Efficacy and safety of fixed doses of intranasal Esketamine as an add-on therapy to Oral antidepressants in Japanese patients with treatment-resistant depression: a phase 2b randomized clinical study

Efficacy of intravenous ketamine and intranasal esketamine with dose escalation for Major depression: A systematic review and meta-analysis

OBJECTIVE

Intravenous (IV) racemic ketamine and intranasal (IN) esketamine have demonstrated rapid antidepressant effects in treatment-resistant depression (TRD). This systematic review aims to evaluate the efficacy and safety of ketamine and esketamine at various dosages for depression.

METHODS

We included randomized controlled trials (RCTs) with parallel group dose comparison of ketamine and esketamine for depression/TRD. Ovid Medline, Embase, PsycINFO, Scopus and Cochrane databases were searched. Standardized mean differences were calculated using Hedges'-g to complete random effects meta-analysis. The efficacy outcomes were changes in depression outcomes for IV ketamine and IN esketamine respectively. Safety was assessed by reported adverse effects.

RESULTS

A random effects meta-analysis of studies (n = 12) showed efficacy in reducing depression symptoms with IV ketamine (Hedges'g = 1.52 [0.98-2.22], Z = 4.23, p < 0.001) and IN esketamine (Hedges' g = 0.31 [0.18-0.44], Z = 4.53, P < 0.001) compared to control/placebo. Treatment response was observed at IV ketamine doses ≤0.2 mg/kg, >0.2-0.5 mg/kg and > 0.5 mg/kg. Higher IV ketamine doses (>0.5 mg/kg) did not lead to greater treatment response. Esketamine doses of 56-84 mg were superior to 28 mg dose.

LIMITATIONS

Overall quality of evidence was low and limited by small number of studies. Publication bias was high.

CONCLUSIONS

This meta-analysis suggests that IV ketamine may be efficacious at doses as low as 0.2 mg/kg, with increasing dose response at 0.5 mg/kg, without demonstrable increased benefit at 1 mg/kg, based on a small number of studies. Efficacy for IN esketamine increases with doses above 28 mg with best response being found between 56 and 84 mg for reducing depressive symptoms.

Number needed to treat (NNT) for ketamine and esketamine in adults with treatment-resistant depression: A systematic review and meta-analysis

BACKGROUND

Ketamine has been established as efficacious in adults living with Treatment-resistant Depression (TRD). Toward providing a quantifiable estimate of the clinical meaningfulness of the therapeutic benefit of ketamine, herein, we conduct a systematic review that aims to report the Number Needed to Treat (NNT) and the Number Needed to Harm (NNH).

METHODS

This systematic review searched Embase, Medline/Pubmed, PsycINFO and ClinicalTrials.gov from inception up to October 15th 2023, for placebo-controlled, Randomized Controlled Trials (RCTs) assessing racemic ketamine or esketamine therapy for unipolar TRD. We calculated NNT and NNH for ketamine treatments over various time points.

RESULTS

A total of 21 studies with 2042 participants were included. Racemic ketamine treatments had pooled NNTs for response of 7 at 4 h, 3 from one day to one week and 9 for studies at four weeks. Esketamine treatment was found to have a similar efficacy with an NNT of 2 at one day and 11 at four weeks. NNH values indicated low risk for ketamine treatments.

LIMITATIONS

Limitations in the data used include the possibility of functional unblinding and selective reporting bias. Moreover, the meta-analysis may have been limited in its precision by including low threshold definitions of treatment resistance (≥ 1 failed antidepressant) and low-dose ketamine treatments.

CONCLUSION

Herein, we determined that the NNT for ketamine treatment in adults living with TRD across different intervals of observation was <10. We conclude that the NNTs observed herein are highly clinically meaningful in this difficult to treat disorder.

Hype or hope? High placebo response in major depression treatment with ketamine and esketamine: a systematic review and meta-analysis

Background

Ketamine and esketamine offer a novel approach in the pharmacological treatment of major depressive disorder (MDD). This meta-analysis aimed to investigate the placebo response in double-blind, randomized controlled studies (RCTs) on patients with MDD receiving ketamine or esketamine.

