About one-third of patients with depression fail to achieve remission despite treatment with multiple antidepressants. This study compared the efficacy and safety of switching patients with treatment-resistant depression from an ineffective antidepressant to flexibly dosed esketamine nasal spray plus a newly initiated antidepressant or to a newly initiated antidepressant (active comparator) plus placebo nasal spray.Methods: This was a phase 3, double-blind, active-controlled, multicenter study conducted at 39 outpatient referral centers. The study enrolled adults with moderate to severe nonpsychotic depression and a history of nonresponse to at least two antidepressants in the current episode, with one antidepressant assessed prospectively. Confirmed nonresponders were randomly assigned to treatment with esketamine nasal spray (56 or 84 mg twice weekly) and an antidepressant or antidepressant and placebo nasal spray. The primary efficacy endpoint, change from baseline to day 28 in Montgomery-Åsberg Depression Rating Scale (MADRS) score, was assessed by a mixed-effects model using repeated measures. Results: Of 435 patients screened, 227 underwent randomization and 197 completed the 28-day double-blind treatment phase. Change in MADRS score with esketamine See related features: Commentary by Dr. Schatzberg (p. 422) and CME course (p. 491)

clinicaltrials.gov identifier: NCT01998958.

Twice-weekly and thrice-weekly administration of ketamine at 0.5 mg/kg similarly maintained antidepressant efficacy over 15 days.