Is leucovorin (folinic acid) approved for the treatment of Autism Spectrum Disorder (ASD)?

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Last updated: September 25, 2025View editorial policy

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Leucovorin is Not FDA-Approved for Autism Spectrum Disorder

Leucovorin (folinic acid) is not FDA-approved for the treatment of Autism Spectrum Disorder (ASD), despite some emerging research showing potential benefits in specific subgroups of children with ASD.

Current Status of Leucovorin for ASD

Leucovorin is currently only FDA-approved for specific indications unrelated to ASD, including:

  • As rescue therapy after high-dose methotrexate treatment
  • For treatment of certain toxoplasmosis infections 1
  • For treatment of folate deficiency states

Research on Leucovorin in ASD

Recent research has investigated leucovorin's potential benefits in ASD, particularly in children with:

  • Cerebral folate deficiency (CFD) 2
  • Presence of folate receptor alpha autoantibodies (FRAAs) 3, 4
  • Presence of soluble folate binding proteins (sFBPs) 5

Key Research Findings:

  • A 2021 meta-analysis found that children with ASD were 19 times more likely to be positive for folate receptor alpha autoantibodies compared to typically developing children 2

  • Treatment with leucovorin has shown improvements in:

    • Communication skills (medium-to-large effect sizes) 2
    • Core ASD symptoms in individual studies 2
    • Associated behaviors like attention and stereotypy 2
    • Irritability in children positive for FRAAs 3
  • The most common adverse effects reported were generally mild:

    • Aggression (9.5%)
    • Excitement or agitation (11.7%)
    • Headache (4.9%)
    • Insomnia (8.5%)
    • Increased tantrums (6.2%) 2

Regulatory Considerations

The FDA approval process requires substantial evidence from multiple large-scale, well-controlled clinical trials demonstrating both efficacy and safety 6. Currently, leucovorin lacks this level of evidence for ASD treatment.

Similar to other medications like methotrexate, which remains unapproved by the FDA for certain indications despite widespread off-label use, leucovorin's use in ASD remains off-label 6.

Clinical Implications

Despite not being FDA-approved for ASD, some clinicians may consider leucovorin as an off-label treatment option in specific cases:

  • Children with confirmed cerebral folate deficiency
  • Children who test positive for folate receptor alpha autoantibodies
  • Children with documented abnormalities in folate metabolism

Conclusion

While emerging research suggests potential benefits of leucovorin in specific subgroups of children with ASD, particularly those with folate metabolism abnormalities, it has not received FDA approval for this indication. The American Academy of Child and Adolescent Psychiatry practice parameters for ASD do not include leucovorin among recommended pharmacological interventions 1.

Clinicians considering leucovorin for ASD should be aware of its off-label status and the need for appropriate biomarker testing to identify patients who might benefit from this approach.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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