An open-label extension long-term study of the safety and efficacy of aripiprazole for irritability in children and adolescents with autistic disorder in Japan

Aim: The purpose of this study was to evaluate the long-term safety and efficacy of aripiprazole in treating irritability in pediatric patients (6–17 years) with autistic disorder (AD) in Japan. Methods: In this open-label extension study, patients who had completed a previous randomized, double-blind, placebo-controlled 8-week study were enrolled and were flexibly dosed with aripiprazole (1–15 mg/day) until the new indication of irritability in pediatric autism spectrum disorder was approved in Japan. Results: Seventy (81%) out of 86 enrolled patients completed week-48 assessments. The mean duration of treatment was 694.9 days. The mean daily dose of aripiprazole over the treatment period was 7.2 mg and the mean of the final dose was 8.5 mg. The most common treatment-emergent adverse events (TEAE; ≥20%) included nasopharyngitis, somnolence, influenza, and increased weight. The majority of these TEAE were mild or moderate in severity, and there were no deaths, and no clinically relevant findings in laboratory values except prolactin decrease, vital signs, height, or ECG parameters. At week 48 (observed case), the mean change from baseline in the Irritability subscale score for the Aberrant Behavior Checklist Japanese Version was −6.3 in prior placebo patients and −2.6 in prior aripiprazole patients. Conclusion: Aripiprazole was generally safe, well tolerated, and effective in the long-term treatment of irritability associated with AD in Japanese pediatric patients.