Pimavanserin for the Treatment of Irritability Associated With Autism Spectrum Disorder

Phase 2/3 Completed 237 enrolled ACADIA Pharmaceuticals Inc.

RandomizedParallel-groupQuadruple-blindTreatment

Summary

6-week, randomized, double-blind, fixed-dose, placebo-controlled, parallel group study in children and adolescents (aged 5 to17 years) with autism spectrum disorder (ASD) with irritability, agitation, or self-injurious behaviors to study the efficacy and safety of pimavanserin

Timeline

Start: 2022-08-09
Primary completion: 2024-09-27
Completion: 2024-09-27

Outcome

Missed primary endpoint

registry analysis (superiority test); Placebo vs Pimavanserin Low Dose; p = 0.2986; Mean Difference (Final Values) -1.6 (95% CI -4.6 to 1.4) NCT05523895 ↗

registry analysis (superiority test); Placebo vs Pimavanserin High Dose; p = 0.2859; Mean Difference (Final Values) -1.6 (95% CI -4.5 to 1.3) NCT05523895 ↗

paper The least squares mean (LSM [95% CI]) improvement in the ABC-I subscale score was not significantly different from placebo for either pimavanserin group PMID 42162607 ↗

Publications

Bugarski-Kirola D, Hofbauer RK, Sameljak S, Marco EJ, Sumila A, Darwish M, Ortiz S, Liu IY, Nunez R, Zhang PH, Arango C. Pimavanserin for Irritability in Children and Adolescents With Autism Spectrum Disorder: Phase 2 Randomized Trial. J Am Acad Child Adolesc Psychiatry. 2026 May 19:S0890-8567(26)00229-7. doi: 10.1016/j.jaac.2026.05.007. Online ahead of print.

Drugs

Evaluation	Drug	Modality	Dose	Route
Subject	Pimavanserin	Small molecule	10 mg	—
Subject	Pimavanserin	Small molecule	20 mg	—
Subject	Pimavanserin	Small molecule	34 mg	—