The history of autism "cures" is a history of dashed hopes and frequent danger.
The theory behind treating autism with leucovorin is that the drug gives autistic kids something they’re missing. Children with autism seem to be more likely than other children to produce an antibody that prevents folate, also known as vitamin B9, from reaching their brain. Because folate plays a role in brain development, some researchers—most notable among them Richard Frye, a doctor who has been prescribing and promoting leucovorin for nearly two decades, and who told me he spoke with leaders in the Health and Human Services Department before the press conference—think these antibodies might hamper the growth of a child’s language abilities. Leucovorin is essentially a massive dose of folate, delivered in a form that can bypass those antibodies....But that theory, which has long been debated in autism subreddits and Facebook groups, hasn’t gained traction among mainstream autism scientists. They point to a 2018 study that found that autistic children and their non-autistic siblings were equally likely to have these antibodies. The clinical evidence for leucovorin’s effectiveness for autistic kids is limited to a handful of small studies that don’t measure the same outcomes. No large, randomized, placebo-controlled trial has ever been conducted. If you want to get the drug for autism, it has to be prescribed off-label, which many doctors refuse to do....Several researchers I spoke with compared the excitement about leucovorin to the enthusiasm for secretin, another drug that was popular as an autism treatment in the 1990s after early promising results. More rigorous clinical trials later showed that it wasn’t effective. [AFH chief science officer Alycia] Halladay said she’s heard from multiple doctors, including her child’s pediatrician, that they’ve been besieged with calls from parents hoping to get a prescription. One doctor in Chicago told me he had received dozens of inquiries....
Offline, parents have been calling Frye, the longtime leucovorin doctor, who believes that as many as 1 million kids could benefit from the drug. He mostly treats children with significant language delays, though he says that the drug can sometimes help higher-functioning kids too. Frye was the lead author of a small 2016 study that found that children with autism who received leucovorin showed improvements in verbal communication, compared with those given a placebo; he also recently published a book called The Folate Fix. Ever since the press conference, his office has been inundated with calls and emails from parents who want the drug for their children.
For years, Frye has had a backlog of patients wanting to see him, but the White House announcement, he told me, made an “impossible situation worse.” He already has about 1,000 patients who are taking leucovorin, and he isn’t planning to accept any new ones until 2028. According to Frye, the FDA has asked him to submit an application to conduct clinical trials on leucovorin as an autism treatment, but last week, he told me that “not much is going on at this time.” He guesses those trials will take about two years. In the meantime, parents will be left to experiment with leucovorin on their own.
