A Study of the Efficacy of Intravenous Esketamine in Adult Patients With Treatment-Resistant Depression

This is a double-blind (neither physician nor patient knows the treatment that the patient receives), double-randomization (the study drug is assigned by chance), 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), multiple dose titration study in adult patients with treatment resistant depression (TRD). The study will assess the efficacy of esketamine at 24 hours after dosing on Day 1, administered as a 0.40 mg/kg and 0.20 mg/kg intravenous (i.v.) infusion, compared with placebo in improving symptoms of depression in patients with TRD, using the Montgomery-Asberg Depression Rating Scale (MADRS). The study will consist of 3 phases: a screening phase of up to 2 weeks, a 7-day double-blind treatment phase (Day 1 to Day 7), and a 4-week posttreatment (follow up) phase. The interval between the first and last dose of study medication is 3 days. The total study duration for each patient will be a maximum of 7 weeks.