With the pharmacokinetics (PK) of centanafadine currently being evaluated in adults. The PK of extended-release centanafadine may differ in children compared to adults due to physiological differences in the gastrointestinal tract. The information in this trial will support pediatric dose selection in future trials.

Inclusion Criteria:

• Written informed consent obtained from a legally acceptable representative and assent obtained from the participant prior to the initiation of any trial-related procedures.
• Male or female participants 9 to 12 years of age, inclusive, at the time of informed consent.
• Participants with documented history of ADHD and confirmation of an ADHD prescription medication.
• Participant is judged by the investigator to be clinically stable and has not had any psychiatric hospitalizations within the past 12 weeks.

Exclusion Criteria:

• Participants with a history of intellectual disability as determined by at least 1 of the following: intelligence quotient (IQ) < 70, or clinical evidence, or a social or school history that is suggestive of an intellectual disability.

• Participants who have any of the following:

  • Significant risk of committing suicide based on history
  • Current suicidal behavior
  • Imminent risk of injury to self
  • Active suicidal ideation
  • Any lifetime history of suicidal behavior detected by the "Baseline/Screening" version of the Columbia-Suicide Severity Rating Scale (C-SSRS).

• Participants with a lifetime history of a substance use disorder (as determined by Diagnostic and Statistical Manual of Mental Disorders, 5th Edition [DSM-5] criteria), or current substance misuse including alcohol and benzodiazepines, but excluding caffeine and nicotine.

• Participants with hypothyroidism or hyperthyroidism or an abnormal result for free thyroxine (T4) at screening.

• Participants who currently have clinically significant neurological, dermatological, hepatic, renal, metabolic, hematological, immunological, cardiovascular, pulmonary, or gastrointestinal disorders.

• Participants with insulin-dependent diabetes mellitus.

• Participants with epilepsy or a history of seizures or a history of severe head trauma or cerebrovascular disease.

• Any major surgery within 30 days prior to dosing with the investigational medicinal product (IMP).

• Any history of significant bleeding or hemorrhagic tendencies.

• Blood transfusion within 30 days prior to dosing with IMP.

• Participants with a positive drug screen for cocaine, marijuana (even if by prescription), or other illicit drugs, or alcohol, are excluded and may not be retested or rescreened.

• Participants who have a supine or standing diastolic blood pressure, after resting for at least 5 minutes ≥ 95 mmHg.

• Participants who participated in a clinical trial and were exposed to IMP within the last 30 days prior to screening or who participated in more than 2 interventional clinical trials within the past year.

• Participants with a history of true allergic response to a medication or a history of dermatologic adverse reactions or anaphylaxis secondary to drug exposure.

• Participants who do not tolerate venipuncture or have poor venous access that would cause difficulty when collecting blood samples.

• Relatives of the trial site employees cannot participate in the trial.

Anonymized Individual participant data (IPD) that underlie the results of this study will be shared with researchers to achieve aims pre-specified in a methodologically sound research proposal. Small studies with less than 25 participants are excluded from data sharing.

Data will be available after marketing approval in global markets, or beginning 1-3 years following article publication. There is no end date to the availability of the data.

Otsuka will share data on an Otsuka-owned remotely accessible data sharing platform with Python and R analytical software. Research requests should be directed to clinicaltransparency@Otsuka-us.com