Adult Attention Deficit Hyperactivity Disorder (ADHD) Study With Amphetamine Sulfate

Inclusion Criteria:

1. Is male or female between 18 and 55 years of age, inclusive, at the time ofScreening.

2. Meets criteria for diagnosis of ADHD using Conners' Adult ADHD Diagnostic Interviewfor Diagnostic and Statistical Manual of Mental Disorders (DSM-IV™) adapted forDSM-5™ (CAADID), including onset of ADHD symptoms before the age of 12.

3. Has an AISRS total score of ≥26 at Visit 2.

4. Has a clinician-administered Clinical Global Impression-Severity (CGI-S) score of 4or greater at Visit 2.

5. In the clinical judgment of the Investigator, the subject needs pharmacologicaltreatment for ADHD.

6. Must read and write English at a level sufficient to provide written informedconsent and to complete study-related materials.

7. For subjects currently on a stable dose of allowed non-ADHD medication, there willbe no expected changes in subject's medications during the study with the exceptionof medications listed in Section 5.9.2.

8. Males and females who are fertile and sexually active with a partner of the oppositesex must adhere to contraception requirements for the duration of the study asfollows:

• Females of childbearing potential must agree to be abstinent or to use highlyeffective forms of contraception.

• Females of non-childbearing potential, defined as surgically sterile (statuspost hysterectomy, bilateral oophorectomy, or bilateral tubal ligation) orpost-menopausal for at least 12 months do not require contraception during thestudy.

• Males , with female partners of childbearing potential must agree to beabstinent or use a medically acceptable form of contraception from screeningthrough the end of study.

Exclusion Criteria:

1. Has a primary psychiatric diagnosis other than ADHD.

2. Has any other current secondary or co-morbid medical, psychiatric, or socialcondition which, in the opinion of the investigator, might compromise subjectsafety, or is likely to interfere with protocol compliance or to confound theassessment of safety or efficacy.

3. Has a history or current symptoms of bipolar disorder, schizophrenia, or psychoticdisorder.

4. Has clinically significant cognitive impairment in the clinical judgment of theInvestigator.

5. Has a Body Mass Index (BMI) of <17 or ≥39 kg/m2.

6. Has a Screening or Baseline triplicate-average blood pressure of ≥139 millimeter ofmercury (mmHg) systolic or ≥89 mmHg diastolic. Blood pressure will be taken intriplicate, and the average will be used for evaluating entry criteria.

7. Is pregnant or breastfeeding, or is planning to become pregnant during the study.

8. Has a history of any of the following disorders:

• Seizure disorder (excluding a history of isolated febrile seizures <6 yearsold),

• Inadequately or not treated hypertension is defined as a subject who has bloodpressure indicative of Stage 2 hypertension (systolic pressure ≥140 mmHg ordiastolic pressure ≥90 mmHg). Subjects who are adequately treated must be on astable dose of antihypertensive medications for 3 months prior to screening andtheir antihypertensive medications are not anticipated to change.

• Untreated thyroid disease. Subjects with a history of thyroid disease who havebeen on a stable dose of thyroid hormone for at least three months are eligibleto participate if their thyroid-stimulating hormone (TSH) does not fall in theexcluded range, shown below in 14.

• Glaucoma

• Tourette's disorder, or chronic tics.

• Subjects who have had gastrointestinal surgery or a procedure that involves:

• Excision or partial excision of the esophagus, stomach, small and largeintestine, liver, pancreas or biliary tree. Appendectomy, cholecystectomyand/or removal of gallstones in the bile ducts (as long as the ductsremain intact) are exceptions.

• Reduction of the stomach volume without excision or partial excision ofthe stomach (e.g. restrictive surgery/procedure)

• Obesity treatments that can affect gastrointestinal (GI) capacity orfunction, such as electrical stimulation systems, gastric balloon systems,and gastric external drainage systems

9. Has Electrocardiogram (ECG) or clinical evidence of the following:

• Fridericia's corrected QT wave interval (QTcF) > 470 milliseconds (msec) forfemales, and > 450 msec for males

• Atrial or ventricular hypertrophy

• Intraventricular conduction defects other than incomplete right bundle branchblock in the absence of other heart disease

• Myocardial infarct, ischemia, or symptomatic coronary artery disease within 1year prior to the Screening Visit

• Clinically significant atrial or ventricular dysrhythmia; the heart must be inpredominantly normal sinus rhythm

• Second or third degree atrioventricular block

• Heart failure

• Functionally significant cardiac structural abnormality or valvular disease

• Cardiomyopathy

• Any other cardiovascular condition that the Investigator feels may predisposethe subject to cardiovascular events (e.g. myocardial infarction, stroke) orarrhythmia

10. Known family history of sudden cardiac death in the absence of pre-existing heartdisease.

11. Use of any psychotropic medication within 28 days of the Baseline visit except forADHD medication. (Sedative hypnotics prescribed as a sleep aid at a stable dose forat least 28 days prior to Baseline, at bedtime only, are allowed during the study.)

12. Has used prohibited drugs or agents within 28 days of the Baseline visit throughStudy Visit 7. (Stimulant medications are allowed until 7 days before the Baselinevisit.) Non-stimulant ADHD medications (guanfacine, bupropion, clonidine, and/oratomoxetine) are not allowed within 28 days of Visit 2 or at any time during thestudy. Note: Medications that are being taken for psychiatric or medical disordersother than ADHD should not be discontinued for the purpose of qualifying for studyparticipation unless the medication is deemed medically unnecessary by theprescribing physician.

13. Has received an investigational drug within 60 days of the Screening visit.

14. Has an abnormal laboratory test value, vital sign, or other exam finding atScreening or Baseline that, in the opinion of the Investigator, warrants exclusionfrom the study. In addition, subjects with laboratory values listed below areconsidered exclusionary:

• Serum aspartate transaminase (AST) or alanine transaminase (ALT) >1.5 × upperlimit of normal (ULN)

• Serum total bilirubin >1.5 × ULN unless due to Gilbert's Syndrome

• Serum creatinine >1.3 × ULN

• Glycosylated hemoglobin (HbA1c) ≥7.0%.

• TSH <0.9 × lower limit of normal (LLN) or TSH >1.2 × ULN

15. Reports a history of hypersensitivity or intolerance to any formulation ofamphetamine.

16. Reports a history of poor therapeutic response to any formulation of amphetamine ormethylphenidate despite a clearly adequate trial (including dose and duration).

17. Is unable to swallow medication in capsule form.

18. Is unable or unwilling to follow directions of study staff or comply with all thetesting and requirements of the protocol.

19. Has a positive urine drug result at Screening (with the exception of current ADHDstimulant therapy, if any). Note: subjects should be informed that they should notparticipate in the trial or submit to urine drug testing if they are using anycontrolled or recreational drug (other than a prescribed stimulant for ADHD), andnon-use should be confirmed prior to testing.

20. Has a positive blood alcohol level at Screening. Note: subjects should be informedthat alcohol consumed within 12 hours of screening may result in a positive test.

21. Has current or known history of drug or alcohol abuse within the past 12 months.

22. Has a history of human immunodeficiency virus (HIV), hepatitis B, or untreatedhepatitis C infection. Note: subjects with a history of hepatitis C infection whohave been treated and whose hepatitis C virus ribonucleic acid (HCV RNA) iscurrently undetectable are not excluded.

23. In the past 12 months, has had an intensity of suicidal ideation of greater than 1orany self-injurious behavior using the Columbia Suicide Severity Rating Scale at theScreening or Baseline visits.