Evaluation of SPN-812 (Viloxazine Extended-release Capsule) in Adults With ADHD

Inclusion Criteria

• Is male or female, aged 18 to ≤ 65 years at screening.
• Is able to read and understand the Informed Consent Form (ICF).
• Written informed consent obtained from the subject (a signed ICF).
• Weight within the normal or overweight ranges according to accepted values of the Body Mass Index Chart (18.0 to 35 kg/m2).
• Is able to swallow capsules whole, without crushing, chewing or cutting.
• Is willing and able to attend study appointments within the specified time windows.
• Has a primary diagnosis of ADHD according to the DSM-5 classification, with diagnosis made at least 6 months prior to screening and confirmed with Structured Clinical Interview for DSM-5 Clinical Trials version (SCID-5-CT).
• Has an AISRS Adult ADHD (Attention-Deficit/Hyperactivity Disorder) Investigator Symptom Rating Scale total score of ≥ 26 at the Screening Visit and at the Baseline Visit (V2, Day 1).
• Has a CGI-S score of ≥ 4 (moderately ill or worse) at the Screening Visit (V1) and Baseline Visit (V2, Day 1).
• 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 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 screening).

• Males must:
• Use 2 methods of contraception in combination if his female partner is of childbearing potential; this combination of contraceptive methods must be used from the Baseline Visit to ≥ 1 month after the last dose of SM, or
• Have been surgically sterilized prior to the Screening Visit.

Exclusion Criteria

• Has previously enrolled in a SPN-812 study.
• Is currently participating in another clinical trial or has participated in a clinical trial within 60 days prior to the first Screening Visit.
• Is a member of the study personnel or of their immediate families, or is a subordinate (or immediate family member of a subordinate) to any of the study personnel.
• 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 history of severe drug allergy or hypersensitivity, or known hypersensitivity, to the study medication or excipients.
• Has history of moderate or severe head trauma or other neurological disorder or systemic medical disease that, in the Investigator's opinion, is likely to affect central nervous system functioning. This would include subjects with:
• A current diagnosis of a major neurological disorder; or
• Seizures, seizure disorder or seizure-like events; or a history of seizure disorder within the immediate family (siblings, parents); or
• Encephalopathy
• Has any history of schizophrenia, schizoaffective disorder, bipolar disorder, borderline personality disorder, antisocial personality disorder, narcissistic personality disorder, autism, post-traumatic stress disorder or obsessive-compulsive disorder.
• Has any current psychiatric disorder (per 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, and subject is not receiving pharmacological treatment for the comorbidity/secondary diagnoses (e.g., antidepressant for MDD) at ti