Safety and Tolerability Study of SHP465 in Children Aged 4 to 12 Years Diagnosed With Attention-deficit/Hyperactivity Disorder (ADHD)

Inclusion Criteria:

- Participant is male or female aged 4-12 years inclusive at the time of consent.

- Participant's parent or legally authorized representative (LAR) must provide signature
of informed consent, and there must be documentation of assent (as applicable) by the
participant.

- Participant must meet Diagnostic and Statistical Manual of Mental Disorders, Fifth
Edition (DSM-5) criteria for a primary diagnosis of ADHD (any subtype).

- Participant who is a female and of child-bearing potential must not be pregnant and
agree to comply with any applicable contraceptive requirements..

- Participant has an ADHD-RS-5 Child, Home Version Total Score of greater than or equal
to (>=) 28 and Clinical Global Impression - Severity of Illness (CGI-S) score >=4 at
baseline (Visit 2). Participant is currently not on ADHD therapy, or is not completely
satisfied with their current ADHD therapy.

Exclusion Criteria:

- Participant is required or anticipated to take medications that have central nervous
system effects or affect performance. Stable use of bronchodilator inhalers is not
exclusionary.

- Participant has a concurrent chronic or acute illness, disability, or other condition
that might confound the results of safety assessments conducted in the study or that
might increase risk to the participant. - Participant has a documented allergy,
hypersensitivity, or intolerance to amphetamine or to any excipients in the
investigational product.

- Participant has failed to fully respond, based on investigator judgment, to an
adequate course of amphetamine therapy.

- Participant has a known family history of sudden cardiac death or ventricular
arrhythmia.

- Participant has a blood pressure measurement >=95th percentile for age, sex, and
height at screening (Visit 1) and/or baseline (Visit 2).

- Participant has a height less than or equal to (<=) 5th percentile for age and sex at
screening (Visit 1) or baseline (Visit 2).

- Participant has a weight <=5th percentile for age and sex at screening (Visit 1) or
baseline (Visit 2).

- Participant has a known history of symptomatic cardiovascular disease, structural
cardiac abnormality, cardiomyopathy, serious heart rhythm abnormalities, or other
serious cardiac conditions placing them at increased vulnerability to the
sympathomimetic effects of a stimulant drug.

- Participant has a history of seizures (other than infantile febrile seizures).

- Participant is taking any medication that is excluded per the protocol.

- Participant had any clinically significant ECG or clinical laboratory abnormalities at
the screening (Visit 1) or baseline visit (Visit 2).

- Participant has current abnormal thyroid function, defined as abnormal
thyroid-stimulating hormone and thyroxine at the screening or baseline visit.
Treatment with a stable dose of thyroid medication for at least 3 months is permitted.

- Participant is currently considered a suicide risk in the opinion of the investigator,
has previously made a suicide attempt, or has a prior history of or currently
demonstrating suicidal ideation.