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Clinical trial

L1-79, an experimental medicine for social skills in teens and young adults with autism: early trial results

Published 8 October 2026 · 2 min read

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A caregiver asked us to look into this.

Researchers tested an experimental pill called L1-79 in 58 people with autism, ages 12 to 21. Everyone took both the pill and a dummy pill (a placebo) at different times. The company reports that social skills scored higher while people were taking L1-79 and that there were no serious side effects. These results come from a conference presentation and company statements, not yet from a full published paper. The study did not include children under 12.

What this research found

  • Doctors rated participants' autism symptoms as less severe while they were taking L1-79 than while they were taking the placebo.
  • Parents and caregivers reported noticeable improvement in the three symptoms that bothered their loved one most.
  • The company reports that no serious side effects occurred and that no one stopped taking L1-79 because of side effects. The sources do not describe minor side effects in this trial.
  • Earlier, smaller work pointed the same way. A short 28-day phase 2 study reported by the company in 2018 saw positive trends, and the FDA gave L1-79 "Fast Track" status, which speeds up review but is not approval. A 2019 published case series of a small group reported three mild side effects that went away without a change in treatment. Its authors said the results needed to be confirmed in double-blind studies.

What this means for caregivers

  • L1-79 is not approved by the FDA and is not available as a regular prescription. The company says it is planning a larger phase 3 trial.
  • These results do not show how L1-79 would work for younger children, since the participants were 12 and older.
  • If you are curious about the research, a doctor who knows your child can help you weigh it. Trial listings, such as the one on ClinicalTrials.gov, explain who can take part. The trial described here is no longer recruiting.

Important caveats

  • The main findings come from a conference presentation and company statements. The sources do not show that the full results have been published in a journal or checked by independent experts.
  • The drug's maker paid for the study, and a company executive who helped lead it described the results as remarkable. Independent teams have not yet confirmed them.
  • The study was small (58 people) and short (12 weeks). It cannot tell us about long-term safety or whether any benefit lasts.
  • People with a cognitive test score below 70 and people with Fragile-X or Rett syndrome were not eligible. People taking certain medicines, such as alpha-2 agonists or beta-blockers, also had to stop them first. The results may not apply to all autistic young people.
  • A higher score on a social skills measure is not the same as proof that daily life or independence improved for any one person.

The science behind it

This part is written for researchers, so it gets technical. Reading it anyway is what researchers do: checking how a finding was reached, not just what it says. It’s slow going at first and gets easier after your first few articles. Skipping it is fine too.

A phase 2, double-blind, placebo-controlled crossover trial (NCT05067582) randomized 58 participants aged 12 to 21 with ASD to L1-79 (200 or 300 mg twice daily) or placebo, with a washout before crossover. The sponsor reported a mean 7.94-point improvement on the Vineland-3 Socialization Standard Score versus placebo, about twice the minimal clinically important difference, along with lower clinician-rated severity (CGI-S). Evidence is preliminary: the results were presented at INSAR 2025 and in sponsor press materials, the sponsor employs a co-lead investigator, and no peer-reviewed report of the trial appears in these sources.

At a glance

Sample size: 58 participants
Demographics: People with autism aged 12 to 21. Eligibility required a standard score of 70 or above on a cognitive test (WASI-II), so people with intellectual disability were likely not included. Sex and ethnicity breakdowns were not reported in the sources.
Key outcome: Average social-skills score was 7.94 points higher on L1-79 than on placebo, which the sponsor says is nearly double the smallest change experts consider meaningful.
Methodology: A 12-week randomized, placebo-controlled crossover phase 2 trial in teens and young adults with autism, paid for by the drug's maker and known only from a conference presentation, press materials and a trial listing.
Researchers: J. Thomas Megerian, MD, PhD (co-lead investigator; Chief Medical Officer of the sponsor)
Institutes: Yamo Pharmaceuticals LLC (sponsor), 7 trial sites (not named in the sources)

Sources

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Reviewed by Bhavin Solanki, caregiver parent. This is informational content, not medical advice — see our disclaimer.