In adults with treatment-resistant depression who had not responded to at least two prior oral antidepressants, esketamine nasal spray taken alone (without an oral antidepressant) reduced depressive symptoms more than a placebo. Over four weeks, both a 56 mg and an 84 mg dose of esketamine produced significantly greater improvements on the Montgomery-Åsberg Depression Rating Scale than placebo, with effects apparent as early as 24 hours after the first dose. Common side effects included nausea, dissociation, dizziness, and headache. The findings suggest that esketamine monotherapy could offer a new treatment option for patients who cannot tolerate or do not respond to oral antidepressants.
For patients with treatment-resistant depression who did not show a response within the first week of treatment, a full four-week induction course of esketamine nasal spray plus an oral antidepressant may still provide benefit. In a pooled analysis of two phase 3 trials, among those not meeting early response criteria at day 2 or days 2 and 8, the odds of a response by day 28 were about 1.6 times higher with esketamine plus antidepressant compared to antidepressant plus placebo. The findings suggest that lack of early improvement does not preclude later benefit from the full induction course.
A post hoc analysis of two pooled 4-week phase 3 trials examined predictors of response and remission in patients with treatment-resistant depression receiving esketamine nasal spray plus a new oral antidepressant compared to a new oral antidepressant plus placebo nasal spray. Younger age, being employed, having fewer failed antidepressants in the current episode, and early reduction in Clinical Global Impression-Severity score at day 8 predicted better outcomes. Those on esketamine had 68% higher odds of response and 55% higher odds of remission. In the esketamine group, response was more likely in employed patients, those without baseline anxiety, and those with early symptom improvement.
Adding cognitive behavioral therapy to esketamine treatment reduces suicidal ideation more than esketamine alone in people with major depression and suicidal thoughts. In a randomized trial of 93 patients, 72% completed the study, meeting feasibility goals. Those who received 16 weeks of CBT plus esketamine showed greater improvement on three measures of suicidal ideation than those receiving esketamine with usual care: a mean difference of -1.91 on the Beck Scale for Suicidal Ideation, -0.33 on the Clinician Global Improvement Scale for Suicide Severity, and -3.77 on the depression rating scale. No difference was found on the Columbia-Suicide Severity Rating Scale or in suicide-related events.