FDA Expands Approval of Leucovorin for Folate Deficiency, Not Autism

The Food and Drug Administration (FDA) has broadened the approval of leucovorin calcium tablets to include the treatment of cerebral folate deficiency (CFD) in patients who have a confirmed genetic variant affecting the folate receptor 1 gene (FOLR1). This marks the first approved treatment specifically for this rare and serious condition, according to an agency press release issued March 10, 2026. The decision follows a review of existing case reports, mechanistic data, and other relevant literature.

Cerebral folate deficiency is a genetic disorder that prevents the brain from properly utilizing folate, a B vitamin crucial for neurological development and function. Individuals with the FOLR1 variant experience a range of severe neurological symptoms, including developmental delays, movement disorders, and seizures. The FDA’s approval aims to address the underlying metabolic issue in these patients, offering a targeted therapeutic option.

Understanding Cerebral Folate Deficiency and the FOLR1 Gene

Folate plays a vital role in numerous bodily processes, including DNA synthesis and cell growth. In the brain, folate is essential for the proper development and function of neurons. CFD arises when the transport of folate across the blood-brain barrier is impaired. The FOLR1 gene provides instructions for making the folate receptor alpha, a protein responsible for transporting folate into cells, including those in the brain. Variants in this gene can disrupt this transport process, leading to CFD.

The FDA emphasized that this approval is specifically for CFD linked to the FOLR1 gene variant. It does not extend to other potential causes of folate deficiency or other indications, such as autism spectrum disorder. This distinction is important, as the role of leucovorin in treating autism remains a subject of ongoing research and debate, as highlighted by a perspective from Autism Speaks (detailed below).

Evidence Supporting the Approval

The FDA’s approval is based on a systematic review of available evidence, rather than a traditional, large-scale clinical trial. This approach is common for rare diseases where conducting such trials is challenging. The agency considered case reports documenting the clinical response of patients with CFD-FOLR1 to leucovorin treatment, alongside mechanistic studies explaining how leucovorin can bypass the defective folate transport system.

Leucovorin is a form of folate that can enter cells through alternative pathways, potentially compensating for the impaired transport caused by the FOLR1 variant. However, it’s crucial to understand that the evidence supporting leucovorin’s efficacy is primarily observational. While case reports suggest potential benefits, they cannot definitively prove a cause-and-effect relationship. Further research, including well-designed clinical trials, is needed to confirm these findings and establish optimal treatment protocols.

Collaboration and Label Updates

The FDA collaborated with GSK, the manufacturer of Wellcovorin (leucovorin calcium), to update the drug’s label with specific information regarding its use in patients with CFD-FOLR1. This update ensures that healthcare providers have the necessary information to appropriately identify and treat eligible patients. The label update, which occurred in September 2025 according to the FDA, reflects the growing understanding of the genetic basis of CFD and the potential role of leucovorin in managing the condition. More details on the label update can be found here.

Potential Side Effects and Safety Considerations

As with any medication, leucovorin can cause side effects. The FDA’s label lists potential adverse reactions, including pruritis (itching), rash, urticaria (hives), dyspnea (shortness of breath), rigors (shivering), impaired thermoregulation, and anaphylaxis (a severe allergic reaction). Healthcare providers should carefully monitor patients receiving leucovorin for any signs of these or other adverse effects.

Perspective from Autism Speaks

The FDA’s decision has sparked discussion within the autism community, given previous interest in leucovorin as a potential treatment for autism spectrum disorder. Andy Shih, PhD, Chief Science Officer at Autism Speaks, offered a perspective on the approval, emphasizing that the current evidence does not support the broad use of leucovorin for autism.

“Today’s decision by the FDA reflects what the science has indicated so far: that evidence for leucovorin as an effective treatment for autism remains limited,” Shih stated. “While some studies suggest that a small subgroup of children with autism who have folate receptor autoantibodies may benefit, larger and more rigorous trials are needed before this treatment can be considered broadly effective for autism.” Autism Speaks continues to advocate for evidence-based interventions for individuals with autism.

What Comes Next: Surveillance and Further Research

The FDA’s approval of leucovorin for CFD-FOLR1 is an important step forward for patients with this rare genetic disorder. However, ongoing surveillance and further research are crucial to optimize treatment strategies and fully understand the long-term effects of leucovorin. The FDA will continue to monitor reports of adverse events and assess the drug’s performance in real-world settings.

Researchers are also planning additional studies to investigate the underlying mechanisms of CFD and identify potential new therapeutic targets. These efforts will help to refine diagnostic criteria, improve treatment outcomes, and ultimately enhance the quality of life for individuals affected by this challenging condition. The Department is also coordinating flights out of the Middle East for Americans who have completed a Crisis Intake Form, as space is available, according to OSAC alerts issued March 10, 2026.