Background: Real-world data describing treatment patterns and outcomes for patients with SMA type 2 (SMA2) are limited. Patients with untreated SMA2 typically have clinically identifiable disease symptoms between 6–18 months of age, and are able to sit independently, but are unable to walk without support.
Objective: We sought to describe real-world treatment patterns and outcomes for patients with SMA2 receiving onasemnogene abeparvovec (OA) monotherapy or who switched to OA from nusinersen.
Methods: RESTORE is an ongoing SMA patient registry that captures patient data from a variety of sources. We analyzed changes in motor milestones and motor function scores and assessed treatment-emergent adverse events (TEAEs) for patients who received OA monotherapy or switched to OA from nusinersen.
Results: As of Nov. 23, 2021, 34 patients with SMA2 were identified. Six (17.7%), 27 (79.4%), and 1 (2.9%) had two, three, or four SMN2 gene copies, respectively. Median age at SMA diagnosis was 13.0 months. Age at first DMT administration was 14.0 months. Median interval between diagnosis and first DMT was 1 month. Two-thirds (n=23/34) of patients received OA monotherapy; 11 patients switched to OA from nusinersen. Of 23 patients with ≥2 motor milestone assessments (≥1 post-DMT administration), all but three (OA only [n=3]) maintained or achieved new milestones: 14 (60.9%) received OA monotherapy and six (26.1%) switched to OA from nusinersen. Ten of 11 (90.9%) patients evaluable for CHOP INTEND improved/maintained score, with eight (72.7%) achieving a ≥4-point increase. Any-stage TEAEs were recorded for 11/23 (47.8%) patients who received OA monotherapy and 7/11 (63.6%) who switched to OA from nusinersen. AEs in RESTORE are consistent with overall OA experience. No new safety signals were identified.
Conclusions: Real-world data from RESTORE indicate that OA is effective and has an acceptable safety profile for patients with SMA2, regardless of prior treatment with nusinersen.