Methods

For this systematic review and meta-analysis Medline (PubMed), Cochrane Central Register of Controlled Trials (CENTRAL), PsycInfo and Embase databases were systematically searched for citations published up to March 17, 2023. A total number of 5017 abstracts was identified. Quality of the included trials was assessed with the Cochrane risk-of-bias tool. The meta-analysis was performed using a restricted maximum likelihood model. This study is registered with PROSPERO, number CRD42022377591.

Results

A total number of 14 studies and 1100 participants (593 in the medication group and 507 in the placebo group) meeting the inclusion criteria were selected. We estimated the pooled effect sizes of the overall placebo (d pl = -1.85 [CI 95%: -2.9 to -0.79] and overall treatment (dtr = -2.57; [CI 95% -3.36 to -1.78]) response. The overall placebo response accounts for up to 72% of the overall treatment response. Furthermore, we performed subgroup analysis of 8 studies for the for the 7 days post-intervention timepoint. Seven days post-intervention the placebo response (d pl 7d = -1.98 [CI 95%: -3.26 to -0.69]) accounts for 66% of the treatment response (d tr 7d = - 3.01 [CI 95%, -4.28 to -1.74]).

Conclusion

Ketamine and esketamine show large antidepressant effects. However, our findings suggest that the placebo response plays a significant role in the antidepressant response and should be used for the benefit of the patients in clinical practice.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022377591.

A systematic review and meta-analysis of the efficacy of ketamine and esketamine on suicidal ideation in treatment-resistant depression

PURPOSE

To systematically assess the evidence of efficacy and safety of the use of ketamine and esketamine for patients with treatment-resistant depression (TRD) with suicidal ideation (SI).

METHODS

We independently searched for clinical trials from inception to January 2023 using electronic databases, e.g., PubMed and EMBASE. A systematic review and meta-analysis were performed to assess SI scores of depression rating scales, which were regarded as the outcomes.

RESULTS

A total of five independent double-blind, placebo controlled randomized clinical trials (RCTs) are eligible for inclusion. Four of the studies used ketamine as an intervention and one used esketamine as an intervention. Three hundred ninety-one patients with TRD were included (the intervention group with ketamine or esketamine is 246, and the control group is 145). No statistically significant interaction between the subscales of suicide ideation (SMD = - 0.66, 95% CI (- 1.61, 0.29); Z = 1.36, P = 0.17) and antidepressant effects (SMD = - 0.99, 95% CI (- 2.33, 0.34); Z = 1.46, P = 0.15) based on the results of ketamine and esketamine, compared with placebo groups.

CONCLUSION

This meta-analysis suggested that esketamine and ketamine have failed to reduce suicidal ideation in patients with TRD. Further studies are desirable to confirm the effects of ketamine and esketamine in TRD patients.

Comparative efficacy, tolerability and acceptability of intravenous racemic ketamine with intranasal esketamine, aripiprazole and lithium as augmentative treatments for treatment-resistant unipolar depression: A systematic review and network meta-analysis

BACKGROUND

Intravenous racemic ketamine is a promising treatment for treatment-resistant depression. However, its clinical utility compared with intranasal esketamine and the other well-studied conventional pharmacological interventions (i.e., aripiprazole and lithium) as augmentative treatments for treatment-resistant unipolar depression in adults remains unclear. Therefore, we aimed to compare the efficacy, tolerability and acceptability of intravenous racemic ketamine with intranasal esketamine, aripiprazole and lithium under such conditions.

METHODS

The Cochrane Library, PubMed, CINHAL and ClinicalTrials.gov databases were systematically searched from their inception to 10 May 2023. Randomised controlled trials evaluating these drugs were included. A random-effects network meta-analysis was also performed.

