An Efficacy and Safety Study w/ Azstarys® in Children With ADHD

Inclusion Criteria:

1. In Cohort 1, subjects must be at least 4 years old and less than 5 years and 10months at Screening; in Cohort 2, subjects must be at least 6 years old and lessthan 12 years and 10 months at Screening.

2. Subjects must have a body weight within the 5th and 95th percentile according to thegender-specific weight-for-age percentile charts from the Centers for DiseaseControl and Prevention (CDC). See calculator at https://www.infantchart.com/child/.

3. Female subjects must agree, if they are of childbearing potential at Screening orwhen they become of childbearing potential during the study, to remain abstinent oragree to use an effective and medically acceptable form of birth control from thetime of written or verbal assent to at least 14 days after the last dose of studydrug. Childbearing potential is defined as follows: Girls under the age of 12 whohave not had their first period will be considered "not of child-bearing potential."Girls 12 years of age (including girls who will become 13 years during the study)will be considered "of child-bearing potential," even if they have not yet had theirfirst period. Irrespective of age, girls who have had their first period, will beconsidered "of child-bearing potential."

4. Subjects must be in general good health defined as the absence of any clinicallyrelevant abnormalities as determined by the Investigator based on physicalexaminations, vital signs, electrocardiograms (ECGs), medical history, and clinicallaboratory values (chemistry, hematology, urinalysis) at Screening. If any of thechemistry or hematology tests are not within the laboratory's reference range, thenthe subject can be included only if the Investigator determines the deviations to benot clinically relevant.

5. At least one parent/legal guardian of the subject must voluntarily give writtenpermission for him/her to participate in the study.

6. Subjects in Cohort 2 must give written or verbal assent prior to studyparticipation. For verbal assent, the procedure will be documented and signed by awitness. A parent or guardian may not be the witness for a child's verbal assentdocument.

7. Subject must meet Diagnostic and Statistical Manual of Mental Disorders - FifthEdition (DSM-5) criteria for a primary diagnosis of ADHD (combined, inattentive, orhyperactive/impulsive presentation) per clinical evaluation and confirmed byMini-International Neuropsychiatric Interview for Children and Adolescents (MINIKid).

8. Subject has had ADHD symptoms present for at least 6 months prior to the ScreeningVisit.

9. 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 TreatmentPeriod, and abstain from taking these to the end of Visit 6 or ET; and wash outnon-stimulant ADHD medications from 14 days prior to the start of the TreatmentPeriod, and abstain from taking these to the end of Visit 6.

10. Subject must have a score of ≥4 (Moderately Ill) on the clinician-administeredClinical Global Impressions-Severity (CGI-S) scale. For subjects requiring washoutof ADHD medications, this criterion refers to a score following washout.

11. Subjects must have age and sex adjusted ratings of ≥90th percentile Total Score onthe ADHD-Rating Scale (ADHD-RS) rated over the past 6 months (for 4- and 5-year oldchildren, use Preschool Version of ADHD-RS-IV; for 6-12 years old children, useADHD-RS-5).

12. Subject functions at an age-appropriate level intellectually, as determined by theInvestigator.

13. Subject must have a systolic and diastolic blood pressure below the 95th percentilefor age and gender according to the 2017 AAP guidelines (Flynn 2017) based on theaverage of 3 measurements 2-5 minutes apart.

14. Subject, subject's parent/legal guardian, and caregiver (if applicable) mustunderstand and be willing and able to comply with all study procedures and visitschedule.

15. Subject, parent/legal guardian, and caregiver (if applicable) must be able to speakand understand English or Spanish and be able to communicate satisfactorily with theInvestigator and study coordinator.

Exclusion Criteria:

1. If female, must not be pregnant or breastfeeding, and if of childbearing potential,must have a negative urine pregnancy test at the start of the Screening Period. Inaddition, a positive pregnancy test before the last dose of study drug will resultin early termination from the study.

2. Subject with any clinically significant chronic medical condition that, in thejudgment of the Investigator, may interfere with the participant's ability toparticipate in the study.

3. Subject has any diagnosis of bipolar I or II disorder, major depressive disorder,conduct disorder, obsessive-compulsive disorder, any history of psychosis, autismspectrum disorder, disruptive mood dysregulation disorder (DMDD), intellectualdisability, Tourette's Syndrome, confirmed genetic disorder with cognitive and/orbehavioral disturbances. Subjects with oppositional defiant disorder (ODD) arepermitted to enroll in the study as long as ODD is not the primary focus oftreatment, and, in the opinion of the Investigator, the ODD is mild to moderate, andeligible subjects with ODD are appropriate and cooperative during Screening.

