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 ≤ 24 months that weigh ≤ 17 kg. Participants will receive a single administration of IV OAV101 at the approved dose of 1.1e14 vg/kg.~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 18 months. The study will include a standard screening period that can last up to 20 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 (SoA). 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 18 month visit end of study (EOS).~After study completion eligible participants will be invited to enroll into a Registry study (RESTORE) 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 SMA with bi-allelic mutations in the survival motor neuron 1 (SMN1) gene ≤ 24 months and weighing ≤ 17 kg, over a 18-month period post infusion.