Safety and Efficacy Study of Centanafadine Sustained-Release (CTN SR) in Adults With Attention-Deficit Hyperactivity Disorder (ADHD)

Inclusion Criteria

• Participant was 18 to 60 years of age, inclusive, at the time of consent.
• Participant meets Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for a primary diagnosis of ADHD, defined as, established by a comprehensive psychiatric evaluation based on DSM-5 criteria with at least 5 of the 9 subtype criteria met, as determined by the Conners' Adult ADHD Diagnostic Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-4). Note: DSM-5 was used for screening / diagnosis and DSM-4 was used for evaluation throughout the study.
• Participant had a Baseline score of greater than or equal to 28 using the Attention-Deficit Hyperactivity Disorder Rating Scale IV (ADHD-RS-IV).
• Participant had a minimum score of 4 on the Clinical Global Impression of Severity at Baseline.
• Participant was functioning at an age-appropriate level intellectually, as judged by the Investigator.

Exclusion Criteria

• Participant had a current comorbid psychiatric disorder that was either controlled with medications prohibited in this study or was uncontrolled and associated with significant symptoms. Exclusionary conditions included any severe comorbid Axis II disorder or severe Axis I disorder (such as post-traumatic stress disorder, psychosis, bipolar illness, severe obsessive compulsive disorder, severe depressive or severe anxiety disorder) or other symptomatic manifestations that, in the opinion of the examining physician, would have contraindicated CTN SR treatment or confound efficacy or safety assessments. Specifically, participants with mild to moderate forms of Axis I disorders (for example, social phobia and dysthymia) may have been included, whereas participants with a lifetime history of psychosis or bipolar disorder were excluded. Comorbid psychiatric diagnosis was established by a Semi-Structured Clinical Interview for DSM-5 Axis I Disorders (the Mini lnternational Neuropsychiatric lnterview, Version 6.0 [M.I.N.I. 6.0]).
• Participants who were currently considered a suicide risk, any participant who had previously made a suicide attempt, or those who were currently demonstrating active suicidal ideation as measured by the Columbia-Suicide Severity Rating Scale (C-SSRS) at Screening, or if in the opinion of the investigator the participant was considered a suicide risk. Participants who developed suicidal ideation or behavior during the study as measured by the C-SSRS were discontinued and followed appropriately.
• The participant had a body mass index of less than 18.5 or greater than or equal to 40 at Baseline.
• Participant had a concurrent chronic or acute illness (such as severe allergic rhinitis or an infectious process requiring antibiotics), disability, or other condition that might have confounded the results of safety assessments administered in the study or that might have increased risk to the participant.
• Participant had a history of seizures (other than infantile febrile seizures), any tic disorder (except transient tic disorder and participant had no episodes greater than or equal to 1 year), or a current diagnosis and/or a known family history of Tourette's Disorder (that is, first degree relatives).
• Participant had a known history of symptomatic cardiovascular disease, advanced arteriosclerosis, structural cardiac abnormality, cardiomyopathy, serious heart rhythm abnormalities, coronary artery disease, transient ischemic attack or stroke or other serious cardiac problems that may have placed them at increased vulnerability to potential sympathomimetic effects.
• Participant had a known family history of sudden cardiac death or ventricular arrhythmia.
• Participant had a history of significant bleeding or coagulation disorder and/or low platelet levels (less than 130 x 10^9/liter) or increased international normalized ratio (greater than 1.3) at Screening.
• Participant had a history of cancer (other than noncomplic