Safety and Tolerability Study of SPD489 in Preschool Children Aged 4-5 Years, Diagnosed With Attention-deficit/Hyperactivity Disorder

Inclusion Criteria:

1. Participant is male or female aged 4-5 years inclusive at the time of consent fromantecedent studies SPD489-211 or SPD489-347 or at the time of consent if directlyenrolled.
2. Before completing any study-related procedures, participant's parent(s) or legallyauthorized representative (LAR) must provide signature of informed consent, and theremust be documentation of assent (if applicable) by the participant indicating that theparticipant is aware of the investigational nature of the study. The participant'sparent(s) or LAR should understand that the required procedures and restrictions arebeing conducted in accordance with the International Council of Harmonisation (ICH)Good Clinical Practice (GCP) Guideline E6 (1996), any updates or revisions, andapplicable federal or local regulations.
3. Participant and parent(s)/LAR are willing and able to comply with all of the testingand requirements defined in the protocol, including oversight of morning dosing.Specifically, the parent/LAR should be available at approximately 7:00AM (+2 hours) todispense the dose of investigational product for the duration of the study.
4. Roll-over participant from antecedent SPD489-347 study: a. Participant completed the antecedent study (SPD489-347)
5. Direct enrolled participants must meet antecedent study inclusion criteria, as listedbelow
6. Participant must meet Diagnostic and Statistical Manual of Mental Disorders,Fourth Edition (DSM-IV-TR) criteria for a primary diagnosis of ADHD (any subtype)based on a detailed psychiatric evaluation conducted by a sponsor-approvedclinician
7. Participant has an attention-deficit/hyperactivity disorder rating scale- IV (ADHD-RS-IV) Preschool Version total score at the Baseline Visit (Visit 0) ofgreater than equals to (>=) 28 for boys and >= 24 for girls.
8. Participant has a Clinical Global Impressions - Severity of Illness (CGI-S) score >=4 at the Baseline Visit (Visit 0).
9. Participant has a Peabody Picture Vocabulary Test, Fourth Edition standard scoreof >=70 at the Screening Visit (Visit -1).
10. Participant has undergone an adequate course of non-pharmacological treatmentbased on investigator judgment or the participant has a severe enough conditionto consider enrollment without undergoing prior non-pharmacological treatment,based on investigator judgment.
11. Participant has, in the opinion of the investigator, participated in a structuredgroup activity (eg, preschool, sports, Sunday school) so as to assess symptomsand impairment in a setting outside the home.
12. Participant has lived with the same parent(s) or guardian for >=6 months.

Exclusion Criteria:

1. Participant was terminated from an antecedent SPD489 study for non-compliance and/orexperienced a serious adverse event (SAE) or adverse event (AE) resulting intermination.
2. Participant is required to or anticipates the need to take medications that havecentral nervous system effects or affect performance, such as, but not limited to,sedating antihistamines and decongestant sympathomimetics, or monoamine oxidaseinhibitors. Stable use of bronchodilator inhalers is not exclusionary.
3. Participant has a concurrent chronic or acute illness (such as, but not limited to,severe allergic rhinitis or an infectious process requiring antibiotics), disability,or other condition that might confound the results of safety assessments conducted inthe study or that might increase risk to the participant. Similarly, the participantwill be excluded if he or she has any additional condition(s) that, in theinvestigator's opinion, would prohibit the participant from completing the study orwould not be in the best interest of the participant. The additional condition(s)would include any significant illness or unstable medical condition that could lead todifficulty complying with the protocol. Mild, stable asthma is not exclusionary.
4. Participant has a documented allergy, hypersensitivity, or intolerance to amphetamineor to any excipients in the investigational product.
5. Participant has a known family history of sudden cardiac death or ventriculararrhythmia.
6. Participant has a blood pressure measurement >= 95th percentile for age, sex, andheight at the screening visit (Visit -1) or the baseline visit (Visit 0) or a historyof moderate or severe hypertension.
7. Participant has a known history of symptomatic cardiovascular disease, unexplainedsyncope, exertional chest pain, advanced arteriosclerosis, structural cardiacabnormality, cardiomyopathy, serious heart rhythm abnormalities, coronary arterydisease, or other serious cardiac problems placing them at increased vulnerability tothe sympathomimetic effects of a stimulant drug.
8. Participant is taking any medication that is excluded per the protocol.
9. Participant had any clinically significant electrocardiogram (ECG) or clinicallaboratory abnormalities at the Screening Visit (Visit -1) or baseline visit (Visit 0), based on investigator judgment.
10. Participant has a history of hyperthyroidism, or current abnormal thyroid function,defined as abnormal thyroid stimulating hormone (TSH) and thyroxine (T4) at theScreening Visit (Visit-1) or Visit 0. Treatment with a stable dose of thyroidmedication for at least 3 months is permitted.
11. Participant has taken another investigational product or has taken part in a clinicalstudy within 30 days prior to the Screening Visit (Visit -1).
12. Participant is well-controlled on his/her current ADHD medication with acceptabletolerability.
13. Participant has glaucoma.
14. Participant has failed to fully respond, based on investigator judgment, to anadequate course of amphetamine therapy.
15. Participant has a current, controlled (requiring medication or therapy) oruncontrolled, comorbid psychiatric disorder including but not limited to any of thebelow co-morbid Axis I disorders and Axis II disorders:
16. post-traumatic stress disorder (PTSD) or adjustment disorder
17. bipolar illness, psychosis, or family history of these disorders
18. pervasive developmental disorder
19. obsessive-compulsive disorder (OCD)
20. psychosis/schizophrenia
21. participant has a serious tic disorder, or a family history of Tourette'sdisorder
22. participant is currently considered a suicide risk in the opinion of theinvestigator, has previously made a suicide attempt, or has a prior history of,or is currently demonstrating active suicidal ideation. Participants withintermittent passive suicidal ideation are not necessarily excluded based on theassessment of the investigator
23. a history of physical, sexual, or emotional abuse
24. any other disorder or agitated state that in the opinion of the investigator,contraindicates SPD489 or lisdexamfetamine dimesylate treatment or confoundefficacy or safety assessments.
25. Participant has initiated behavioral therapy within 1 month of the baseline visit (Visit 0). Participant may not initiate behavioral therapy during the study.
26. Participant has a height <=5th percentile for age and sex at the screening visit (Visit -1).
27. Participant has a weight <=5th percentile for age and sex at the screening visit (Visit -1).
28. Participant lives with anyone who currently abuses stimulants or cocaine.
29. Participant has a history of seizures (other than infantile febrile seizures).