RESULTS

In the primary analysis, all four drugs were significantly more effective than placebo. In addition, intravenous racemic ketamine was significantly more effective and acceptable than intranasal esketamine and aripiprazole. Intravenous racemic ketamine was not significantly different from placebo in tolerability, whereas intranasal esketamine and aripiprazole were significantly less tolerable than placebo. Lithium did not differ significantly from intravenous racemic ketamine in efficacy, tolerability and acceptability.

LIMITATIONS

The sample size of patients treated with intravenous racemic ketamine was small.

CONCLUSIONS

Intravenous racemic ketamine may be a better augmentative treatment for treatment-resistant unipolar depression than intranasal esketamine and aripiprazole. Whether intravenous racemic ketamine or lithium is superior is unclear currently. A larger head-to-head trial of intravenous racemic ketamine versus conventional augmentative treatments for treatment-resistant unipolar depression is needed.

The Efficacy and Safety of Intranasal Formulations of Ketamine and Esketamine for the Treatment of Major Depressive Disorder: A Systematic Review

Ketamine and its enantiomers represent an innovative glutamatergic agent as a treatment for individuals with treatment-resistant depression (TRD) and major depressive disorder (MDD) with suicidal ideation and behavior. Intranasal (IN) formulations could allow for quick onset of action on depressive symptoms as well as a reduction in side effects by bypassing the blood-brain barrier compared with administration via the intravenous route. The aim of this review was to provide an up-to-date analysis of the data on the efficacy and safety of IN ketamine and IN esketamine for the treatment of MDD. A systematic review following PRISMA guidelines was conducted. Databases (PubMed, Embase, MEDLINE, PsycINFO, and Google Scholar) were searched to capture articles about IN ketamine or IN esketamine for MDD. This systematic review highlighted the interest in IN routes of ketamine and esketamine for MDD patients with TRD or active suicidal ideation. They provide a rapid onset of antidepressant action within the first hours after administration. Nevertheless, the evidence of efficacy is stronger for IN esketamine than for IN ketamine in MDD patients. The safety profile appears to be acceptable for IN esketamine but requires further studies, and a more accurate IN delivery device is required for ketamine.

What clinicians need to know about intranasal esketamine for treatment-resistant depression?

OBJECTIVE

To review the usefulness of esketamine for treatment-resistant depression.

METHOD

Pivotal trials of intranasal esketamine in treatment-resistant depression were synthesized as a narrative review.

RESULTS

Esketamine is postulated to act through antagonism of N-methyl-D-aspartate (NMDA) glutamate receptors, but opioidergic effects may also be involved. Unlike intravenous ketamine, esketamine is given intranasally (under clinical observation), usually in addition to an oral antidepressant. Trials compared esketamine plus antidepressant versus placebo plus antidepressant. At 4 weeks, remission was 37% higher with esketamine/antidepressant than placebo/antidepressant. Speed of response and improvement in suicidality were comparable. In stable remitters on esketamine/antidepressant, 45% relapsed when esketamine was withdrawn over the following 6 months (whereas 25% relapsed on esketamine/antidepressant). Response appears less likely in patients with multiple antidepressant failures. Adverse effects include dissociation, dizziness, nausea, sedation, and headache but no psychosis. Hypertension affected 13%, especially older patients. Dose frequency is twice-weekly for 4 weeks, then weekly/fortnightly thereafter. No abuse has been reported. Unsubsidised cost may be beyond the reach of many Australians.

CONCLUSION

Intranasal esketamine plus antidepressant has been approved by regulators as moderately effective and acceptably tolerable for treatment-resistant depression. Cost is a drawback. Use often needs to be long-term and vigilance for abuse is essential.

Esketamine vs Midazolam in Boosting the Efficacy of Oral Antidepressants for Major Depressive Disorder: A Pilot Randomized Clinical Trial

Importance

Loss of a previously effective response while still using adequate antidepressant treatment occurs in a relatively high proportion of patients with major depressive disorder (MDD); therefore, there is a need to develop novel effective treatment strategies.

