Inclusion Criteria:
* Participant has both a clinical diagnosis of Friedreich ataxia (FA) and a documented history of genetic diagnosis of FA with either a guanine-adenine-adenine (GAA) trinucleotide repeat (TNR) expansion in intron 1 of both gene for frataxin (FXN) alleles or a GAA TNR expansion of intron 1 of one FXN allele and a pathogenic variant in the other FXN allele.
* Participant has a resting LVEF ≥ 40% and \< 55% as measured at screening by ECHO.
* Participant has a body mass index range of 17.0 to 30.0 kg/m2.
* Participant agrees not to begin omaveloxolone treatment during the 52-week period after receiving study intervention.
* Participants on omaveloxolone, who opt to discontinue omaveloxolone, may enroll if they stop omaveloxolone for 3 weeks and pass study screening, including LFTs.
* Participants on omaveloxolone, who opt to stay on omaveloxolone will need to have been on it for a minimum of 3 months, with LFTs that pass diagnostic assessments exclusion criteria at screening and prior to dosing with ASP2016. Prior elevation(s) in AST/ALT associated with omaveloxolone use must be discussed with the sponsor medical monitor. If there is a liver function test (LFT) elevation after treatment, participant agrees to stop omaveloxolone treatment until 52 weeks.
* Participants on omaveloxolone will need to discontinue strong or moderate cytochrome P450 3A4 (CYP3A4) inducers and inhibitors.
* Woman of Child Bearing Potential (WOCBP) on omaveloxolone must use a nonhormonal, highly effective methods of contraception (e.g., nonhormonal intrauterine device system), as omaveloxolone may interfere with hormonal methods of contraception.
Exclusion Criteria:
* Participant has late-onset FA, defined as symptom onset after the age of 25 years.
* Participant is unable to complete cardiopulmonary exercise testing (CPET) procedure.
* Participant has a contraindication to endomyocardial biopsy or cardiac catheterization.
* Participant has a contraindication to cardiac magnetic resonance imaging (CMRI) with contrast, including hypersensitivity to gadolinium contrast agent, cardiac pacemaker or implantable cardiac defibrillator.
* Participant has an elevated titer of anti-AAV8 total antibodies, as determined by central testing.
* Participant has significant fibrosis on CMRI, defined as late gadolinium enhancement of \> 15% left ventricular myocardial mass.
View Inclusion and Exclusion Criteria at ClinicalTrials.gov