Vyvanse in Children Aged 6 to 12 Years

Inclusion Criteria:

• Children ages 6 to <12 years at study entry

• Severe obesity defined as BMI >/= 1.2 times the 95th percentile at the screeningvisit

• Prior failed attempt of lifestyle therapy per parent/guardian report

• Written informed consent of parent/legal guardian and written assent of participant

Exclusion Criteria:

• Contraindications to lisdexamfetamine, including current or recent (< 14 days) useof monoamine oxidase inhibitor and known hypersensitivity to amphetamine products

• Family history of sudden death or ventricular arrhythmia in any first or seconddegree relative with any of the following: sudden or unexplained death includingsudden infant death syndrome, cardiomyopathy, heart transplant, familial arrhythmia (such as Wolff-Parkinson-White syndrome, long QT interval, or implantabledefibrillator).

• Any history of fainting or seizure from exercise, startle, or fright

• Clinically significant congenital or structural heart disease or arrhythmia

• BMI <1.2 times the 95th percentile at the baseline/randomization visits

• Hypertension defined as systolic blood pressure (SBP) and/or diastolic bloodpressure (DBP) >/= 95th percentile (on 3 separate occasions) at the screening ORbaseline/randomization visits

• Tachycardia defined heart rate (HR) >/= 120 bpm (on 3 separate occasions) at thescreening OR baseline/randomization visits

• Current or recent (< 3 months) use of psychostimulant or sympathomimetic amine

• History of chemical dependency

• Diabetes mellitus (type 1 or 2)

• Current or recent (< 3 months) use of anti-obesity medication(s)

• Previous bariatric surgery

• Recent initiation or change in dose (< 3 months prior) of anti-hypertensive or lipidmedication(s)

• Thyroid stimulating hormone (TSH) > 1.5x upper limit of normal (ULN)

• Aspartate transaminase (AST) or alanine transaminase (ALT) > 3x ULN

• Fasting glucose >/= 126 mg/dL

• History of mania, schizophrenia, bipolar disorder, or psychosis

• Unstable depression or anxiety that has required hospitalization in the past 12months

• Any history of suicide attempt

• Columbia Suicide Severity Rating Scale (C-SSRS) with a score of Moderate or Hiogh atthe screening or baseline/randomization visits

• Children's Depressive Inventory 2 (CDE-2_ score >/= 70 (based on parent or childreport) at the screening or baseline/randomization visits

• Concomitant use of tricyclic antidepressants, selective serotonin re-uptakeinhibitors (SSRIs), serotonin and norepinephrine re-uptake inhibitors (SNRIs),lithium, fentanyl, tramadol, triptans, tryptophan, buspirone and St. John's wort atany time during the study

• Refusal to use adequate contraception (double barrier method or stable hormonalcontraception plus single barrier method, tubal ligation, or abstinence) in girls ofchildbearing potential

• Inability to swallow test capsule (participants will have two opportunities)