A father says an experimental autism drug transformed his four-and-a-half-year-old son’s behavior almost overnight, helping him connect with a family he had struggled to engage with.
Lev Bielski was hurting himself, making little eye contact, and withdrawing from his family, according to his father, Matthew. After receiving L1-79 through the FDA’s expanded-access program, his parents say they began seeing a dramatic difference.
“It was the next day,” Bielski told the New York Post. “It was right away and other people in all the phases said the same thing.”
“It changed everything for us,” he said.
The drug, developed by Yamo Pharmaceuticals, is intended to improve social interaction, an area that existing FDA-approved autism medications do not directly address. It remains experimental and has not received FDA approval.
Bielski, a Wall Street executive, has become an outspoken advocate for L1-79, predicting it could become the “Ozempic of autism.” He and his wife have also personally invested in Yamo.
Yamo describes L1-79 as a twice-daily oral treatment targeting core social symptoms of autism. The company says it received FDA Fast Track designation and is moving toward phase three trials in 2027.
Currently approved autism medications treat associated symptoms, such as irritability, rather than the condition’s core difficulties with social interaction and communication.
Early studies of L1-79 have reported improvements, though further testing is needed. A 2019 case series published in Clinical Therapeutics followed eight people with autism who received the drug for eight weeks. Seven showed improvements on behavioral rating scales, and four of the six assessed with a separate autism diagnostic tool also improved. The authors said the findings needed confirmation in double-blind studies.
In a later phase two trial involving 58 adolescents and young adults, Yamo reported statistically significant and clinically meaningful improvements in socialization scores compared with a placebo during the trial’s first treatment period.
Yamo Chief Medical Officer Dr. Tom Megerian described L1-79 as “a new treatment candidate aimed at social connection, not a cure,” according to the company.
Before receiving the drug, Lev was at risk of requiring more restrictive measures to prevent him from hurting himself, the Post reported. Now, his father says, Lev plays with his older sister, enjoys swimming and cuddling with his parents, and is more engaged with the people around him.
“He went from the least affectionate kid to the most affectionate kid almost overnight,” Bielski said.
Other families featured in the Post’s report described improvements in communication and social interaction while their children received L1-79.
In a video cited by the Post, one parent, Corrie Niesse, said her daughter, Payton, began talking much more after taking the drug and that she was able to have conversations with her. Payton later said she wanted to resume taking the medication.
Yamo is seeking additional funding for phase three trials. Bielski says he wants to help the company test the treatment on a larger scale.
He has also launched an Autism Impact ETF through his investment firm, Defiance ETFs, which has pledged to donate all of the fund’s net advisory profits during its first two years to autism-related causes.
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