SMA – OUTCOME MEASURES AND REGISTRIES: EP.258 Health care resource utilization in pediatric patients with spinal muscular atrophy: Interim analysis of a US retrospective chart review study

Abstract

Patients with spinal muscular atrophy (SMA) have greater health care resource utilization (HCRU) because of progressive muscle weakness, atrophy, and associated complications. No prior studies have assessed HCRU following the initiation of disease-modifying therapies (DMTs). We conducted a retrospective chart review in the United States for SMA patients aged ≥6 months treated with nusinersen monotherapy, onasemnogene abeparvovec (OA) monotherapy, or nusinersen switching to OA. Patient characteristics and outcomes, including major SMA-related HCRU (inpatient [IP] admissions, emergency room [ER] visits, consultation visits) were collected. The index date was the date of monotherapy initiation or switch to OA. The baseline period was the time from the onset of SMA symptoms or time of SMA diagnosis (whichever came earlier) until index. The follow-up period was the time from the index date until the end of data availability. HCRU was summarized per patient-year (PPY). This interim analysis of 20 patients included 8 who received nusinersen monotherapy, 4 who received OA monotherapy, and 8 who switched to OA from initial nusinersen. SMA type at diagnosis was type 1 (4/8; 1/4; 6/8), type 2 (3/8; 1/4; 1/8), type 3 (1/8; 2/4; 0/8), and undetermined (0/8; 0/4; 1/8), respectively. Mean age at index (±standard deviation) was 39.9±12.7, 17.3±7.8, and 18.3±8.6 months, respectively. Among patients treated with nusinersen monotherapy, OA monotherapy, and nusinersen switching to OA, rates of IP admissions in the baseline vs. follow-up period were 1.21 vs. 0.28, 0.52 vs. 0.00, and 1.32 vs. 0.12 PPY; rates of ER visits were 1.69 vs. 0.62, 0.00 vs. 0.00, and 1.73 vs. 0.12 PPY; and rates of SMA-related consultation visits were 3.64 vs. 6.93, 4.95 vs. 3.79, and 7.83 vs. 4.14 PPY, respectively. Patients treated with OA monotherapy or nusinersen switching to OA had lower SMA-related major HCRU following treatment compared with patients treated with nusinersen monotherapy.