The Largest Leucovorin-Autism Trial To-Date Has Been Retracted: What This Means for Families and Clinicians

The largest randomised trial of leucovorin for autism has been retracted due to data errors — weakening an already fragile evidence base and raising urgent questions about a treatment that gained political momentum before the science was settled.

Introduction

In January 2026, the European Journal of Pediatrics retracted what had been the largest randomised controlled trial of leucovorin (folinic acid) as a treatment for autism. The study, led by Prateek Kumar Panda and colleagues at the All India Institute of Medical Sciences, had enrolled 77 autistic children and claimed that 24 weeks of daily oral folinic acid reduced autism symptom severity compared with placebo.

The retraction matters , not only because it removes a significant piece of evidence from an already limited evidence base, but because of the extraordinary political and public attention leucovorin had received in the months before the problems were discovered. In September 2025, the US FDA announced it would approve leucovorin for treating cerebral folate deficiency associated with autism, and Health and Human Services officials called it “the first FDA-recognized therapeutic for children with cerebral folate deficiency and autistic symptoms.” Over 25,000 parents joined a Facebook group dedicated to the treatment. Doctors began prescribing off-label. Drug shortages followed.

As a consultant neurodevelopmental paediatrician and the author of Leucovorin for Autism: A Guide for Parents and Professionals, I want to set out clearly what happened, what it means for the evidence, and what families should do now. The book has been updated and resubmitted to reflect this development.

What Went Wrong With the Panda Study?

The problems were first spotted by Thomas Challman and Scott Myers, paediatricians at Geisinger College of Health Sciences, who posted concerns on PubPeer in September 2025. They noticed that numbers in the data tables did not add up correctly and that the statistical analyses contained errors.

The journal investigated. Their reviewers attempted to replicate the study’s results using the dataset provided by the authors — and could not. The European Journal of Pediatrics concluded that they “no longer have confidence in the validity of the results and conclusions reported in this article” and issued a formal retraction on 29 January 2026 (1).

Lead author Panda acknowledged “some unintentional statistical analysis errors” and stated the team is preparing a corrected manuscript for resubmission to the same journal. Of the six authors, only two agreed with the retraction; four did not respond (2).

It is worth noting that unintentional errors do happen in research. What matters is whether the corrected analysis, if and when it appears, still supports the original conclusions. Until then, the findings of this study cannot be relied upon.

Where Does This Leave the Evidence?

The retraction is significant because the evidence base for leucovorin in autism was already slim. Only five randomised clinical trials have ever tested folinic acid in autistic people. The Panda study was the largest. With its retraction, four remain — and none is large enough on its own to be conclusive:

• Frye et al. (2018) — the principal RCT, published in Molecular Psychiatry. This 12-week double-blind placebo-controlled trial of 48 children found that high-dose folinic acid (2 mg/kg/day, max 50 mg) improved verbal communication in children who tested positive for folate receptor alpha autoantibodies (FRAAs). The effect size was moderate but clinically meaningful for this specific subgroup. This remains the strongest single piece of evidence (3).

• Renard et al. (2020) — the French EFFET trial, published in Biochimie. A 12-week placebo-controlled trial of just 19 children, using a lower dose (5 mg twice daily). It reported significant improvements in ADOS scores for social interaction and communication. However, with only 19 participants, it is essentially a pilot study (4).

• Batebi et al. (2021) — published in Child Psychiatry and Human Development. A 10-week double-blind trial of 55 children in Iran. Importantly, folinic acid was used as an adjunct to risperidone, not as a standalone treatment, which makes it difficult to compare with the other trials. It reported improvements in inappropriate speech and stereotypic behaviour (5).

• Zhang et al. (2025) — published in Nutrients. A 12-week trial of 80 children in China. It reported improvements in social reciprocity, particularly in children with certain folate metabolism gene polymorphisms. However, the unequal randomisation ratio (50:30) is unusual, and the study warrants careful scrutiny (6).

