Phase IIIb, Open-label, Multi-center Study to Evaluate Safety, Tolerability and Efficacy of OAV101 Administered Intrathecally to Participants With SMA Who Discontinued Treatment With Nusinersen or Risdiplam

Phase IIIb, Open-label, Single-arm, Multi-center Study to Evaluate the Safety, Tolerability and Efficacy of OAV101 Administered Intrathecally (1.2 x 10^14 Vector Genomes) to Participants 2 to < 18 Years of Age With Spinal Muscular Atrophy (SMA) Who Have Discontinued Treatment With Nusinersen (Spinraza®) or Risdiplam (Evrysdi®)

This was a Phase IIIb open-label, single arm, multi-center study to evaluate the safety, tolerability and efficacy of OAV101B in participants with SMA aged 2 to <18 years after the discontinuation of treatment with nusinersen or risdiplam. The study aimed to enroll approximately 28 participants across each of 2 age brackets (2 to <6 years, and 6 to <18 years).

Eligible participants received a single OAV101B administration of 1.2x1014 vector genomes on Day 1 (Treatment period) and were followed for a period of 52 weeks.

Participants were admitted to the hospital on Day -1 for pre-treatment baseline procedures. After receiving OAV101B on Day 1, participants underwent in-patient safety monitoring over the next 48 hours, after which the participant could be discharged, based on Investigator judgment.

Inclusion Criteria

• SMA diagnosis
• Aged 2 to < 18 years
• Have had at least four loading doses of nusinersen (Spinraza®) or at least 3 months of treatment with risdiplam (Evrysdi®) at Screening
• Must have symptoms of SMA as defined in the protocol

Exclusion Criteria:

• Anti Adeno Associated Virus Serotype 9 (AAV9) antibody titer using an immunoassay is reported as elevated

• Clinically significant abnormalities in test results during screening

• Contraindications for lumbar puncture procedure

• At Baseline, participants are excluded if they received:

  • nusinersen (Spinraza®) or
  • risdiplam (Evrysdi®) within a defined timeframe

• Vaccinations 2 weeks prior to administration of OAV101

• Hospitalization for a pulmonary event, or for nutritional support within 2 months prior to Screening or inpatient major surgery planned.

• Presence of an infection or febrile illness up to 30 days prior to administration of OAV101

• Requiring invasive ventilation