IPC Research


  • A 2-week follow-up phase: The intranasal study medication is no longer given, but the oral antidepressant medication may be continued if clinically appropriate. 

  • Continue intranasal esketamine and the same oral antidepressant, OR

This randomized, double-blind, active-controlled, multicenter trial will assess the efficacy of intranasal esketamine plus an oral antidepressant compared with an oral antidepressant (active comparator) plus intranasal placebo in delaying relapse of depressive symptoms in participants with treatment-resistant depression (TRD) who are in stable remission after an induction and optimization course of intranasal esketamine plus an oral antidepressant. The study consists of 5 phases:

  • A 4-week open-label induction phase: Intranasal esketamine twice weekly plus an oral antidepressant (duloxetine, escitalopram, sertraline, or venlafaxine XR)

  • Does not have a history of moderate or severe substance or alcohol use disorder​

  • A 4-to-7 week screening and observational phase.

  • Meets DSM-5 diagnostic criteria for single-episode MDD (if single-episode MDD, the duration must be ≥2 years) or recurrent MDD, without psychotic features, based upon clinical assessment and confirmed by MINI​

Treatment-resistant Depression

  • Non-response to at least 2, but no more than 5, oral antidepressant treatments in current episode of depression and currently taking an antidepressant with non-response​

  • A 12-week optimization/maintenance phase: Weekly treatment sessions of intranasal esketamine for the first 4 weeks with continued oral antidepressant. After the first 4 weeks, the frequency of intranasal treatment sessions will be adjusted based on the severity of depressive symptoms.


  • Male or female 18-64 years of age​

  • Does not have a psychotic disorder, bipolar or related disorders, comorbid obsessive compulsive disorder, or intellectual disability​

  • Does not have uncontrolled hypertension​

  • A double blind maintenance phase of variable duration: Random assignment to either:

For additional information, call Anne at IPC Research, 262-513-0700.

Additional criteria will apply during the screening phase to determine eligibility.​

A Study of Intranasal Esketamine Plus an Oral Antidepressant for Relapse Prevention in Adult Participants with Treatment-resistant Depression (SUSTAIN-1)

  • Moderate to Severe depression​

  • Continue with the same oral antidepressant, but switch to intranasal placebo.