The Food and Drug Administration on Tuesday approved a decades-old prescription vitamin called leucovorin as the first treatment for a rare genetic disorder in some adults and children.
The move comes months after the Trump administration touted leucovorin as a potential treatment for a broader group of patients with symptoms of autism spectrum disorder. This claim sparked skepticism from some in the medical and research community, but fueled enthusiasm among families, increasing prescriptions of the drug in the United States.
An FDA official told reporters Monday that “we don’t have enough data to say that we could establish broader effectiveness for autism” but said the agency was open to corporate interest in studying leucovorin in the autism population.
The drug, also called folinic acid, is a synthetic form of vitamin B9 used to treat the toxic side effects of chemotherapy. Only a handful of small trials have suggested that leucovorin might be effective as an off-label treatment for children with autism, and some families have reported that it helped their nonverbal children develop more language and social skills.
FDA officials, who requested anonymity to discuss the decision, told reporters Monday that they began with a broad review of leucovorin as a treatment for autism before narrowing its approval to a smaller population with brain folate deficiency, a rare genetic mutation that prevents folate — a key vitamin — from properly reaching the brain.
This condition shares common features with autism, typically develops in young children under 2 years of age, and can lead to severe developmental delays, seizures, lack of muscle control, and other serious neurological complications.
Officials said the FDA found that the use of leucovorin in patients with the disease produced “the highest quality data” to support expanded approval, which would apply to both generic versions of the drug and GSK’s former brand, Wellcovorin.
“These are the data where we saw the largest effects,” an FDA official said on the call. “So we focused on that population, just because we felt that was both the strongest scientific rationale and also the strongest therapeutic effect that could be used to then overcome some of the limitations of the data sources.”
Approval was based on a systematic review of published literature in the field, including patient case reports, but not on a randomized controlled clinical trial. The same official acknowledged that there could be bias in systematic reviews, but stressed that the treatment effects were so large that they outweighed these concerns.
The FDA is encouraging existing leucovorin manufacturers to increase production to meet increased demand for the drug, officials added. While GSK initially marketed the drug from 1983 to 1997, the company said in September that it had no plans to relaunch and manufacture the product itself.
In a statement Tuesday, Dr. Tracy Beth Hoeg, acting director of the FDA’s Center for Drug Evaluation and Research, said the approval demonstrates the FDA’s commitment to “rapidly identifying effective treatments for ultra-rare diseases while maintaining the same standards of evidence for approval.”