MapLight's ML-004 autism trial misses primary endpoint; adolescent irritability signal reported
MapLight Therapeutics reported topline results from its Phase 2 IRIS trial of ML-004 in autism spectrum disorder, announced June 22, 2026. The study did not meet its primary endpoint on social communication deficits, but a prespecified analysis in adolescents with moderate-to-severe irritability showed improvement over placebo, and the company plans to meet with the FDA to determine the development path.
Key points
- Primary endpoint (ABI-SC social communication domain) was not met; no statistical separation from placebo on that measure.
- In adolescents with baseline ABC-I score of 16 or higher (N=20), care-partner-reported ABC-I improved over placebo: effect size 1.33, nominal p=0.013.
- Two adolescents (3.9%) on ML-004 discontinued due to an adverse event versus none on placebo; no severe or serious adverse events occurred with ML-004.
- The company expects to engage the FDA in an End-of-Phase 2 meeting; the trial enrolled 161 participants, including 102 adolescents.
The filing
Written by AI on Nov 9, 2026, 11:43 AM ET, from this filing only. Written later: this filing was briefed after the fact, when past filings were added to the site, so the brief may be read with hindsight; the filing itself is the record of what was known on June 22, 2026.
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