GlaxoSmithKline filed for a new FDA label for leucovorin, asking regulators to approve the drug for a developmental disability the company says is linked to autism spectrum disorder. GSK confirmed the submission and said it provided clinical and mechanistic data to support the indication. The application will require the agency to review evidence for efficacy and safety in a pediatric neurodevelopmental population; leucovorin is an established folinic acid used in oncology and other settings, but this proposed indication is novel and could trigger close scrutiny over trial design, endpoints and long‑term follow‑up. The company noted ongoing engagement with clinicians and patient groups as part of its regulatory strategy.