In 2019, FDA granted accelerated approval to voxelotor for sickle cell disease based on a surrogate endpoint: hemoglobin increase. The mechanism was sound. Voxelotor increased hemoglobin oxygen affinity, which should reduce sickling and improve outcomes. The biology made sense. The FDA agreed. Patients got access. In September 2024, the drug
In September 2016, the FDA approved eteplirsen for Duchenne muscular dystrophy. The advisory committee had voted 7 to 6 against accelerated approval. The FDA's own review team recommended against it. The clinical program consisted of 12 boys, and western blot analysis showed a dystrophin increase of 0.93%
Between late 2024 and late 2025, FDA approved six rare-disease therapies supported primarily by single-arm trials. None of these sponsors ran randomized controlled trials. All received traditional or accelerated approval. What separated success from rejection wasn’t luck or regulatory leniency. It was understanding what evidence compensates for the absence
