A Safety/Tolerability and PK Study With Azstarys® in Children With ADHD

Inclusion Criteria

• New Subjects must be at least 4 years old and less than 5 years and 10 months old at Screening.
• Subjects must have a body weight within the 5th and 95th percentile according to the gender-specific weight-for-age percentile charts from the Centers for Disease Control and Prevention (CDC).
• Subject must be in general good health defined as the absence of any clinically relevant abnormalities as determined by the Investigator based on physical examinations, vital signs, ECGs, medical history, and clinical laboratory values (chemistry, hematology and urinalysis) at Screening.
• At least one parent/legal guardian of the subject must voluntarily give written permission for the subject to participate in the study.
• Subject must meet Diagnostic and Statistical Manual of Mental Disorders - Fifth Edition (DSM-5) criteria for a primary diagnosis of ADHD (combined, inattentive, or hyperactive/impulsive presentation) per clinical evaluation and confirmed by the Mini-International Neuropsychiatric Interview for Children and Adolescents (MINI Kid).
• Subject must have had ADHD symptoms present for at least 6 months prior to the Screening Visit.
• Subject must be able and willing to wash out current stimulant ADHD medications, including herbal medications from 5 days prior to the start of the Dose Optimization Phase, and abstain from taking these to the end of the Treatment Phase (Visit 17) or Early Termination (ET); and wash out non-stimulant ADHD medications from 14 days prior to the start of the Dose Optimization Phase, and abstain from taking these to the end of the Treatment Phase (Visit 17) or ET.
• Subject must have a score of ≥4 (Moderately Ill) on the clinician-administered Clinical Global Impressions-Severity (CGI-S) scale.
• Subject functions at an age-appropriate level intellectually, as determined by the Investigator.
• Subject must have age and sex adjusted ratings of ≥90th percentile Total Score on the ADHD-RS-IV (Preschool Version) rated over the past 6 months.
• Subject must have a systolic and diastolic blood pressure below the 95th percentile for age, and gender according to the 2017 AAP guidelines (Flynn 2017) based on the average of 3 measurements 2-5 minutes apart.
• Subject's parent/legal guardian and caregiver (if applicable) must understand and be willing and able to comply with all study procedures and visit schedule.
• Subject's parent/legal guardian, and caregiver (if applicable) must be able to speak and understand English or Spanish and be able to communicate satisfactorily with the Investigator and study coordinator.

Exclusion Criteria

• Subject with any clinically significant chronic medical condition that, in the judgment of the Investigator, may interfere with the participant's ability to participate in the study.
• Subject has any diagnosis of bipolar I or II disorder, major depressive disorder, conduct disorder, obsessive-compulsive disorder, any history of psychosis, autism spectrum disorder, disruptive mood dysregulation disorder (DMDD), intellectual disability, Tourette's Syndrome, confirmed genetic disorder with cognitive and/or behavioral disturbances.
• Subject has generalized anxiety disorder or panic disorder that has been the primary focus of treatment at any time during the 12 months prior to Screening, or that has required pharmacotherapy any time during the 6 months prior to Screening.
• Subject has evidence of any chronic disease of the central nervous system (CNS) such as tumors, inflammation, seizure disorder, vascular disorder, potential CNS related disorders that might occur in childhood (e.g., Duchenne Muscular dystrophy, myasthenia gravis, or other neurologic or serious neuromuscular disorders), or history of persistent neurological symptoms attributable to serious head injury.
• Subject taking anticonvulsants for seizure control currently or within the past 2 years before Screening are not eligible for study participation.
• Subject has