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

This is a multicenter, open-label extension study aimed to assess long-term safety and efficacy of SPN-812 when administered alone or in conjunction with an Food and Drug Administration (FDA)-approved Attention-Deficit Hyperactivity Disorder (ADHD) medication in the treatment of ADHD in adult subjects who completed a blinded study of SPN-812 (812P306). Subjects initiate SPN-812 dosing at 200 mg/day once daily (QD) during first 2 weeks. At or after Visit 2 (Week 2), per the Investigator's discretion and based on Investigator's assessment of subject's clinical response and tolerability, the dose of SPN-812 can be titrated up or tapered down in increments of 50 mg/day, 100 mg/day, 150 mg/day, or 200 mg/day per week to a target dose within the ranges between 200 and 600 mg/day. Additionally, after 12 weeks of dosing (after Visit 4), at the discretion of the Investigator and based on subject's clinical response, the optimized dose of SPN-812 may be supplemented with an adjunctive FDA-approved stimulant treatment. Total treatment duration per subject from Visit 1 to Visit 22 (end of study) is approximately 3 years (156 weeks ± 1 week) or until SPN-812 becomes commercially available.