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 certain adults and children.
The move comes months after the Trump administration touted Leucovorin as a potential therapy for a broader group of patients with symptoms of autism spectrum disorder. The claim sparked skepticism among some medical professionals and researchers, but raised eyebrows among families and led to a surge in prescriptions of the drug in the United States
An FDA official told reporters Monday that “we don’t have enough data to say we could demonstrate efficacy in autism more broadly,” but said the agency was open to interest from companies 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 studies suggest that leucovorin may be effective as an off-label treatment for children with autism, and some families have reported that it has helped their nonverbal children develop more language and social skills.
FDA officials, who requested anonymity to discuss the decision, told reporters on Monday that they began a comprehensive review of leucovorin as an autism treatment before narrowing its approval to a smaller population with cerebral folate deficiency, a rare genetic mutation that prevents folate – an important vitamin – from properly reaching the brain.
The condition has similar characteristics to autism, typically occurs in young children under 2 years of age, and can cause severe developmental delays, seizures, lack of muscle control and other serious neurological complications.
The officials said the FDA determined that the use of leucovorin in patients with the condition provided the “high-quality data” to support expanded approval, which will apply to both generic versions of the drug and GSK’s old brand drug Wellcovorin.
“Those were the data where we saw the largest effect sizes,” an FDA official said on the call. “So we narrowed down to this population simply because we felt that was both the strongest scientific case and the largest treatment effect that could be used, and then overcome some of the limitations in the data sources.”
Approval was based on a systematic review of the published literature in the field, including patient case reports, but not on a randomized controlled clinical trial. The same official acknowledged that bias can occur in systematic reviews, but emphasized that the treatment effects were so large that they outweighed these concerns.
The FDA is encouraging existing manufacturers of leucovorin to increase production to meet higher demand for the drug, the officials added. While GSK originally marketed the drug from 1983 to 1997, the company announced in September that it had no plans to relaunch the product and manufacture it itself.
In a press release on 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 extremely rare diseases while maintaining the same standards of evidence for approval.”
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