4. Subject has generalized anxiety disorder or panic disorder that has been the primaryfocus of treatment at any time during the 12 months prior to Screening or that hasrequired pharmacotherapy any time during the 6 months prior to Screening.

5. Subject has evidence of any chronic disease of the central nervous system (CNS) suchas tumors, inflammation, seizure disorder, depression, vascular disorder, potentialCNS-related disorders that might occur in childhood (e.g., Duchenne Musculardystrophy, myasthenia gravis, or other neurologic or serious neuromusculardisorders), or history of persistent neurological symptoms attributable to serioushead injury.

6. Subject taking anticonvulsants for seizure control or antidepressants currently orwithin the past 2 years before Screening are not eligible for study participation. Apast history of febrile seizure or drug-induced seizure is allowed.

7. Subject has a current (last month) psychiatric diagnosis other than specific phobia,motor skills disorders, ODD, sleep disorders, elimination disorders, adjustmentdisorders, learning disorders, or communication disorders. Subjects allowed toenroll with any of these DSM disorders will require written justification from theInvestigator documenting why the conditions will not interfere with participationand to emphasize that ADHD is the primary indication.

8. In the opinion of the Investigator, subject has clinically significant suicidalideation/behavior, based on history of attempted suicide and the Columbia-SuicideSeverity Rating Scale (C-SSRS) assessment at Screening.

9. Subject has any clinically significant unstable medical abnormality, chronic disease (including asthma or diabetes), or a history of a clinically significant abnormalityof the cardiovascular (including cardiomyopathy, serious arrhythmias, structuralcardiac disorders, or severe hypertension), gastrointestinal, respiratory, hepatic,or renal systems, or a disorder or history of a condition (e.g., malabsorption,gastrointestinal surgery) that may interfere with absorption, distribution,metabolism, or excretion of study drug. In cases in which the impact of thecondition upon risk to the subject or study results is unclear, the medical monitorshould be consulted. Any subject with a known cardiovascular disease or condition (even if controlled) must be discussed with the Medical Monitor during Screening.

10. Subject has a history or presence of abnormal ECGs, which in the Investigator'sopinion is clinically significant.

11. Subject has a history of, or currently has, a malignancy.

12. Subject has uncontrolled thyroid disorder as evidenced by thyroid stimulatinghormone (TSH) ≤0.8 x the lower limit of normal (LLN) or ≥1.25 x the upper limit ofnormal (ULN) for the reference laboratory at Screening.

13. Subject has greater than trace proteinuria in the urinalysis at Screening. Subjectswith greater than trace proteinuria in the urinalysis at Screening but with a urineprotein to creatinine (UP/C) ratio <0.2 in a first morning void urine sample willnot be excluded from enrollment.

14. Subjects has a current or recent (past 12 months) history of drug abuse; or currentor recent history of drug abuse in someone living in the subject's home, or areusing or planning to use prohibited drugs during the trial as specified in theprotocol.

15. Subject has a positive urine drug screen at Screening. Subjects with a positivemethylphenidate (MPH) urine drug screen may be allowed to continue in the study,provided that the Investigator determines that the positive test is a result oftaking prescribed medications and subject is willing to wash out the currentmedication as required.

16. Subject has participated in any other clinical study with an investigationaldrug/product within 30 days or at least 5 half-lives, whichever is longer, prior toScreening.

17. Subject has taken ADHD medications from more than one class within 30 days prior toScreening. Subjects on a stable dose of one ADHD medication with occasional use ofADHD medications from another class are eligible at the discretion of theInvestigator.

18. Subjects with demonstrated lack of response or intolerability to adequate dose andduration of treatment with MPH products. Judgment of adequate dose and duration isat the discretion of the Investigator.

19. Subject has a positive urine MPH screen by dipstick (e.g., NarcoCheck®) at Visit 2.

20. Subject is planning to initiate psychotherapy during the study (subjectsparticipating in psychotherapy beginning at least 4 weeks before study initiationare permitted to continue).

21. Subject has a history of severe allergies or adverse drug reactions to more than oneclass of medications.

22. Subject has a history of allergic reaction or a known or suspected sensitivity toMPH or any substance that is contained in the study drug.

23. Subject, parent/legal guardian, and caregiver (if applicable, at the Investigator'sdiscretion) has commitments during the study that would interfere with attendingstudy visits.

24. Subject or subject's family anticipates a move outside the geographic range of theinvestigative site during the study period, or plans extended travel inconsistentwith the recommended visit interval during study duration.

25. Subject has one or more siblings living in the same household who are enrolled inthis or another clinical drug trial.

26. Subject shows evidence of current physical, sexual, or emotional abuse.

27. Subject is, in the opinion of the Investigator, unsuitable in any other way toparticipate in this study.