ACMT warns against premature leucovorin use for autism

The American College of Medical Toxicology says leucovorin should not be used for autism spectrum disorder outside clinical research, citing limited evidence behind the FDA’s new indication and potential risks to cancer care supply. The group is urging continued research while warning that standard FDA approval and labeling processes should not be bypassed.

Why it matters: - The American College of Medical Toxicology is cautioning that broader leucovorin use for autism spectrum disorder could raise costs and strain access for patients who need the drug for cancer treatment, methotrexate toxicity and certain vitamin deficiencies. - The statement also warns that families affected by autism have been targeted by pseudoscientific treatments before, and some of those therapies have caused harm. - ACMT says leucovorin should be used for autism spectrum disorder only in clinical research until stronger data exist.

What happened: - ACMT issued a position statement on July 8, 2026, from Phoenix, Arizona, on the use of leucovorin for autism spectrum disorder. - The group said the FDA approved leucovorin for a rare, specific form of cerebral folate deficiency that overlaps with autism spectrum disorder, but the approval was based on case reports and a mechanistic rationale rather than clinical trials. - ACMT said the FDA’s usual evidentiary standard for approval was bypassed in this case.

The details: - ACMT supports continued research into folate metabolism in autism spectrum disorder and new treatments for the condition. - The organization says the FDA’s robust framework for drug approval and labeling changes should not be bypassed. - ACMT, along with the American Academy of Pediatrics, says it stands firmly against premature use of leucovorin for autism spectrum disorder. - The full position statement is available here.

Between the lines: - ACMT is drawing a clear line between research interest in folate pathways and real-world prescribing before the evidence base is settled. - The warning reflects concern that a narrow FDA indication could spill into much broader off-label use for a far more common diagnosis.

What's next: - ACMT wants further clinical research before leucovorin is adopted more widely for autism spectrum disorder. - The organization is pressing for labeling changes, if any, to move through the standard FDA process rather than shortcutting evidence requirements.