Evaluation of SPN-812 (Viloxazine Extended-release Capsule) High Dose in Adolescents With ADHD

This study will evaluate the efficacy and safety of high doses of SPN-812 in adolescents (12-17 years old) with ADHD

This is a multicenter, randomized, double-blind, placebo-controlled, 3-arm, parallel-group study to assess the efficacy and safety of SPN-812 as a monotherapy for the treatment of adolescents 12-17 years old with ADHD.

Eligibility Criteria:
Inclusion Criteria:

1. Healthy male or female subjects, 12-17 years of age, inclusive.
2. Diagnosis of ADHD according to the Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5), confirmed with the Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID).
3. Attention Deficit/Hyperactivity Disorder Rating Scale-5, Home Version: Adolescent, Investigator Administered and Scored (ADHD-RS-5) score of at least 28.
4. CGI-S score of at least 4 at screening.
5. Weight of at least 35 kg.
6. Free of medication for the treatment of ADHD for at least one week prior to randomization and agreement to remain so throughout the study.
7. Considered medically healthy by the Investigator via assessment of physical examination, medical history, clinical laboratory tests, vital signs, and electrocardiogram.
8. Written informed consent obtained from the subject's parent or legal representative and informed assent from the subject, if applicable.
9. Females of childbearing potential (FOCP) must be either sexually inactive (abstinent) or, if sexually active, must agree to use one of the following acceptable birth control methods beginning 30 days prior to the first dose, throughout the study:

   1. simultaneous use of male condom and intra-uterine contraceptive device placed at least four weeks prior to the first study drug administration
   2. surgically sterile male partner
   3. simultaneous use of male condom and diaphragm with spermicide
   4. established hormonal contraceptive

Exclusion Criteria:

1. Current diagnosis of major psychiatric disorders. Subjects with Major Depressive Disorder are allowed in the study if the subject is free of episodes both currently and for the last six months.
2. Current diagnosis of major neurological disorders. Subjects with seizures or a history of seizure disorder within the immediate family (siblings, parents), or a history of seizure-like events are excluded from the study.
3. Current diagnosis of significant systemic disease.
4. Evidence of suicidality (defined as either active suicidal plan/intent or active suicidal thoughts, or more than one lifetime suicide attempt) within the six months before Screening or at Screening.
5. BMI greater than 95th percentile for the appropriate age and gender.
6. History of an allergic reaction to viloxazine or related drugs.
7. Any food allergy, intolerance, restriction or special diet that, in the opinion of the Investigator, could contraindicate the subject's participation in this study.
8. Subjects who received any investigational drug within the longer of 30 days or 5 half-lives prior to Day 1 dosing of SM.
9. Any reason, which, in the opinion of the Investigator, would prevent the subject from participating in the study.
10. Positive drug screen at the Screening Visit. A positive test for amphetamines is allowed for subjects receiving a stimulant ADHD medication at Screening; the subject will be required to discontinue the stimulant for the study, beginning at least one week prior to the Baseline Visit.
11. Pregnancy or refusal to practice abstinence or acceptable birth control during the study (for female subjects of childbearing potential)