Neuromuscular Disorders 31 (2021) S47-S162 treatment was ongoing in 7/13 patients. As of November 12, 2020, 31 patients (IV cohort, n = 23; IT cohort, n = 8) were enrolled in LT-002. One patient in each cohort reported SAEs, and one AESI was reported in the IV cohort (treatment-unrelated). None required permanent ventilation and 9 patients reported baseline respiratory support. Among patients for whom motor milestone data are available from baseline visits as of the data cutoff, 11 new milestones that were not achieved in the parent study were achieved for 4 patients, all in the IV cohort. The highest new milestone achieved in the 4 IV cohort patients was sitting without support. Enrollment is ongoing in LT-002. A single IV administration of onasemnogene abeparvovec at the therapeutic dose provided a sustained, durable response for up to 5.6 years since dosing for patients up to 6.1 years of age. There have been no reported treatment-related SAEs or AESIs, supporting a favorable benefit-risk profile.