All four trials are positive — but all have significant limitations: small sample sizes, short durations, and methodological concerns. A 2026 systematic review by Coghill and Guastella in CNS Drugs confirmed that the overall quality of the evidence remains low (7). The field now awaits results from Frye’s larger, NIH-funded multi-centre confirmatory trial (NCT02839915), which has not yet reported.

As Dorothy Bishop, the Oxford neuropsychologist, observed: “The statistics were all over the place… The quality of the research is uniformly poor” (2).

Dr Audrey Brumback noted that “the evidence base for using leucovorin to treat autism was already weak” and the retraction “weakens it even further” (8). David Mandell emphasised: “We don’t know whether leucovorin is a good treatment for autism. We also don’t know what the long-term effects are of taking it” (8).

The Political Context

What makes this retraction particularly consequential is the political weight that had been placed on leucovorin before the science was ready.

In September 2025, the US FDA announced expanded use of folinic acid for autism. HHS officials stated this would “authorize treatment for children with ASD, with continued use if children show language, social, or adaptive gains.” The announcement was made at a government press conference, giving leucovorin a level of official endorsement that the underlying evidence did not support (8, 9).

In October 2025, the American Academy of Pediatrics declined to recommend routine leucovorin use for autism — a notable counterpoint to the federal enthusiasm (8).

As Shafali Jeste put it: “The reason this specific drug has been of such interest is because of the publicity around it, not because we as scientists believe that this is the drug that we should be testing” (9).

Paul Offit, of Children’s Hospital of Philadelphia, was blunter, placing leucovorin in a long line of treatments — secretin, Lupron, nicotine patches — that were promoted as breakthroughs for autism before adequate evidence was available (9).

The historical parallel is instructive. Decades ago, the Fragile X syndrome community trialled leucovorin with considerable hope. The results were no better than placebo (9).

The Society for Developmental and Behavioral Pediatrics Responds

On 30 January 2026, the day after the retraction was published, the Society for Developmental and Behavioral Pediatrics (SDBP) issued a statement affirming its commitment to evidence-based care. The statement emphasised that treatment recommendations for autistic children must be grounded in rigorous, replicated research — not preliminary findings or political momentum (10).

Thomas Challman, one of the researchers who first flagged the problems, stated clearly: “Until we have acceptable evidence of safety and effectiveness, folinic acid use as a treatment for autism is not appropriate outside of a well-designed clinical trial” (2).

What Does This Mean in Practice?

For families currently using leucovorin: This retraction does not necessarily mean leucovorin is harmful or that it cannot help some children. The Frye et al. (2018) study remains unretracted and provides some evidence of benefit in FRAA-positive children with language difficulties. However, the overall evidence base is now weaker than it appeared six months ago. If your child is taking leucovorin, discuss this development with your prescribing clinician. Do not stop medication without medical advice, but do have an honest conversation about what the current evidence supports.

For families considering leucovorin: The biomarker-guided approach — testing for folate receptor autoantibodies before starting treatment — remains the only defensible clinical position. Universal use in all autistic children is not supported by the evidence. Ask your clinician: Has my child been tested for FRAAs? What evidence supports this treatment for my child specifically? What monitoring will be in place?

For clinicians: Prescribing leucovorin for autism remains off-label. The retraction reinforces that this should only occur within well-designed clinical trials, or with comprehensive informed consent that honestly represents the limitations of the current evidence. The NICE guidelines in the UK do not currently recommend leucovorin for autism.

For everyone: This episode is a reminder of what happens when political enthusiasm outpaces scientific evidence. Families deserve honest, balanced information — not premature promises. The scientific process worked here: errors were identified, investigated, and the paper was retracted. But the damage to public trust, and the clinical decisions made on the basis of flawed data, cannot be so easily corrected.

Key Takeaways

• The largest RCT of leucovorin for autism (Panda et al., 2024, N=77) has been retracted from the European Journal of Pediatrics due to data inconsistencies and unreplicable results.

