Open-label Long-Term Safety and Efficacy of SPN-812 (Viloxazine Extended-release Capsule) in Adults With ADHD

*Please note, Inclusion/Exclusion Criterion "A" applies to subjects who completed Study 812P306 and enrolled in Study 812P311 on either the same day or up to 7 days after the end of Study 812P306. Inclusion/Exclusion Criterion "B" applies to subjects who completed Study 812P306, but enrolled in study 812P311 greater than 7 days after the end of study 812P306*

Inclusion Criteria "A"

• Is a male or female who completed Study 812P306 and opts/consents to participate in the study if approved by PI.
• Continues to be medically healthy and with clinically normal laboratory profiles, vital signs, and electrocardiograms (ECGs), in the opinion of the Investigator, assessed at Visit 1.
• Is able to read and understand the Informed Consent Form (ICF).
• Has signed the ICF.
• Is willing and able to attend study appointments within specified time windows.
• Is a female of childbearing potential (FOCP) who is either sexually inactive (abstinent) or, if sexually active, agrees to use one of the following acceptable birth control methods beginning at least 30 days prior to the first dose of SM and throughout the study:
• Simultaneous use of male condom and intra-uterine contraceptive device placed at least 4 weeks prior to first SM administration
• Surgically sterile male partner
• Simultaneous use of male condom and diaphragm with spermicide
• Established hormonal contraceptive

Females are considered not to be of childbearing potential if they are either post-menopausal (amenorrhea for at least 2 years and serum follicle stimulating hormone [FSH] level of >40 IU/L) or permanently sterilized (e.g., bilateral tubal ligation, hysterectomy, bilateral oophorectomy for 6 months minimum prior to their Visit 1).

• Is a male who:
• Agrees to use 2 methods of contraception in combination if his female partner is of childbearing potential; this combination of contraceptive methods must be used from Visit 1 to ≥ 1 month after the last dose of SM, OR
• Has been surgically sterilized prior to Visit 1.

Exclusion Criteria "A"

• Is currently participating in another clinical trial other than Study 812P306.
• Has any current psychiatric disorder per Diagnostic and Statistical Manual of Mental Disorders - 5th Edition (DSM-5) criteria other than ADHD with the following exceptions: ADHD is primary diagnosis with comorbidity/secondary diagnoses of major depression disorder (MDD), nicotine dependence, social anxiety disorder, generalized anxiety disorder, or phobias.
• Current diagnosis of significant systemic disease and/or of a major psychiatric or neurological disorder, including history or family history of seizures or seizure-like disorders.
• Current evidence of suicidality (suicidal thoughts or behaviors).
• Female subjects who are pregnant, lactating and/or sexually active and not agreeing to use one of the acceptable birth control methods throughout the study.
• Has a positive result on urine drug screen at Visit 1.
• Use of prohibited concomitant medications including known CYP1A2 substrates (e.g., theophylline, melatonin) at the Visit 1 for the duration of the study.
• Has a clinical laboratory value, vital sign value or ECG result at Visit 1 that is considered to be clinically significant in the opinion of the Investigator.
• Has one or more clinical laboratory test values outside the reference range at Visit 1 that, in the opinion of the Investigator, are clinically significant, or any of the following (see Note below):
• Serum creatinine > 1.5 times the upper limit of normal (ULN);
• Serum total bilirubin > 1.5 times ULN;
• Serum alanine aminotransferase or aspartate aminotransferase > 2 times ULN.
• Has any of the following cardiology findings at Visit 1 (see Note below):
• Abnormal ECG that is, in the Investigator's opinion, clinically significant;
• PR interval > 220 ms;
• QRS interval > 130 ms;
• QTcF interval > 450 ms (for men) or > 470 ms (for women) (QT corrected using Fridericia's method);
• Second- or third-d