This is an open-label, single arm, multi-center study to evaluate the safety, tolerability and efficacy of IV OAV101 in SMA participants. The study will enroll participants that weigh ≥ 8.5 kg and ≤ 21 kg. An even weight distribution across the desired range will be achieved by aiming to enroll approximately 6-10 participants across 3 weight brackets (≥ 8.5-13 kg, > 13-17 kg, > 17-21 kg). Participants will receive a single administration of IV OAV101.~Participants who meet eligibility criteria at screening and baseline visits will receive a single-dose of IV OAV101 on Day 1 (Treatment period) and will be followed for a period of 12 months. The study will include a standard screening period that can last up to 45 days, during which eligibility will be assessed and baseline assessments will be performed prior to treatment.~For the study duration, participants will complete visits as defined in the Schedule of Assessments. Prednisolone treatment will be given per study protocol. On Day -1, participants will be admitted to the hospital for pre-treatment baseline procedures. On Day 1, participants will receive a 1-time IV infusion of OAV101 and will undergo in-patient safety monitoring over the next 48 hours, after which the participant may be discharged, based on Investigator judgment.~Safety monitoring will be performed as per study schedule and protocol requirement. Safety for the participants enrolled in the study will be evaluated by the study team together with Data Monitoring Committee (DMC) as described in the charter. An interim analysis for safety and efficacy maybe performed once the last participant completes 6-months of follow-up, and will include all available data up until that data cut-off. Final analysis will be planned after the 12 months visits (End of Study (EOS)).~After study completion eligible participants will be invited to enroll into Long Term follow-up study to collect additional safety and efficacy data.
To evaluate the safety, tolerability and efficacy of intravenous administration of OAV101 (AVXS-101) in patients with spinal muscular atrophy (SMA) with bi-allelic mutations in the survival motor neuron 1 (SMN1) gene weighing ≥ 8.5 kg and ≤ 21 kg, over a 12 month period.