Objective

To assess the efficacy and safety of a single subanesthetic dose of esketamine in boosting the efficacy of oral antidepressants for treating fluctuating antidepressant response in MDD.

Design, Setting, and Participants

This single-center, double-blind, midazolam-controlled pilot randomized clinical trial was conducted at Beijing Anding Hospital, Capital Medical University in China. The study enrolled participants aged 18 years and older with fluctuating antidepressant response, defined as patients with MDD experiencing fluctuating symptoms after symptom relief and stabilization. Patient recruitment was conducted from August 2021 to January 2022, and participants were followed-up for 6 weeks. Data were analyzed as intention-to-treat from July to September 2022.

Interventions

All participants in the esketamine-treated group received intravenous esketamine at 0.2 mg/kg in 40 minutes. Participants in the midazolam control group received intravenous midazolam at 0.045 mg/kg in 40 minutes.

Main Outcomes and Measures

The primary outcome was the response rate at 2 weeks, defined as a 50% reduction in Montgomery-Åsberg Depression Rating Scale (MADRS). Secondary outcomes included response rate at 6 weeks, remission rates at 2 and 6 weeks, and change in MADRS and Clinical Global Impression-Severity score from baseline to 6 weeks; remission was defined by a MADRS score of 10 or lower.

Results

A total of 30 patients (median [IQR] age, 28.0 [24.0-40.0] years; 17 [56.7%] female) were randomized, including 15 patients randomized to midazolam and 15 patients randomized to esketamine; 29 patients completed the study. Response rates at 2 weeks were significantly higher in the esketamine-treated group than in the midazolam control group (10 patients [66.7%] vs 1 patient [6.7%]; P < .001). Participants treated with esketamine experienced significantly greater reduction in MADRS score from baseline to 2 weeks compared with those treated with midazolam (mean [SD] reduction, 15.7 [1.5] vs 3.1 [1.3]; P < .001). No serious adverse events were observed in this trial, and no psychotogenic effects and clinically significant manic symptoms were reported.

Conclusions and Relevance

This pilot randomized clinical trial found that a single subanesthetic dose of esketamine could boost the efficacy of oral antidepressants in treating fluctuating antidepressant response, with a good safety profile.

Trial Registration

Chinese Clinical Trial Registry Identifier: ChiCTR2100050335.

Efficacy and Safety of Esketamine Nasal Spray in Patients with Treatment-Resistant Depression Who Completed a Second Induction Period: Analysis of the Ongoing SUSTAIN-3 Study

BACKGROUND

Treatment-resistant depression (TRD) is a chronic illness requiring long-term treatment. Esketamine nasal spray (ESK) has been studied in several long-term trials of patients with TRD, including SUSTAIN-1 (NCT02493868) and SUSTAIN-3 (NCT02782104). This subgroup analysis of SUSTAIN-3 evaluated patients with TRD who received a second induction (IND) and maintenance treatment with ESK plus oral antidepressant (AD) after a relapse in SUSTAIN-1.

METHODS

Patients aged 18-64 years who achieved stable remission or response with ESK and subsequently relapsed after randomization to continue ESK or switch to placebo nasal spray (PBO) in SUSTAIN-1 and entered the IND phase of SUSTAIN-3 were included in this interim analysis. Response (≥50% improvement in total score from baseline for Montgomery-Åsberg Depression Rating Scale [MADRS] and Patient Health Questionnaire 9-item [PHQ-9]), remission (MADRS score ≤12; PHQ-9 total score <5), changes in depression rating scores (measured as mean change from baseline), and safety were evaluated (incidence of treatment-emergent and serious adverse events [AE]).

