Brexpiprazole in Treatment of Children and Adolescents With Irritability Associated With Autism Spectrum Disorder

Key Inclusion Criteria: * Primary Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnosis of ASD * Aberrant Behavior checklist - Irritability (ABC-I) subscale score of ≥ 18 * Clinical Global Impressions - Severity (CGI-S) scale score pertaining to irritability ≥ 4 * Mental age of ≥ 2 years as determined by Investigator based upon school participation, social history or medical records * Ability for parent/caregiver to follow all protocol procedures * Able to swallow tablets * Able to discontinue all prohibited concomitant medications to meet protocol required washouts prior to and during the trial period Key Exclusion Criteria: * Primary diagnosis of bipolar I disorder, including any DSM-5 current diagnosis of bipolar II disorder, schizophrenia, schizoaffective disorder, major depressive episode, and post-traumatic stress disorder (PTSD). Attention-deficit/hyperactivity disorder (ADHD) maybe exclusionary if it is the primary disorder, or is not stable or adequately treated. * current or historical diagnosis of Fragile-X Syndrome or Rett's Disorder * history of neuroleptic malignant syndrome * a significant risk of committing violent acts, serious self-harm, or suicide * epilepsy, a history of seizures, or a history of severe head trauma or stroke, or have a history or current evidence of other unstable medical conditions * current hypothyroidism or hyperthyroidism * uncontrolled Type I or Type II diabetes * uncontrolled hypertension or symptomatic hypotension, or orthostatic hypotension * Weight \< 15 kg * Previous exposure to brexpiprazole * Sexually active males or females, who could become pregnant, not agreeing to practice 2 different methods of birth control or remain abstinent during the trial and for 30 days at the end of the study