Cancer drug could double as autism therapy, poised for FDA approval, officials say

A cancer drug already used as a prescription vitamin is moving toward a potential new role in autism treatment, as federal health officials signaled that leucovorin could be approved to address speech-related deficits in children with autism spectrum disorder (ASD). The Food and Drug Administration plans to update the labeling to reflect treatment for cerebral folate deficiency, a condition linked to autism, and state Medicaid programs could begin covering the therapy if the label change proceeds. The NIH will also launch new research initiatives to study leucovorin’s safety and effectiveness in this off-label use.

At a Monday press briefing, FDA Commissioner Marty Makary, NIH Director Jay Bhattacharya, and Centers for Medicare and Medicaid Services Administrator Mehmet Oz described the findings behind the potential use of leucovorin, a long-standing cancer drug and prescription vitamin. Officials stressed that leucovorin is not yet approved to treat autism, but that the agency’s action would formalize a medical option that some families have pursued off-label as part of a broader treatment plan.

What is leucovorin? It is a form of vitamin B9 used to protect healthy cells during high-dose chemotherapy and to prevent or treat certain types of anemia caused by folate deficiency. In autism research and clinical explorations, some studies and clinicians have reported language and communication benefits in a subset of children who receive higher-than-typical doses, alongside behavioral and speech therapies. Proponents note that leucovorin helps restore folate levels in the brain and may address central folate deficiency, which could influence neurological function. Yet experts caution that the evidence base is still evolving and that larger, controlled trials are needed to establish efficacy and safety.

Dr. Richard E. Frye, a behavioral child neurologist in Arizona who has studied leucovorin in autism research, says some children show meaningful improvements in language and communication with the treatment, but results vary and dosing must be carefully supervised. Other clinicians emphasize that while leucovorin appears safe for many years of use in other conditions, high-dose regimens for autism require medical oversight to monitor potential side effects, such as hyperactivity in some children or inadequate response in others. Physicians often tailor formulations, and in some cases a compounded preparation is needed to avoid additives in commercial products that could affect sensitivity.

Experts urge caution despite the optimism. Dr. Frye notes there is no single cure or “magic bullet” for autism, and many children benefit from a combination of therapies, including behavioral interventions and speech therapy. Marc Siegel, a clinician and medical analyst, points out that leucovorin is a potent intervention and should be managed by physicians familiar with its use in autism, particularly given the higher doses involved than typical vitamin regimens. He also notes that a sizable portion of autism cases may involve complex, multifactorial etiologies, so treatments are unlikely to work uniformly for all patients.

While leucovorin has long been available in pharmacies, the debate continues over how to standardize dosing and ensure safety across diverse patient populations. Some families rely on off-label use when conventional therapies yield limited benefits, reporting improvements in communication or social functioning; others experience little to no change or encounter adverse effects. Advocates for broader access say FDA approval would provide stronger medical backing, help establish dosage guidelines, and enable insurance coverage that could broaden access while supporting rigorous monitoring and data collection.

In parallel, the NIH intends to fund and coordinate new studies to assess long-term safety and effectiveness of leucovorin in ASD, with an emphasis on standardized trials that would help determine which subgroups of children might benefit most. FDA officials have stressed that approval for autism-related use would be contingent on robust clinical evidence demonstrating meaningful clinical improvement and manageable risk.

The discussion comes as autism remains a public health priority. CDC estimates indicate that autism affects about 3% of children, underscoring the ongoing need for research into diagnostics, therapies, and supports that can improve communication, social interaction, and overall quality of life for affected individuals and their families. Health officials caution that while leucovorin could become part of a broader treatment strategy, it is not a standalone solution and should be integrated with evidence-based therapies and individualized care plans.

To date, many researchers emphasize the necessity of large, controlled trials to determine how widely applicable any benefits from leucovorin might be. If subsequent studies confirm efficacy and safety, the FDA would weigh formal labeling changes, potential post-approval studies, and considerations for payer coverage. In the meantime, clinicians are advised to consult with families about potential risks, benefits, and the importance of concurrent therapies as part of a comprehensive autism treatment plan.

As the health community weighs the potential of leucovorin to support language development and other ASD-related outcomes, the broader landscape of autism treatment remains diverse and dynamic. The FDA’s forthcoming label update and NIH’s new research initiatives mark a notable step in translating emerging evidence into regulatory and clinical practice, with the goal of expanding access to therapies that could improve functioning for some children while continuing to prioritize safety and individualized care.