VP.56a Real-world assessment of onasemnogene abeparvovec treatment in patients with spinal muscular atrophy: RESTORE/post-marketing surveillance in Japan.

Availability of real-world data on spinal muscular atrophy (SMA) has grown, but region-specific data evaluating specific treatments and outcomes within discrete national health systems are limited. We assessed treatment patterns and long-term, real-world outcomes for patients with SMA treated with onasemnogene abeparvovec (OA) in Japan. In line with Japanese regulatory requirements, post-marketing surveillance (PMS) was conducted for patients treated with OA as part of RESTORE, a real-world, prospective, multicenter, multinational, observational registry of patients with SMA. We collected and evaluated data on patients enrolled in RESTORE/PMS who received OA in Japan. This report provides interim results from May 18, 2021 (PMS start) to May 23, 2021 (data cutoff) for 19 patients that had been treated with OA (age range at infusion, 0.0, 24.0 months; weight range at infusion, 2.7, 10.1 kg). Seven patients (36.8%) received OA monotherapy, and 12 (63.2%) received OA after initial nusinersen. Patients had two (n=11/19, 57.9%) or three (n=8/19, 42.1%) copies of the SMN2 gene. Of 5 patients with ≥2 CHOP INTEND assessments, 4 improved (3 achieved a ≥4-point increase), and 1 had a 1-point decrease (change per month range, –0.14, +3.42 points). Of 4 patients with ≥2 motor milestone assessments, 2 achieved new milestones, 1 maintained milestones, and 1 recorded no milestone achievements. No loss of achieved milestones was reported after OA. All patients reported at least 1 treatment-emergent adverse event (AE). Three patients (15.8%) experienced at least 1 serious AE related to OA. Thrombotic microangiopathy and associated events (hemolysis and acute kidney injury) were reported for 1 patient. No deaths were reported. To date, patients in Japan enrolled in RESTORE/PMS achieved or maintained motor milestones after OA. The AE experience of OA for Japanese patients is consistent with the overall safety profile of OA, with no new safety concerns identified. [ABSTRACT FROM AUTHOR]