KP415P02A Multicenter, Dose-Optimized, Open-Label, Safety/Tolerability and Pharmacokinetic Study With Azstarys® in Children 4 and 5 Years of Age With Attention-Deficit/Hyperactivity Disorder

• Screening Period: New subjects will undergo a Screening Period up to 30 days prior to entering the Dose Optimization Phase. • Dose Optimization Phase: During the 3-week Dose Optimization Phase, subjects will start at 13.1 mg/2.6 mg, and may be titrated to doses of 26.1 mg/5.2 mg or 39.2 mg/7.8 mg Azstarys® capsules based on individual tolerability and best dose-response in the opinion of the Investigator. • Treatment Phase: Eligible subjects will receive single daily doses of Azstarys® for approximately 360 ±20 days (approximately 12 months). The starting dose of Azstarys® in the Treatment Phase will be the same as the optimized dose of Azstarys® at the end of the Dose Optimization Phase, either 13.1 mg/2.6 mg, 26.1/5.2 mg, or 39.2 mg/7.8 mg per day. The daily dose may be changed at any time to any of the allowed dose levels (13.1 mg/2.6 mg, 26.1/5.2 mg, or 39.2 mg/7.8 mg per day) at the Investigator' discretion, based on individual tolerability and dose response.