Study of NBIB-223 Gene Therapy in Friedreich's Ataxia (FACET)

Key Inclusion Criteria:

• Has both a clinical and genetic diagnosis of Friedreich's Ataxia, with diagnosis occurring at least 1 year prior to Screening and when the participant was age ≤16 years.

  • Documented prior genetic diagnosis of Friedreich's Ataxia with a pathogenic GAA trinucleotide repeat expansion in intron 1 of both frataxin alleles, based on analysis by a Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory.
  • Clinical evidence of symptomatic neurologic disease consistent with Friedreich's Ataxia.
  • Have an Modified Friedreich Ataxia Rating Scale (mFARS) overall score ≥15 and <80, and an Modified Friedreich Ataxia Rating Scale subscale E: Upright Stability (mFARS-E) gait score of ≥1.

• Participants who are currently taking omaveloxolone must have initiated treatment at least 1 year prior to Screening and have been on a stable dose for at least 12 weeks prior to Screening, with no anticipated dose adjustments during the 48-week period following NBIB-223 infusion.

• Participants who are not currently taking omaveloxolone must agree not to start taking omaveloxolone during the 48-week period following NBIB-223 infusion.

Key Exclusion Criteria:

• Pregnant, plan to become pregnant during the first 12 months of the study, or lactating.
• Have protocol-specified laboratory abnormalities at screening.
• Previous exposure to adeno-associated virus (AAV)-9 as determined by the presence of serum total anti-AAV9 antibodies (TAb).
• Contraindication to cerebrospinal fluid collection via lumbar puncture, magnetic resonance imaging with contrast, or endomyocardial biopsy.
• Have had a myocardial infarction, cerebrovascular accident, thromboembolic event, or transient ischemic attacks, or have evidence of myocardial ischemia and/or clinically significant cardiac valve disease, obstructive cardiac disease, or arrhythmias.
• Have an ongoing medical condition that, in the opinion of the investigator, would compromise the participant's safety or successful participation in the study or interpretation of study results.
• Have uncontrolled diabetes (hemoglobin [Hb] A1c >8.0%)
• Have an active fungal, bacterial, or viral infection.
• Have scheduled or planning to schedule surgical treatment for scoliosis, foot deformity, or other indications during the first 18 months of the study that will interfere with the participant's ability to complete study assessments.
• Any history of participation in a cellular or gene therapy clinical study, or any history of having been treated with a cellular or gene therapy.
• Have participated in any other interventional clinical study within 30 days prior to Study Day 1 or receipt of any investigational product within the 30 days of enrollment or 5 half-lives of the investigational product, whichever is longer.

Additional inclusion/exclusion criteria may apply, per protocol.