemnogene abeparvovec had greater SMA treatment-related pharmacy costs but lower SMA-related HCRU and medical costs compared with patients receiving nusinersen monotherapy.