Objective: To evaluate the long-term safety and efficacy of intranasal esketamine in patients with treatment-resistant depression from the Asian subgroup of the SUSTAIN-2 study. Methods: SUSTAIN-2 was a phase 3, open-label, single-arm, multicenter study comprising a 4-week screening, 4-week induction, 48-week optimization/maintenance, and 4-week follow-up (upon esketamine discontinuation) phase. Patients with treatment-resistant depression received esketamine plus an oral antidepressant during the treatment period. Results: The incidence of ≥ 1 serious treatment-emergent adverse event (TEAE) among the 78 subjects from the Asian subgroup (Taiwan: 33, Korea: 26, Malaysia: 19) was 11.5% (n = 9); with no fatal TEAE. 13 Asian patients (16.7%) discontinued esketamine due to TEAEs. The most common TEAEs were dizziness (37.2%), nausea (29.5%), dissociation (28.2%), and headache (21.8%). Most TEAEs were mild to moderate in severity, transient and resolved on the same day. Upon discontinuation of esketamine, no trend in withdrawal symptoms was observed to associate long-term use of esketamine with withdrawal syndrome. There were no reports of drug seeking, abuse, or overdose. Improvements in symptoms, functioning and quality of life, occurred during in the induction phase and were generally maintained through the optimization/maintenance phases of the study. Conclusion: The safety and efficacy of esketamine in the Asian subgroup was generally consistent with the total SUSTAIN-2 population. There was no new safety signal and no indication of a high potential for abuse with the long-term (up to one year) use of esketamine in the Asian subgroup. Most of the benefits of esketamine occurred early during the induction phase.

Purpose This Phase 3, multicenter study (NCT03434041) was conducted in primarily Chinese patients with treatment-resistant depression (TRD) to support the registration of esketamine nasal spray in China. Patients and Methods This randomized, double-blind, active-controlled study was conducted in China and the United States (US) in patients with TRD (single or recurrent episode). Eligible patients were randomized 1:1 to receive intranasal esketamine or matching placebo, each in conjunction with a newly initiated oral antidepressant (AD; duloxetine, escitalopram, sertraline, and venlafaxine extended release) (ie, esketamine plus AD or AD plus placebo). The primary endpoint, change from baseline in Montgomery-Åsberg Depression Rating Scale (MADRS) total score at Day 28, was analyzed using a mixed-effects model for repeated measures. Secondary endpoints including safety were also evaluated. Results Of 252 randomized patients (China, 224; US, 28), 214 completed the double-blind treatment phase. The difference between treatment groups at Day 28 was not statistically significant (difference in least-square means [95% CI]: −2.0 [−4.64, 0.55]; 2-sided p = 0.123). However, esketamine plus AD demonstrated a clinically meaningful treatment difference compared with AD plus placebo in MADRS total score at 24 hours after first dose for the study overall population and China sub-population (difference in least-square mean [95% CI]: −3.3 [−5.33, −1.33] and −2.6 [−4.64, −0.60], respectively). No new safety signals were observed. Conclusion Esketamine plus AD was not statistically superior to AD plus placebo in improving depressive symptoms in TRD patients at Day 28. Rapid reduction in depressive symptoms within 24 hours was observed for TRD patients treated with esketamine plus AD in the overall population and China sub-population. Safety was consistent with the established safety profile of esketamine.