Study to Evaluate the Efficacy and Safety of 3 Fixed Doses of Intranasal Esketamine in Addition to Comprehensive Standard of Care for the Rapid Reduction of the Symptoms of Major Depressive Disorder, Including Suicidal Ideation, in Pediatric Participants Assessed to be at Imminent Risk for Suicide

This study will enroll participants with major depressive disorder (MDD) presenting with
suicidal ideation who are assessed to be at imminent risk for suicide. The study will be
conducted in 4 phases: a screening evaluation performed within 48 hours prior to Day 1
intranasal dose; a 25-day double-blind treatment phase (Days 1-25); an 8‑week initial
post-treatment phase (Days 25-81); and a subsequent phase to complete a full 6‑month
post-treatment follow-up (Days 81-200). Efficacy, safety, pharmacokinetic, biomarker, and
pharmacogenomic evaluations will be performed in the study at defined schedule. The duration
of the participant's participation will be approximately 29 weeks. If you or a loved one are
having thoughts of suicide, please seek immediate medical help. Go to the emergency room or
call the National Suicide Prevention Lifeline at 1-800-273-8255.

Inclusion Criteria:

- Participants must meet diagnostic and statistical manual of mental disorders (5th
edition) {DSM-5} diagnostic criteria for major depressive disorder (MDD), without
psychotic features, based upon clinical assessment and confirmed by the mini
international neuropsychiatric interview for children and adolescents (MINI KID)

- Participant must have a children's depression rating scale-revised (CDRS-R) total
score of equal or more than (>=) 58 predose on Day 1

- As part of standard of care treatment, participant must agree to be hospitalized
voluntarily for a recommended period of 5 days after randomization (may be shorter or
longer if clinically warranted in the investigator's opinion)

- As part of the newly initiated or optimized standard of care treatment, participant
must agree to take one of the prescribed non-investigational antidepressant
medications (fluoxetine, escitalopram, sertraline) at least during the double-blind
treatment phase (Day 25)

- As part of standard of care treatment, participant must agree to participate in a
specific psychological intervention (individual cognitive behavioral therapy [CBT],
interpersonal therapy, family therapy or psychodynamic psychotherapy) at least through
the initial 8-week post-treatment follow-up period (Day 81)

Exclusion Criteria:

- Participants has a current DSM-5 diagnosis of bipolar (or related disorders),
intellectual disability, autism spectrum disorder, conduct disorder, anorexia nervosa,
oppositional defiant disorder, or obsessive compulsive disorder

- Participants currently meets DSM-5 criteria for borderline personality disorder.
Participants not meeting full DSM-5 criteria for borderline personality disorder but
exhibiting recurrent suicidal gestures, threats, or self-mutilating behaviors should
also be excluded

- Participant has a current or prior DSM-5 diagnosis of a psychotic disorder or MDD with
psychosis

- Participant meets the DSM-5 severity criteria for moderate or severe substance or
alcohol use disorder (except for nicotine or caffeine) within the 6 months before
screening. A history (lifetime) of ketamine, phencyclidine (PCP), lysergic acid
diethylamide (LSD), or 3, 4-methylenedioxy-methamphetamine (MDMA) hallucinogen-related
use disorder is exclusionary

- Participant has a history of seizure disorder