RESULTS

Of the 96 eligible patients who entered IND in SUSTAIN-3, 32 (33.3%) were taking ESK+AD at the time of relapse in SUSTAIN-1 and 64 (66.7%) were taking AD+PBO. Substantial improvements in depressive symptoms were observed over the second IND phase in both groups and were maintained over the optimization/maintenance (OP/M) phase. MADRS response rates following a second IND were 71.9% and 73.4% for previously relapsed (PR) ESK+AD and PR-AD+PBO, respectively; remission rates were 62.5% and 60.9%, respectively. During the IND and OP/M phases, 58.3% and 83.3% of patients experienced a treatment-emergent AE, respectively. No patients discontinued due to an AE during the second IND.

CONCLUSIONS

Patients with TRD benefitted from receiving a second IND and maintenance treatment with ESK and no new safety signals were identified.

Ketamine for the treatment of major depression: a systematic review and meta-analysis

Background

Intranasal esketamine has received regulatory approvals for the treatment of depression. Recently a large trial of repeated dose racemic ketamine also demonstrated efficacy in severe depression. However, uncertainties remain regarding comparative efficacy, dosage, and the time course of response.

Methods

In this systematic review and meta-analysis, we searched Embase, Medline, Pubmed, PsycINFO, and CENTRAL up to April 13, 2023, for randomised controlled trials (RCTs) investigating ketamine for depression. Two investigators independently assessed study eligibility and risk of bias and extracted the data on depression severity scores, response and remission rates, and all-cause dropouts. Multivariable mixed-effects meta-regressions incorporated drug formulation (racemic (Rac) or esketamine (Esket)) and dose (Low or High) as covariates. Treatment effects were assessed: immediately following the first dose, during further repeated dosing, and follow-up after the final dose of a treatment course. This study is registered with PROSPERO (CRD42021221157).

Findings

The systematic review identified 687 articles, of which 49 RCTs were eligible for analysis, comprising 3299 participants. Standardised mean differences (95% confidence intervals) immediately following the first/single treatment were moderate-high for all conditions (Rac-High: -0.73, -0.91 to -0.56; Esket-High: -0.48, -0.75 to -0.20; Rac-Low: -0.33, -0.54 to -0.12; Esket-Low: -0.55, -0.87 to -0.24). Ongoing effects during repeated dosing were significantly greater than the control for Rac-High (-0.61; -1.02 to -0.20) and Rac-Low (-0.55, -1.09 to -0.00), but not Esket-Low (-0.15, -0.49 to 0.19) or Esket-High (-0.22, -0.54 to 0.10). At follow-up effects remained significant for racemic ketamine (-0.65; -1.23 to -0.07) but not esketamine (-0.33; -0.96 to 0.31). All-cause dropout was similar between experiment and control conditions for both formulations combined (Odds Ratio = 1.18, 0.85-1.64). Overall heterogeneity varied from 5.7% to 87.6.

Interpretation

Our findings suggested that effect sizes for depression severity, as well as response and remission rates, were numerically greater for racemic ketamine than esketamine. Higher doses were more effective than low doses. Differences were evident in initial effects, ongoing treatment, and lasting effects after the final dose.

Funding

None.

Reporting of harms in clinical trials of esketamine in depression: a systematic review

While previous systematic reviews of trials evaluating conventional antidepressants highlighted inadequacies and inconsistencies in adverse event (AE) reporting, no evaluation is available on esketamine in resistant depression. The objective of this review was to assess quality of reporting AEs in all published clinical trials studying esketamine. It also aimed to compare the proportions of AEs reported in journal articles to those recorded in the ClinicalTrial.gov Registers. Clinical trials evaluating the efficacy and safety of esketamine in depression were searched using Medline and ClinicalTrials.gov. The quality of reporting harms was assessed using a 21-item checklist from the CONSORT Extension of Harms (1 point by item). The total quality score was graded into four categories: high (17-21), moderate (12-16), low (7-11) and very low (0-6). Ten clinical trials were included in the analysis. Nine trials were classified as 'low quality' with regard to safety, one trial was classified as 'moderate quality'. Compared to AEs recorded in ClinicalTrials.gov, we found that 41.5% of serious AEs and 39% of non-serious AEs were not reported in the published articles. Among them, the majority were psychiatric events but also cardiovascular events and 94% concerned patients from esketamine groups. Quality of AEs reporting in published clinical trials of esketamine was poor and harms were reported less frequently in journal publications than in ClinicalTrial.gov Registers. The study suggests that an assessment of the benefits/risks balance of esketamine based on the results reported in trial publications is flawed due to the poor accuracy and completeness of harm data.

