MapLight ML-004 Misses Phase 2 Primary Endpoint, Shows Irritability Signal

MapLight Therapeutics announced on June 22, 2026, that its investigational drug ML-004 failed to meet its primary endpoint in a Phase 2 trial for autism spectrum disorder (ASD). The drug did not achieve statistical significance on the Social Withdrawal subscale of the Aberrant Behavior Checklist (ABC-SW). Despite missing the primary endpoint, ML-004 demonstrated a statistically significant improvement in the Irritability subscale (ABC-I) among adolescent participants. MapLight, whose drug is a selective muscarinic M4 receptor positive allosteric modulator (PAM), plans further data analysis and discussions with regulatory authorities regarding these findings.