What is leucovorin? Inside the drug giving new hope to autism patients

Can a generic drug designed to make chemotherapy work better benefit people with autism?

President Trump is touting an “amazing” drug — leucovorin — as “an answer to autism,” a broad range of conditions that affect how people learn, behave, communicate and interact with others.

A form of vitamin B9, also known as folate, leucovorin has been prescribed to protect healthy cells from the toxic side effects of chemotherapy, to enhance chemotherapy and to treat cerebral folate deficiency.

Folate is needed for brain development. Research has found that some children with neurodevelopmental disorders show signs of cerebral folate deficiency, a shortage of B9 in the brain.

“If you’re going to the doctor and looking for an autism pill, it doesn’t exist,” Dr. Richard Frye, a pediatric neurologist researching leucovorin as a potential autism treatment, previously told The Post. “But leucovorin has helped a lot of children.”

What is autism?

Around 1 in 36 US children is believed to have some form of autism.

Evidence suggests that genetic and environmental factors may contribute to the risk of developing it. Researchers have spent decades trying to pinpoint those exact factors.

Trump said his administration will reveal how autism “happens, so we won’t let it happen anymore.”

Diagnoses in the US have skyrocketed in recent years, increasing by 175% between 2011 and 2022.

Experts have blamed the spike in diagnoses largely on greater awareness of autism, improved screening and updated diagnostic criteria.

How could leucovorin help?

Leucovorin costs about $100 per month without insurance and even less with coverage.

Supporters are hopeful that the medication delivers folate effectively and efficiently to the brain to improve communication and language skills.

Scientists have found that some children with neurodevelopmental disorders carry folate receptor alpha (FR⍺) autoantibodies, which block the proper transport of folate into the brain.

One study found that more than 75% of children with autism had FR⍺ autoantibodies, compared to just 10% to 15% of children without autism.

In a 2012 clinical trial, leucovorin was tested on 44 children with autism and FR⍺ autoantibodies. One-third of those treated with the drug showed significant language improvement.

In one recent, exciting case, a toddler with nonverbal autism — whose parents had been told their child would never speak — uttered his first words just three days after starting the drug.

What are the downsides?

The process to obtain leucovorin begins with a blood test that detects autoantibodies blocking a receptor essential for transporting folate into the brain.

Those who test positive are significantly more likely to respond to treatment.

Despite these promising findings, scientists and doctors caution that leucovorin is still an experimental treatment, suitable only for individuals with a specific genetic or metabolic profile.

The Autism Science Foundation does not endorse leucovorin as a treatment for autism, saying in a statement that “more studies are necessary before a conclusion can be reached.”

Side effects may include gastrointestinal distress, weakness, fatigue, decreased appetite, changes in taste and hair loss. Allergic reactions, seizures and infections may occur in rare but severe cases.

The long-term effects of the drug remain unknown.

Frye noted that leucovorin on its own isn’t a cure-all. While his patients were taking the medication, they also continued other therapeutic interventions, such as applied behavior analysis and speech therapy.

“You have to treat a lot of things to make the body well,” Frye said. “What [leucovorin] does, we think, is accelerate the effectiveness of all these therapies.”

In addition to language comprehension, Frye is interested in exploring how leucovorin can mitigate other symptoms associated with autism, such as difficulty socializing.

Meanwhile, the Trump administration is expected to announce that using acetaminophen while pregnant can raise the odds the baby will have autism.

Major health organizations have said that acetaminophen (Tylenol is one brand name) is safe for use in pregnancy.