Yamo Pharmaceuticals is advancing its experimental oral autism drug L1-79 to Phase 3 clinical trials in the United States after receiving more than 6,000 inquiries from families in over 90 countries during the past two weeks.
Founded in 2015 to develop L1-79, the privately held company announced last week that the final trial stage is expected to begin in early 2027. Yamo has discussed its Phase 2 results with the Food and Drug Administration (FDA) and will meet the agency again in December to finalize protocols for a 16-week randomized, double-blind trial with more participants treated over a longer period.
"Every one of these inquiries represents a family hoping for a treatment for the core symptoms of autism," Yamo Chief Executive Officer Chuck Bramlage said in a press release, with the company expecting the influx to speed up enrollment.
L1-79 could become the first FDA-approved therapy for the underlying neurological core features of autism spectrum disorder (ASD), which affects about one in 31 U.S. children. In Phase 2 trials testing efficacy, safety, and adverse reactions on a midsize patient group, the FDA granted L1-79 Fast Track designation. While that does not shorten clinical trials, it allows priority review within six months instead of the standard 10-month timeline.
So far, 116 patients have joined three clinical trials for L1-79, which responders' families have dubbed the "Ozempic for autism." Among its earliest successes is Joshua Turteltaub, now 27, who was diagnosed with autism at two and a half years old and had his first breakthrough a week after starting the drug in December 2015.
Joshua Turteltaub and the 2015 clinical trial
While many autistic people live independently, Joshua needs lifelong support and daily care like a four-year-old, requiring prompts to brush his teeth and shower and having all meals made for him. Mostly nonverbal with a "minimal" vocabulary, his inability to communicate caused profound anxiety and kept him from sleeping through the night for years.
His parents, lawyers Linda and Jim Turteltaub, had not expected an autism diagnosis. Their eldest son, Jacob, now 29 and a Spanish-fluent lawyer, overcame childhood speech delays through early intervention. When Joshua had similar delays, Linda said: "I thought, 'OK, I know the protocol.' But it turned out he needed a lot more."
Diagnosed at two and a half, Joshua started speech and applied behavioral analysis therapy to build functional skills like nonverbal communication and age-appropriate play in small incremental steps. Having attended special autism schools from preschool through adulthood, he now attends the adult disability program New Beginnings for Tomorrow.
By December 2015, when Joshua was 16, therapy and medication kept his anxiety and sleep issues somewhat at bay, though far from perfectly. When his psychiatrist of eight years, autism specialist Dr. Eric Bartky, asked Linda and Jim to try L1-79, they hesitated because Joshua had to stop all other medications and risk unknown side effects, but decided to proceed. "We just wanted something to address the issues, to try and get him better so that he can at least communicate with us," Linda told the Daily Mail.
Breakthroughs at the Bronx Zoo and family funeral
One week after starting L1-79, Joshua uttered the word "movie" while watching a film with his parents at the Bronx Zoo, a moment Linda remembers more than a decade later. "My husband and I looked at each other like, 'Oh my gosh.' He'd never said that before," she told the Daily Mail, adding: "Joshua had said very few words prior to 2015. He usually repeats the words we say."
A few weeks later, Joshua bade Bartky farewell for the first time when leaving his office. "I thought his parents were going to faint," Bartky, a principal investigator in two FDA trials for L1-79, told the Daily Mail. "I almost fainted because he had never said anything. He had never said words or those words, ever."
Soon afterward, Joshua experienced loss for the first time when his grandfather, with whom he shared a special bond, died. Though Joshua always struggled to stay at ease, he sat calmly through the funeral. "I expected I would have to get up and leave with Josh because he was going to be fidgeting," Linda said. "[Instead] he was calm the entire time. That was very unusual for him."
Bartky said: "He behaved wonderfully at the funeral. He really seemed to understand the seriousness of being at a funeral and feeling that emotion." In trial exercises and puzzles, researchers also had Joshua stack wooden blocks. Where falling blocks previously made him frustrated and agitated, on L1-79 he was more focused, piled them higher, and was joyful when they fell.
Because trial participants could take L1-79 only briefly, Joshua had to stop the single daily pill after 28 days and immediately regressed. "We've had to go back on all kinds of meds for his anxiety. You can't believe how many meds he's on," Linda said, adding: "I'm a lawyer, and even I would sign anything to get him back on." The family hopes he can resume L1-79 after Phase 3.
How L1-79 targets core autism symptoms
No single drug currently treats ASD's core features. "The current FDA-approved medications [for autism] on the market are for treating irritability," Bartky said, referring to the antipsychotics aripiprazole and risperidone, which manage aggression, temper tantrums, and mood changes.
According to Yamo, L1-79 selectively inhibits tyrosine hydroxylase, the enzyme controlling dopamine and norepinephrine production, reducing those chemical messengers to balance hyperactive pathways behind sensory overload and social withdrawal.
"What makes L1-79 different is that L1-79 treats the core symptoms of autism, things like socialization and communications, things that go along with that like eye contact, reciprocal conversation, nonverbal communication, such as reading social nuance. These are things that are extremely important for a person's emotional growth and functioning in society," Bartky said, noting that patient results vary dramatically across the spectrum.
Bartky also called L1-79's safety profile "remarkable." Unlike existing drugs that risk dyskinesia (involuntary, sometimes permanent erratic movements), hypertension, and metabolic syndrome (five conditions raising heart disease, stroke, and Type 2 diabetes risk), L1-79 has "not had one single serious side effect." He added: "We've had over 100 participants in the FDA studies, and there have been no serious side effects to date."
Expanded access and calls for faster FDA approval
Although FDA trials previously required patients to be aged 12 to 21, the agency granted Bartky expanded access for two younger patients after he argued they had life-threatening needs L1-79 could immediately address. One was four-year-old Lev Bielski, a compulsive self-harmer who had a "life-changing transformation." His father, Matt Bielski, called L1-79 "the Ozempic of autism" after it made Lev "the most affectionate kid almost overnight."
Bartky is urging the federal government and Health and Human Services Secretary Robert F. Kennedy Jr., who has yet to comment publicly on L1-79, to speed up approval. "As a clinician researcher, every day I have patients with autism in my office that I could be prescribing this to. This is all lost time," Bartky said.
