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 signatureof informed consent, and there must be documentation of assent (as applicable) by theparticipant.
• Participant must meet Diagnostic and Statistical Manual of Mental Disorders, FifthEdition (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 andagree to comply with any applicable contraceptive requirements..
• Participant has an ADHD-RS-5 Child, Home Version Total Score of greater than or equalto (>=) 28 and Clinical Global Impression - Severity of Illness (CGI-S) score >=4 atbaseline (Visit 2). Participant is currently not on ADHD therapy, or is not completelysatisfied with their current ADHD therapy.

Exclusion Criteria:

• Participant is required or anticipated to take medications that have central nervoussystem effects or affect performance. Stable use of bronchodilator inhalers is notexclusionary.
• Participant has a concurrent chronic or acute illness, disability, or other conditionthat might confound the results of safety assessments conducted in the study or thatmight increase risk to the participant. - Participant has a documented allergy,hypersensitivity, or intolerance to amphetamine or to any excipients in theinvestigational product.
• Participant has failed to fully respond, based on investigator judgment, to anadequate course of amphetamine therapy.
• Participant has a known family history of sudden cardiac death or ventriculararrhythmia.
• Participant has a blood pressure measurement >=95th percentile for age, sex, andheight at screening (Visit 1) and/or baseline (Visit 2).
• Participant has a height less than or equal to (<=) 5th percentile for age and sex atscreening (Visit 1) or baseline (Visit 2).
• Participant has a weight <=5th percentile for age and sex at screening (Visit 1) orbaseline (Visit 2).
• Participant has a known history of symptomatic cardiovascular disease, structuralcardiac abnormality, cardiomyopathy, serious heart rhythm abnormalities, or otherserious cardiac conditions placing them at increased vulnerability to thesympathomimetic 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 atthe screening (Visit 1) or baseline visit (Visit 2).
• Participant has current abnormal thyroid function, defined as abnormalthyroid-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 currentlydemonstrating suicidal ideation.