The FDA’s approval on March 10 was limited to a genetic disorder that affects fewer than one in a million Americans—a condition that impairs the brain’s ability to receive folate, a form of vitamin B. The agency said the decision does not extend to autism, despite remarks made at a White House news conference in September when President Donald Trump and FDA commissioner Marty Makary suggested the drug might help 20‑50 % of children with the disorder.

Senior FDA officials clarified that the review was “narrowed to focus on the strongest evidence,” which supports use only for patients with the documented cerebral folate deficiency mutation. They also highlighted that a study previously cited to back the autism claim had been retracted earlier this year.

Autism researchers echoed the agency’s caution. Dr. Alycia Halladay of the Autism Science Foundation told reporters there is “no evidence to say that leucovorin will help most people with autism, and there’s certainly no evidence to say it’s safe.” She added that the prevalence of the folate‑related mutation among autistic individuals is unknown, and that the laboratory test used to diagnose it is not FDA‑approved.

Prescription data show the impact of the September announcement. A paper in The Lancet reported a 71 % surge in leucovorin prescriptions for children ages five to 17 during the three months following the conference. Some families have since reported difficulty filling the prescriptions as demand outstripped supply, prompting the FDA to allow imports from foreign manufacturers to bolster availability.

Professional medical societies remain unconvinced. The American Academy of Pediatrics continues to advise against routine leucovorin use for autistic children, and the drug’s current label lists only its role in reducing chemotherapy side effects and treating a rare blood disorder. Health‑care providers are reminded that reported side effects in autistic patients include irritability, aggression and hyperactivity.

The episode illustrates how high‑profile political statements can swiftly shape prescribing patterns, even when the underlying scientific evidence is thin. By retracting earlier claims and emphasizing the drug’s narrow indication, the FDA hopes to steer clinicians and families back toward evidence‑based treatments for autism.