Efficacy of Esketamine Nasal Spray Plus Oral Antidepressant Treatment for Relapse Prevention in Patients With Treatment-Resistant Depression

Controlled studies have shown short-term efficacy of esketamine for treatment-resistant depression (TRD), but long-term effects remain to be established.

To assess the efficacy of esketamine nasal spray plus an oral antidepressant compared with an oral antidepressant plus placebo nasal spray in delaying relapse of depressive symptoms in patients with TRD in stable remission after an induction and optimization course of esketamine nasal spray plus an oral antidepressant. Design, Setting, and Participants: In this phase 3, multicenter, double-blind, randomized withdrawal study conducted from October 6, 2015, to February 15, 2018, at outpatient referral centers, 705 adults with prospectively confirmed TRD were enrolled; 455 entered the optimization phase and were treated with esketamine nasal spray (56 or 84 mg) plus an oral antidepressant. After 16 weeks of esketamine treatment, 297 who achieved stable remission or stable response entered the randomized withdrawal phase. Interventions: Patients who achieved stable remission and those who achieved stable response (without remission) were randomized 1:1 to continue esketamine nasal spray or discontinue esketamine treatment and switch to placebo nasal spray, with oral antidepressant treatment continued in each group. Main Outcomes and Measures: Time to relapse was examined in patients who achieved stable remission, as assessed using a weighted combination log-rank test.