OBJECTIVES: Data on disease-modifying therapy (DMT) use for patients with spinal muscular atrophy type 2 (SMA2) are limited. We sought to describe real-world outcomes and health care resource utilization (HCRU) for patients in the United States with SMA2 aged ≥6 months at time of treatment with onasemnogene abeparvovec (OA) monotherapy or nusinersen switching to OA.

METHODS: We conducted a retrospective chart review. The index date was date of OA initiation. Patient characteristics and outcomes were summarized descriptively for patients with available data at or before the index date and with ≥1 follow-up visit. HCRU (inpatient admissions, emergency room [ER] visits, and consultation visits) was summarized per patient-year (PPY).

RESULTS: Ten patients (nine on OA monotherapy and one on nusinersen who switched to OA [“switcher”]) were included. On the index date, 6/9 and 1/1 patients weighed ≥8.5 kg, and mean ages (±SD) were 13.0±4.8 and 22.0±0 months, respectively. Improvement and/or maintenance of motor milestones (including sitting, standing, and walking) was achieved by 8/8 and 1/1 patients, respectively. Mean time to initial improvement in any motor milestone (±SE) was 1.9±0.5 months for OA monotherapy. The switcher maintained previously achieved motor function improvements. For patients treated with OA monotherapy and the switcher, 8/9 and 1/1 improved/maintained normal cry function; 7/7 and 1/1 improved/maintained speech function; and 7/7 and 1/1 improved/maintained any eating function, respectively. Rates of inpatient admissions at baseline vs. follow-up were 0.26 vs. 0 and 0 vs. 0 PPY; ER visits, 0.26 vs. 0.42 and 0 vs. 0 PPY; and SMA-related consultations, 3.15 vs. 3.97 and 3.24 vs. 0 PPY, respectively.

CONCLUSIONS: Patients with SMA2 improved/maintained function across multiple outcomes after receiving OA, with rapid onset of therapeutic effect. Patients also experienced reductions in the rate of inpatient admissions, with no admissions reported after receiving OA as monotherapy or after nusinersen.