Objective: We sought to describe health care resource utilization (HCRU) for patients with spinal muscular atrophy (SMA) in the United States.
Background: Limited real-world evidence exists for HCRU following treatment of SMA with disease-modifying therapies (DMTs).
Methods: 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 SMA-related HCRU (inpatient [IP] admissions, emergency room [ER] visits, consultation visits) were collected. The index date was the date of monotherapy initiation or the switch to OA. The baseline period was the time from onset of SMA symptoms or SMA diagnosis (whichever was earlier) until index. The follow-up period was the time from index until the end of data availability. HCRU was summarized per patient-year (PPY).
Results: This interim analysis included 31 patients: 10 nusinersen monotherapy; 11 OA monotherapy; 10 switchers. SMA types at diagnosis were type 1 (5/10; 3/11; 8/10), type 2 (4/10; 5/11; 1/10), type 3 (1/10; 3/11; 0/10), and undetermined (0/10; 0/11; 1/10), respectively. Mean ages at index (±standard deviation) were 38.4±14.5, 16.3±5.8, and 17.9±7.8 months. 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 1.03 vs. 0.28, 0.41 vs. 0.00, and 1.64 vs. 0.41 PPY; rates of ER visits were 1.50 vs. 0.64, 0.14 vs. 0.71, and 1.64 vs. 0.21 PPY; rates of SMA-related consultation visits were 3.21 vs. 8.50, 5.00 vs. 6.96, and 9.03 vs. 8.59 PPY.
Conclusions: Patients experienced reductions in the rate of IP admissions following DMT, with no admissions reported after receiving OA monotherapy. Rates of ER visits post-treatment were comparable between nusinersen monotherapy and OA monotherapy patients, and lower among those switching to OA.