FDA Delays and Rejections Impact Rare Disease and Gene Therapy Development

The FDA has delayed decisions on Regenxbio’s Hunter syndrome gene therapy and rejected PTC Therapeutics’ Friedreich’s ataxia drug vatiquinone, requesting further well-controlled studies. Stealth BioTherapeutics resubmitted its ultra-rare Barth syndrome candidate after a prior rejection and disclosed regulatory challenges. These developments highlight ongoing regulatory complexities affecting rare disease and gene therapy pipelines, influencing clinical timelines and investor confidence.