MapLight Therapeutics, Inc. (MPLT) announced topline results from its Phase 2 IRIS study evaluating ML-004 in patients with autism spectrum disorder (ASD). The trial did not meet its primary endpoint measuring improvement in social communication deficits, but exploratory analyses revealed encouraging signals in a subgroup of adolescents with higher baseline irritability.
The IRIS study enrolled 161 participants (102 adolescents and 59 adults) and was designed to explore multiple clinical endpoints, including social communication and irritability. The primary endpoint, change from baseline to week 12 in the caregiver-reported Autism Behavioral Inventory (ABI)-Social Communication Domain score, showed no statistically significant difference versus placebo.
However, in a prespecified subgroup analysis of adolescents aged 12-17 with moderate to severe irritability at baseline (ABC-I = 16), ML-004 demonstrated clinically meaningful improvement over placebo on the care-partner-reported Aberrant Behavior Checklist-Irritability (ABC-I) subscale (effect size 1.33, nominal p=0.013). Consistent improvement was also observed in the clinician-rated CGI-I irritability domain (effect size 1.08, nominal p=0.036).
ML-004 was well tolerated, with no severe or serious adverse events reported in the active treatment arm. No extrapyramidal symptoms were observed, and mean weight gain was lower than in the placebo group.
Following a full review of the data, MapLight plans to meet with the U.S. FDA for an End-of-Phase 2 meeting to determine the next steps for ML-004's development. The company remains well-capitalized ahead of upcoming Phase 2 ZEPHYR trial results for ML-007C-MA in schizophrenia, expected by mid-August 2026.
MPLT has traded between $12.24 and $33.28 over the past year. The stock is currently trading at $30.86, up 7.08%.
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