The FDA approved leucovorin for cerebral folate deficiency affecting fewer than one in a million people, walking back earlier claims the drug could help “hundreds of thousands” of autism patients 1.
The narrow approval highlights how regulatory agencies can scale back initial policy promises when scientific evidence proves insufficient for broader applications.
Key Takeaways
- FDA approves leucovorin for ultra-rare genetic condition only
- Approval covers fewer than 50 documented cases worldwide
- Earlier autism claims lacked sufficient scientific evidence
Market Context and Regulatory Shift
The Food and Drug Administration’s Tuesday decision represents a significant retreat from September claims when officials suggested leucovorin could benefit massive numbers of children with autism. FDA Commissioner Marty Makary previously said the drug would help “hundreds of thousands of kids” with autism symptoms 2.
Instead, the agency approved leucovorin only for cerebral folate transport deficiency caused by mutations in the FOLR1 gene. This ultra-rare condition affects an estimated one in one million people, with fewer than 50 cases ever identified globally 3.
Scientific Evidence Gaps
“Right now, we don’t have sufficient data to say that we could establish efficacy for autism more broadly,” a senior FDA official said during a Monday briefing 4. The agency conducted a systematic review but found the strongest evidence only supported treatment for the rare genetic form of folate deficiency.
The approval followed an unusual path, relying on published case reports rather than randomized controlled trials. Patients with the genetic defect showed an 87% clinical response rate to leucovorin treatment, according to FDA officials 5.
Prescription Surge and Market Impact
Following the September White House announcement, leucovorin prescriptions for children aged five to 17 surged 71% in 11 weeks, according to a Lancet study 6. The increased demand created shortages, forcing some families to seek unregulated over-the-counter alternatives.
GlaxoSmithKline (GSK.L), which originally developed the branded version Wellcovorin, confirmed it will not resume manufacturing despite the new approval. Generic versions remain available to fill market demand 5.
Clinical and Investment Implications
The American Academy of Pediatrics had declined to recommend routine leucovorin use for autism, citing “too limited” evidence for broad application 5. A key randomized trial supporting autism treatment was recently retracted due to data errors, further weakening the scientific foundation.
Dr. I. David Goldman, a retired medical professor who has studied folate deficiency, said there’s no overlap between the rare genetic condition and autism. “The damage is done, because parents with autistic kids are desperate,” Goldman told CNN 3.
Policy and Market Outlook
The FDA’s measured approach contrasts sharply with the Trump administration’s initial enthusiasm for expanding leucovorin access. Health Secretary Robert F. Kennedy Jr. had called it “an exciting therapy that may benefit large numbers of children who suffer from autism” 4.
The agency remains open to future submissions studying leucovorin for autism but emphasized that companies would need to provide stronger clinical evidence. Current off-label prescribing remains at physician discretion.
Not investment advice. For informational purposes only.
References
1“FDA approves new use of the drug leucovorin – but not for autism”. NBC News. Retrieved March 10, 2026.
2Joseph Choi (March 10, 2026). “FDA approves Wellcovorin for ultra-rare disease. The Trump admin touted it as a treatment for autism”. The Hill. Retrieved March 10, 2026.
3Brenda Goodman (March 10, 2026). “FDA declines to endorse leucovorin for autism, walking back earlier statements suggesting benefit”. CNN. Retrieved March 10, 2026.
4Carmen Paun (March 10, 2026). “FDA backs away from RFK Jr.’s claims about drug’s promise for autism patients”. POLITICO. Retrieved March 10, 2026.
5Angus Liu and Darren Incorvaia (March 10, 2026). “FDA approves leucovorin for ultrarare cerebral folate deficiency subset without clinical trial”. Fierce Pharma. Retrieved March 10, 2026.
6Annika Kim Constantino (March 10, 2026). “FDA approves leucovorin as first drug for rare genetic disorder, after touting it as autism treatment”. CNBC. Retrieved March 10, 2026.