The Trump administration has included a drug known as leucovorin in efforts to alleviate certain autism symptoms. However, experts specializing in autism largely agree that additional research is needed before it can be widely used in children and adults.

Leucovorin, or Folinic Acid, is a synthetic variant of vitamin B9 requiring a prescription. It is primarily administered to cancer patients via IV alongside chemotherapy.

On Monday, the Food and Drug Administration revealed that it is moving forward with the approval of a tablet formulation for specific autistic patients.

Many researchers have raised concerns that this approval may be hasty, given that only a few small trials—mostly conducted outside the US—demonstrate its effectiveness in children with autism.

Several experts informed NBC News that FDA approval might create unrealistic expectations for families. This is particularly concerning as not all children with autism are eligible for prescriptions, and the likelihood of achieving positive results remains uncertain.

Researchers have long sought medications that can effectively mitigate autism symptoms; however, very few have satisfied the FDA’s rigorous safety and efficacy criteria. Prior to Monday, the FDA had only authorized two medications to address bothersome symptoms associated with autism, none of which targeted issues related to communication, social interactions, or repetitive behaviors.

Alycia Halladay, Chief Science Officer of the Autism Science Foundation, commented that her organization supports research grounded in evidence; leucovorin is not suggested as a treatment and more research is essential.

“Leucovorin doesn’t meet the standards set for FDA approvals, yet this administration is proceeding regardless. Therefore, I wouldn’t label this a victory,” Halladay remarked.

She further noted that the way the drug was presented at Monday’s White House Briefing as a major breakthrough for families with autism doesn’t align with the nuances of FDA approval.

The FDA stated in a news release that the drug is being approved for patients suffering from cerebral folate deficiency, a rare neurological disorder marked by low levels of vitamin B9 (folate) in the brain. Some researchers speculate that this condition might be linked to autism, but it is not present in all autistic individuals.

(Halladay estimates that around 10-30% of autistic patients may have this condition.)

Though leucovorin can potentially aid in reaching the brain, theoretically improving verbal communication and alleviating autism symptoms like irritability and repetitive actions, there is no evidence to suggest it entirely eradicates these symptoms.

“We still hope that leucovorin might serve as a helpful option for a subset of patients,” noted Dr. Rachel Forlomer, an assistant professor of pediatrics at Northwestern University’s Feinberg School of Medicine. “However, I can’t say we’re at a stage where we can confidently claim we can assist every individual with autism.”

President Donald Trump expressed at a briefing that the approval “offers hope for many parents of children with autism that life improvement is possible.” Mehmet Oz, leader of the Centers for Medicare and Medicaid Services, described the decision as “life-saving.” FDA commissioner Marty McCurry remarked, “I believe hundreds of thousands of children will benefit.”

However, in a follow-up news release, the Department of Health and Human Services clarified that leucovorin is “not a cure” for autism and “may only result in improvements in speech-related deficits for a subset of children.”

David Mandel, a professor of psychiatry at the University of Pennsylvania, remarked that the folate hypothesis is based on relatively weak scientific evidence.

“We lack robust large-scale studies demonstrating that a significant number of individuals with autism suffer from folic acid deficiency,” he noted.

While leucovorin has shown minimal side effects in cancer patients, higher doses can lead to gastrointestinal issues and increase the risk of seizures in individuals on anti-seizure medications. It is commonly part of treatment for colorectal cancer and other gastrointestinal malignancies, often enhancing the efficacy of the chemotherapy drug 5-fluorouracil. In rare cases, it is administered to reduce side effects from another chemotherapeutic agent, high-dose methotrexate.

Halladay mentioned observing side effects during the leucovorin autism trial but noted that the specific safety of the drug was not evaluated. She indicated that dosages varied across studies, making it difficult to determine if leucovorin was responsible for any symptom improvement, as some trial participants also received behavioral therapy.

According to Mandel, the largest study involving these trials included only 80 participants.

“For FDA approval, one would ideally want hundreds of children involved in these trials,” he explained.

Leucovorin must overcome one final obstacle before it becomes available to select autistic patients. The FDA stated it is collaborating with GSK, the manufacturer of the brand-name version of leucovorin, to update the drug’s labeling. GSK confirmed that a new application will be submitted to include autism indications.

Oz stated on Monday that leucovorin prescriptions will be covered by Medicaid, with private insurance companies likely to follow suit.

However, Mandel expressed concern that anticipated cuts to Medicaid may compel many families to cover costs out of pocket, potentially driving them to purchase folinic acid supplements online without prescriptions. Such supplements may not have gone through quality control, and dosage information could be unclear.

Dr. William Dahoot, chief science officer at the American Cancer Society, expressed concern that the growing interest in leucovorin for autism might adversely impact its availability for cancer patients.

“We have faced shortages of this drug before, and an increase in demand could lead to future shortages,” he noted in an email.