• Only five RCTs have ever tested leucovorin in autistic people. With the Panda retraction, four remain — all positive but all limited by small samples, short durations, and methodological concerns.

• The best remaining evidence (Frye et al., 2018) supports benefit only in the FRAA-positive subgroup, not in all autistic children.

• The US FDA’s expanded-use announcement preceded the retraction and was not supported by the quality of evidence available.

• Families currently using leucovorin should discuss the retraction with their prescribing clinician but should not stop medication without medical advice.

• The biomarker-guided approach (FRAA testing) remains the only evidence-based path to considering leucovorin therapy.

• My book, Leucovorin for Autism: A Guide for Parents and Professionals, has been updated and resubmitted to reflect this development.

Where to Find Support

• Your child’s paediatrician or neurodevelopmental specialist — the most important conversation to have if your child is currently on leucovorin.

• National Autistic Society (autism.org.uk) — comprehensive information and helpline (0808 800 4104).

• NICE Guidelines (nice.org.uk) — evidence-based guidance on autism management in the UK.

• PubPeer (pubpeer.com) — where the data concerns were first raised publicly. Search for the Panda paper to follow the discussion.

• ClinicalTrials.gov — search “leucovorin autism” to check for ongoing properly designed trials.

References

1. European Journal of Pediatrics. Retraction notice: “Efficacy of Oral Folinic Acid Supplementation in Children with Autism Spectrum Disorder: A Randomized Double-Blind, Placebo-Controlled Trial.” Retracted 29 January 2026.

2. Bhattacharya, S. (2026). Largest leucovorin-autism trial retracted. The Transmitter / Spectrum. https://www.thetransmitter.org/spectrum/largest-leucovorin-autism-trial-retracted/

3. Frye, R.E., Slattery, J., Delhey, L., et al. (2018). Folinic acid improves verbal communication in children with autism and language impairment: a randomized double-blind placebo-controlled trial. Molecular Psychiatry, 23(2), 247–256.

4. Renard, E., Leheup, B., Gueant-Rodriguez, R.M., et al. (2020). Folinic acid improves the score of Autism in the EFFET placebo-controlled randomized trial. Biochimie, 173, 57–61.

5. Batebi, N., Sanjari Moghaddam, H., Hasanzadeh, A., et al. (2021). Folinic acid as adjunctive therapy in treatment of inappropriate speech in children with autism: a double-blind and placebo-controlled randomized trial. Child Psychiatry and Human Development, 52(5), 928–938.

6. Zhang, C., Chen, Y., Hou, F., et al. (2025). Safety and efficacy of high-dose folinic acid in children with autism: the impact of folate metabolism gene polymorphisms. Nutrients, 17(9), 1602.

7. Coghill, D. & Guastella, A.J. (2026). Can leucovorin (folinic acid) treat autism features? CNS Drugs.

8. Diament, M. (2026). Autism study of drug touted by Trump administration retracted. Disability Scoop, 17 February 2026. https://www.disabilityscoop.com/2026/02/17/autism-study-of-drug-touted-by-trump-administration-retracted/31860/

9. Neighmond, P. (2026). Can the prescription drug leucovorin treat autism? History says, probably not. NPR, 22 January 2026. https://www.npr.org/sections/shots-health-news/2026/01/22/nx-s1-5684294/leucovorin-autism-folic-folinic-acid-origins-vitamin-b

10. Society for Developmental and Behavioral Pediatrics. (2026). SDBP Affirms Commitment to Evidence-Based Care Following Retraction of Leucovorin Autism Study. 30 January 2026. https://sdbp.org/sdbp-affirms-commitment-to-evidence-based-care-following-retraction-of-leucovorin-autism-study/

11. Retraction Watch. (2026). Weekend reads: Largest leucovorin-autism trial retracted. 7 February 2026. https://retractionwatch.com/2026/02/07/weekend-reads-largest-leucovorin-autism-trial-retracted/