For months, parents of children with autism held onto something that felt rare in this space: a specific name, a specific drug, and what sounded like a specific promise. It came from the White House. It came with cameras rolling. And for a brief window, it felt like something might finally be changing for their kids. Then Tuesday arrived.
The Food and Drug Administration approved a new use for leucovorin, a synthetic form of vitamin B9 most commonly used to reduce the side effects of chemotherapy. The approval, however, covers cerebral folate deficiency tied to a confirmed variant in the folate receptor 1 gene, an ultra-rare neurological condition estimated to affect roughly 1 in 1 million people. Fewer than 50 cases have ever been documented worldwide. It was not the announcement many families had been waiting for.
What the White House said last fall
In September 2025, President Donald Trump stood alongside FDA Commissioner Dr. Marty Makary and Health and Human Services Secretary Robert F. Kennedy Jr. at a White House briefing and described leucovorin as a therapy that could benefit large numbers of children with autism. Makary said that hundreds of thousands of kids would benefit, pointing to data suggesting the drug improved speech in roughly 60% of children with autism and folate deficiency. Trump said the updated drug label would give hope to parents of autistic children by reflecting its potential to improve their lives.
In the weeks that followed, leucovorin prescriptions for children rose 71%, according to data published in the medical journal The Lancet. Parents reported difficulty finding providers and pharmacies willing or able to fill the drug. Some turned to unregulated over-the-counter folate supplements when the prescription version was unavailable.
What the FDA actually found
Senior FDA officials said Monday that the evidence simply did not support a broader autism approval. The largest randomized, double-blind, placebo-controlled trial examining the drug in children with autism was recently retracted after researchers identified errors in the reported data. Without that study, the remaining body of evidence was too thin to meet the agency’s standard for establishing efficacy.
The approval that did move forward was based on a systematic review of published case reports and mechanistic data rather than the traditional randomized controlled trials the FDA typically requires. Officials said that given how rarely the genetic condition occurs, running a placebo-controlled trial would present ethical problems, particularly because children with the gene defect showed dramatic responses to the treatment in existing case studies, including some becoming seizure-free entirely.
The condition covered by Tuesday’s approval affects folate transport into the brain and nervous system, producing low folate levels in the brain despite normal levels in the blood. Children with the defect can experience seizures, developmental delays and symptoms that resemble autism spectrum disorder. That surface-level overlap is what researchers say led to some of the confusion, but experts are clear that the two conditions do not share the same underlying cause.
What families are left with
Researchers who spoke to reporters following the announcement expressed concern about the mixed messaging families have absorbed over the past six months. A psychiatry professor at the University of Pennsylvania described the back-and-forth as harmful, noting that families navigating autism deserve careful science and accurate information rather than announcements that later require walking back.
Doctors can still prescribe leucovorin off-label for autism, as some were already doing before the September briefing. The FDA said it does not run clinical trials and is not currently funding large-scale studies on the drug for autism, though other federal research efforts may be underway.
For families who spent months searching for the drug, navigating pharmacies and holding onto hope that something concrete had finally arrived, the distance between what was said in September and what was approved on Tuesday is not a small one.
The FDA called Tuesday’s decision a significant milestone. Whether the families who were told to expect more would use the same words is a different question entirely.