A Study to Evaluate the Safety and Efficacy of Intranasal Esketamine in Treatment-resistant Depression

The purpose of this study is to assess the efficacy and dose response of intranasal esketamine (Panel A: 28 mg, 56 mg, and 84 mg and Panel B: 14 mg and 56 mg) compared with placebo in improving depressive symptoms in participants with treatment-resistant depression (TRD).

This will be a 2-panel, randomized ( participants are assigned different treatments based on chance), double-blind (neither investigator nor participant knows which treatment the participant receives), placebo-controlled (placebo is an inactive substance that is compared with a drug to test whether the drug has a real effect in a clinical trial), multicenter study. Approximately 100 male and female adult participants diagnosed with TRD will participate in this study. For participants in both panels (Panel A and Panel B), there will be 4 study phases: a 4-week screening phase, a double-blind treatment phase (Day 1 to Day 15), an optional open-label treatment phase (Panel A: Day 15 to 74; Panel B: Day 15 to 25), and an 8-week post-treatment (follow-up) phase. Depending on the treatment Panel, patients will be assigned to intranasal placebo or intranasal esketamine 14 mg, 28 mg, 56 mg, or 84 mg. Safety assessments will be performed throughout the study. The maximum study duration for a participant will be 23 weeks for Panel A and 16 weeks for Panel B.

Eligibility Criteria:
Inclusion Criteria:

--Participant must meet Diagnostic and Statistical Manual of Mental Disorders -Fourth Edition -Text Revised (DSM-IV-TR) diagnostic criteria for Major Depressive Disorder (MDD), without psychotic features, based upon clinical assessment, and confirmed by the Mini International Neuropsychiatric Interview (MINI)-Participant's major depressive episode and treatment response must be deemed "valid" by remote independent raters-Participant must have had an inadequate response to at least 2 antidepressants, at least one of which is in the current episode of depression; the antidepressant treatment response questionnaire (ATRQ) will be used to assess antidepressant treatment response during the current episode; prior medication history will be used to determine antidepressant treatment response in prior episode(s) -Have an Inventory of Depressive Symptoms-Clinician rated, 30-item (IDS-C30) total score \>=34 at Screening and predose at Day 1

Exclusion Criteria:

-Participant has a current DSM-IV-TR diagnosis of bipolar and related disorders, intellectual disability, or cluster b personality disorder (e.g., borderline personality disorder, antisocial personality disorder, histrionic personality disorder, and narcissistic personality disorder) -Participant has a current or prior DSM-IV-TR diagnosis of a psychotic disorder, MDD with psychosis, post-traumatic stress disorder (PTSD), or obsessive compulsive disorder (OCD) -Anatomical or medical conditions that may impede delivery or absorption of study medication (e.g., undergone facial reconstruction, rhinoplasty, significant structural or functional abnormalities of the nose or upper airway; obstructions or mucosal lesions of the nostrils or nasal passages; undergone sinus surgery in the previous 2 years; signs and symptoms of rhinitis) -Has an abnormal or deviated nasal septum with any 1 or more of the following symptoms: blockage of 1 or both nostrils, nasal congestion (especially 1-sided), frequent nosebleeds, frequent sinus infections, and at times has facial pain, headaches, and postnasal drip -Has a history of substance abuse (drug or alcohol) or dependence (except nicotine or caffeine) within the previous 1 year of the screening visit -Participant has known allergies, hypersensitivity, intolerance, or contraindication to esketamine/ketamine or its excipients