Screening Period (Visit 1) Subjects will undergo a screening period up to 30 days prior to entering the Treatment Period.~Double-Blind Treatment Period (Visit 2 through Visit 6) Eligible subjects will be randomized in a blinded fashion to Azstarys® or placebo at the start of the Treatment Period. Randomization will be applied separately in each cohort and stratified by gender.~Cohort 1: Subjects 4 and 5 years (<6 years) will start at 13.1 mg/2.6 mg or matching placebo and may be titrated up or down to doses of 13.1 mg/2.6 mg, 26.1 mg/5.2 mg, or 39.2 mg/7.8 mg Azstarys® or matching placebo approximately each week through Visit 5~Cohort 2: Subjects 6-12 years (<13 years) will start at 39.2 mg/7.8 mg or matching placebo and may be titrated up or down to doses of 26.1 mg/5.2 mg, 39.2 mg/7.8 mg, or 52.3 mg/10.4 mg Azstarys® or matching placebo approximately each week through Visit 5
This is a multicenter, dose-optimized, randomized, double-blind, efficacy and safety study with Azstarys® in children 4 to 12 years of age with attention-deficit/hyperactivity disorder (ADHD). Azstarys® contains dexmethylphenidate (d-MPH) and serdexmethylphenidate (SDX), a prodrug of d-MPH and is orally adminstered. The primary objective is to determine the efficacy of Azstarys® compared to placebo in treating children ages 4 to 12 years old with ADHD. The study will consist of two randomized and blinded treatment cohorts ages 4 to 5 years of age and 6 to 12 years of age. 130 and 100 subjects will be enrolled respectively. Approximately 20 sites will participate.