Safety, Tolerability, and Pharmacokinetics of Multiple Rising Doses of TAK-137 in Adults With Attention-Deficit/Hyperactivity Disorder

The drug being tested in this study is called TAK-137. TAK-137 is being tested to find a
safe and well-tolerated dose and to assess how TAK-137 is metabolized in people with
attention-deficit/ hyperactivity disorder (ADHD). This study will look at side effects and
lab results in people who take TAK-137. This study is designed as a randomized,
sequential-cohort, multiple rising dose study.

Therefore, the TAK-137 2 mg Cohort will not start until the TAK-137 0.5 mg Cohort has
completed, etc.

This trial will be conducted in the United States. The overall time to participate in this
study is up to 42 days. Participants will make at least 2 visits to the clinic, including
one 9-day period of confinement to the clinic. All participants will be contacted by
telephone 7 days after the last dose of study drug for a follow-up assessment.

Inclusion Criteria:

1. Is a male or female adult who is 18 to 55 years of age, inclusive.

2. Weighs at least 45 kg and has a body mass index (BMI) between 18 and 30.0 kg/m^2,
inclusive at Screening.

3. Has a documented diagnosis of attention-deficit/hyperactivity disorder (ADHD) for a
minimum of 1 year.

4. Is willing to discontinue all medications to treat adult ADHD (eg, stimulants,
antidepressants) and all other medications and dietary products as specified in the
protocol, from Day -7 until Follow-up phone call (Day 14).

Exclusion Criteria:

1. Has received any investigational compound within 30 days prior to the first dose of
study medication.

2. Has uncontrolled, clinically significant neurologic (including mildly abnormal or
significantly abnormal EEG at screening), cardiovascular, pulmonary, hepatic, renal,
metabolic, gastrointestinal, urologic, immunologic, endocrine disease, or psychiatric
disorder (other than ADHD), or other abnormality, which may impact the ability of the
participant to participate or potentially confound the study results.

3. Has previously had a seizure or convulsion (lifetime), including absence seizure and
febrile convulsion.

4. Has a positive urine drug result for drugs of abuse other than amphetamines or other
medications to treat ADHD or positive result for alcohol at Screening or Check-in
(Day -1).

5. Has taken any excluded medication, supplements, or food products listed in the
Excluded Medications and Dietary Products.

6. Is pregnant or lactating or intending to become pregnant before, during, or within 12
weeks after participating in this study; or intending to donate ova during such time
period.

7. Has used nicotine-containing products (including but not limited to cigarettes,
pipes, cigars, chewing tobacco, nicotine patch or nicotine gum) within 28 days prior
to Check-in (Day -1).