The use of esketamine in the treatment of patients with oral antidepressant-resistant depression: systematic review and meta-analysis

The Guidelines Project, an initiative of the Brazilian Medical Association, aims to combine information from the medical field to standardize how to conduct, and to assist in the reasoning and decision-making of doctors. The information provided by this project must be critically evaluated by the physician responsible for the conduct that will be adopted, depending on the conditions and the clinical condition of each patient. Guideline conclusion: April 2023. Societies: Brazilian Medical Association.

Safety and tolerability of intramuscular and sublingual ketamine for psychiatric treatment in the Roots To Thrive ketamine-assisted therapy program: a retrospective chart review

Background

In the last few years, ketamine is becoming increasingly common in the treatment of mental health conditions, but there is a lack of safety data informing intramuscular and sublingual dosing in a community-focused group psychotherapy setting. The Roots To Thrive ketamine-assisted therapy (RTT-KaT) program is a unique 12-week RTT-KaT program with 12 community of practice (a form of group therapy) sessions and three ketamine medicine sessions.

Objectives

This study reports on adverse effects of intramuscular and sublingual ketamine dosing in a community group psychotherapy setting among 128 participants across four cohorts.

Design

Retrospective chart review.

Methods

A chart review of the RTT-KaT Program was performed retrospectively on four cohorts (n = 128) that participated in 448 sessions running between September 2020 and December 2021. Baseline characteristics and adverse events were captured including medication administration before, during, and after RTT-KaT sessions. Analyses by session and by individual were conducted. Chi-square test with Yates' continuity correction was used to assess side effects in subgroups from ketamine administration.

Results

RTT-KaT was well tolerated with none of the 128 participants dropping out of the program. Primarily, of the 448 sessions, 49.16% had elevated blood pressures post-KaT session by session. In terms of other adverse effects, 12.05% of participant-sessions experienced nausea, 2.52% had an episode of vomiting, 3.35% had a headache, and seven participant-sessions experienced dizziness. Analysis by individual revealed congruent findings.

Conclusion

These findings suggest good safety and tolerability for RTT-KaT among individuals seeking treatment for mental health issues. The majority of participants did not experience adverse reactions and the adverse events that were recorded involved transient symptoms that were resolved with rest and/or medications. The group therapy model described provides a comprehensive approach and presents a promising model for operating a KaT program in a community setting.

The antidepressant actions of ketamine and its enantiomers

Ketamine, an N-methyl-d-aspartate receptor (NMDAR) antagonist first developed as an anesthetic, has shown significant promise as a medication with rapid antidepressant properties in treatment-resistant depression. However, concerns such as adverse side effects and potential misuse liability have limited its widespread use. Racemic ketamine has two enantiomers-(S)- and (R)-ketamine-that appear to have disparate underlying mechanisms. This brief review summarizes some of the most recent preclinical and clinical research regarding the convergent and divergent prophylactic, immediate, and sustained antidepressant effects of (S)- and (R)-ketamine while addressing potential differences in their side effect and misuse liability profiles. Preclinical research suggests divergent mechanisms underlying (S)- and (R)-ketamine, with (S)-ketamine more directly affecting mechanistic target of rapamycin complex 1 (mTORC1) signaling and (R)-ketamine more directly affecting extracellular signal-related kinase (ERK) signaling. Clinical research suggests that (R)-ketamine has a milder side effect profile than (S)-ketamine and decreases depression rating scale scores, but recent randomized, controlled trials found that it had no significant antidepressant efficacy compared to placebo, suggesting that caution is warranted in interpreting its therapeutic potential. Future preclinical and clinical research is needed to maximize the efficacy of each enantiomer, either by optimizing dose, route of administration, or administration paradigm.

