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.
METHODS: This phase 3, open-label, multicenter, long-term (up to 1 year) study was conducted between October 2015 and October 2017. Patients (≥ 18 years) with TRD (DSM-5 diagnosis of major depressive disorder and nonresponse to ≥ 2 OAD treatments) were enrolled directly or transferred from a short-term study (patients aged ≥ 65 years). Esketamine nasal spray (28-mg, 56-mg, or 84-mg) plus new OAD was administered twice a week in a 4-week induction (IND) phase and weekly or every-other-week for patients who were responders and entered a 48-week optimization/maintenance (OP/MAINT) phase.
RESULTS: Of 802 enrolled patients, 86.2% were direct-entry and 13.8% were transferred-entry; 580 (74.5%) of 779 patients who entered the IND phase completed the phase, and 150 (24.9%) of 603 who entered the OP/MAINT phase completed the phase. Common treatment-emergent adverse events (TEAEs) were dizziness (32.9%), dissociation (27.6%), nausea (25.1%), and headache (24.9%). Seventy-six patients (9.5%) discontinued esketamine due to TEAEs. Fifty-five patients (6.9%) experienced serious TEAEs. Most TEAEs occurred on dosing days, were mild or moderate in severity, and resolved on the same day. Two deaths were reported; neither was considered related to esketamine. Cognitive performance generally either improved or remained stable postbaseline. There was no case of interstitial cystitis or respiratory depression. Treatment-emergent dissociative symptoms were transient and generally resolved within 1.5 hours postdose. Montgomery-Åsberg Depression Rating Scale total score decreased during the IND phase, and this reduction persisted during the OP/MAINT phase (mean [SD] change from baseline of respective phase to endpoint: IND, -16.4 [8.76]; OP/MAINT, 0.3 [8.12]).
CONCLUSIONS: Long-term esketamine nasal spray plus new OAD therapy had a manageable safety profile, and improvements in depression appeared to be sustained in patients with TRD.
TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02497287.