FDA Plans for Expedited Licensure Approval of GSK’s Autism Drug

On Sept. 22, 2025, the U.S. Food and Drug Administration (FDA), in collaboration with the British pharmaceutical company GSK plc, announced plans to fast-track licensure of leucovorin calcium tablets. The drug, which GSK calls Wellcovorin, has long been used to treat anemia and counteract the effects of chemotherapy, The FDA will approve it for use in treating autism-related symptoms in children with cerebral folate deficiency (CFD), a neurodevelopmental disorder that has both genetic and environmental exposure risk factors, and can cause symptoms that are similar to those experienced by children diagnosed with autism spectrum disorder (ASD), such as repetitive behaviors, seizures, and problems with sensory processing, movement, coordination and social communication.^{1 2}

“The FDA is collaborating with GSK to broaden the existing Wellcovorin label,” said George Tidmarsh, MD, PhD, director of the FDA’s Center for Drug Evaluation and Research in a statement. “This effort reflects the FDA’s commitment to identify opportunities to repurpose drugs to treat chronic diseases. The FDA remains committed to finding and treating the root causes of autism.”¹

The FDA expedited the licensing process by invoking a rarely used regulatory provision to reinstate GSK’s original approval application and request a label update adding cerebral folate deficiency (CFD), based on its own review of 40 patient cases published between 2009 and 2024. The goal is to expand the drug’s indication to include CFD in children with autism, though leucovorin calcium remains approved only for CFD, not autism itself. Some clinical trials and case studies have reported improvements in communication, cognition, and social engagement in autistic children who test positive for CFD and receive the drug.³

The FDA’s statement notes:

Individuals with cerebral folate deficiency have been observed to have developmental delays with autistic features (e.g., challenges with social communication, sensory processing, and repetitive behaviors), seizures, and problems with movement and coordination.⁴

FDA’s Timeline Expands Access to Autism Symptom Treatment

By fast-tracking the drug’s approval for treatment of CFD, the FDA can shorten the review process for licensure from several years to as little as six months, allowing GSK to submit existing safety and efficacy data while ongoing clinical trials continue. For GSK, the designation offers a financial incentive as well: a new indication, even for an existing drug, can generate market exclusivity and insurance coverage eligibility. Without it, the company would likely face 8–12 years of additional clinical studies and regulatory review before the drug could be officially marketed for CFD in children with autism. A GSK spokesperson told Reuters it plans to complete the new use application for the branded version of leucovorin “as quickly as possible.”²

Critics have questioned what they describe as an “unusual move” by the FDA to accelerate the licensing process. Ameet Sarpatwari, PhD, JD, a pharmaceutical policy researcher at Harvard Medical School, said that without robust evidence, the label change represents “at most, a hollow bureaucratic victory.” Dr. Andy Shih, chief science officer at Autism Speaks, said the evidence for leucovorin’s effectiveness remains preliminary and may apply only to a small subset of autistic children, adding that larger studies are needed to validate the findings.²

The FDA’s decision has drawn more skepticism than similar expedited approvals, such as during the COVID-19 pandemic, when the agency fast-tracked emergency use authorization for experimental mRNA biologics developed under Operation Warp Speed, which had no long-term safety data at the time of rollout. A U.S. Department of Health and Human Services (DHHS) spokesperson said the evidence “clearly supports leucovorin’s ability to address the causes of cerebral folate deficiency and improve patient outcomes.”²

Drug Demand Surges After White House Press Conference and Reports of Successful Treatment of Autistic Children

In September at a White House press conference with DHHS Secretary Robert Kennedy, Jr, President Donald Trump mentioned that there was an “existing drug” that is being used to treat autism symptoms.  While the drug is not new and further research is needed, some providers were already prescribing it off-label to support families struggling with symptoms of autism. One of those providers is Richard Frye, MD, a behavioral child neurologist in Phoenix who has studied leucovorin and autism for more than two decades. One of his pediatric patients, Benjamin Noonan, has seen significant improvements since starting the medication. “He’s higher functioning,” Benjamin’s father, Brian Noonan, said. “He’s verbal, but he really struggled to put together sentences.” Since beginning leucovorin, Benjamin’s speech has improved, though his father says he still experiences hyperactivity and impulsiveness. ⁵

Another family reported “major improvement” in their 11-year-old son, Josh, who they described as having “pretty severe” autism. “He didn’t have any language skills. He was not toilet-trained,” said Ben Blomgren, the child’s father. Since starting the medication, Josh now sleeps better, is fully toilet-trained, and no longer runs away from his parents.⁵

Yomarie Miranda also noticed measurable progress in her seven-year-old son, Ethan, including following instructions in class and making eye contact when speaking. “He’s talking more than before, with complete sentences,” she said.⁵

Reuters reported that the demand for leucovorin sharply increased since the White House announcement, with one doctor’s office reporting that the “phone is ringing off the hook,” according to Larry Gray, MD, an expert in developmental and behavioral pediatrics at Lurie Children’s Hospital of Chicago.²

Plans to Overhaul Federal Vaccine Injury Compensation Program

DHHS Secretary Kennedy recently announced plans to overhaul the National Vaccine Injury Compensation Program (VICP). As part of the proposed updates, he said the agency is considering adding specific autism-related symptoms to the official list of vaccine side effects eligible for federal compensation. The sweeping changes come nearly two decades after the Omnibus Autism Proceeding, when thousands of autism claims were consolidated into one class action type proceeding and a series of hearings were held by special masters appointed by the U.S. Court of Federal Claims, who concluded that the scientific evidence did not support a causal link between vaccines and autism. This ruling by Court of Federal Claims special masters, who were not medical doctors or experts on vaccines or autism, essentially closed the door on future claims.⁶

“We have witnessed a tragic four-fold increase in autism over two decades,” said FDA commissioner Marty Makary, MD, MPH in the FDA’s Sept. 22 statement. “Children are suffering and deserve access to potential treatments that have shown promise. We are using gold standard science and common sense to deliver for the American people.”¹

Three ongoing clinical trials are testing a liquid formulation of leucovorin as a potential treatment for early language impairment in children with autism. The studies, each involving up to 80 participants, are being conducted by an autism researcher in collaboration with the National Institutes of Health (NIH), the Department of Defense (DoD), and Autism Speaks, according to the government clinical trials site. ⁷ FDA officials said:

In the coming weeks, the FDA will approve leucovorin as a treatment for children with cerebral folate deficiency and autistic symptoms. Over half of all American children are insured by Medicaid or CHIP, so upon this FDA label change, states will be required to cover leucovorin around the country.⁸

If you would like to receive an e-mail notice of the most recent articles published in The Vaccine Reaction each week, click here.