The therapeutic role of ketamine and esketamine in treating psychopathological domains of depression

Over the past two decades, ketamine has emerged as a novel effective and rapid-acting antidepressant. While the vast majority of studies on ketamine have focused on its ability to reduce the severity of depression broadly, its effectiveness in specific domains such as cognition, anhedonia, suicidality, and workplace/social/scholastic functionality has been neglected. Similarly, current treatments (e.g., SSRIs and SNRIs) aim to improve overall depression severity, which often results in the persistence of one or more residual symptom domains and prevents full recovery to premorbid functionality. In this review, we narratively synthesize the literature pertaining to the effectiveness of ketamine in treating key domains of depressive symptomatology (i.e., cognition, anhedonia, suicidality, and psychosocial functionality). Our findings suggest that ketamine is effective across domains varyingly, with the strongest evidence being for its ability to reduce suicidality. The rapid acting nature of ketamine further supports its use in treating suicidality and potentially preventing the completion of suicide. Evidence for the effectiveness of ketamine in other domains is weak, primarily due to a lack of robust studies specifically designed to assess these domains as primary outcomes. Future studies should scrutinize the effects of ketamine on specific domains of depression to optimize its implementation.

Esketamine for treatment‑resistant depression: A review of clinical evidence (Review)

Treatment-resistant depression (TRD) is a challenge for psychiatrists, even after more than seven decades since the first antidepressants were used in clinical practice. Non-monoaminergic-based drugs with antidepressant properties have been developed, but to date, only esketamine and brexanolone have been approved for TRD and postpartum depression, respectively. A narrative review on the efficacy and safety of esketamine in the main categories of depressive disorders has been conducted through four electronic databases (Pubmed, Cochrane, EMBASE and Clarivate/Web of Science) The primary objective of the present review was to find evidence that may support the usefulness of esketamine for patients diagnosed with TRD as well as data about its potential adverse effects in the short and long term. A total of 14 papers were reviewed, and their results support the recommendation of esketamine for treatment of TRD as an add-on to antidepressants, but more data is needed in order to assess its long-term efficacy and safety. It must also be mentioned that there have been a few trials which did not report a significant effect on the severity of depressive symptoms with esketamine in TRD, therefore, caution is indicated for patients initiated on this adjuvant agent. There has been insufficient data to formulate specific guidelines about esketamine administration because evidence about favorable or negative prognostic factors of this treatment has been lacking, and the duration of its administration has not been unanimously accepted. Novel directions for research have been identified, especially in the case of patients with TRD and substance use disorders, geriatric or bipolar depression or in major depression with psychotic features.

Evaluation of Ethnicity Effect on Intranasal Esketamine Pharmacokinetics by Population Pharmacokinetic Modeling Using Data From a Japanese Phase 2b Study

Esketamine is used for the treatment of treatment-resistant depression in many countries. A population pharmacokinetic (popPK) model of esketamine and its metabolite (noresketamine) has been previously developed, which included Asian race and Japanese ethnicity as covariates on their exposures. The present study aimed to update the popPK model by adding new data from a phase 2b study in Japanese patients and reassess intrinsic and extrinsic factors on esketamine and noresketamine exposures. The updated model identified the effects of body weight on the fraction of the esketamine dose absorbed in the nasal cavity and elimination rate constant of esketamine, and Asian race on the apparent clearance of noresketamine. The model predicted that an increase of 30 kg of body weight would decrease esketamine exposures by ≈20%. Noresketamine exposures would be affected by Asian race and body weight. However, those newly identified covariates were not considered to have clinically relevant impacts, and therefore dose adjustments were not necessary. In conclusion, the popPK model of esketamine and noresketamine was successfully updated and suggested that interindividual variability of esketamine exposures can be better explained by body weight, rather than by race/ethnicity. The new findings obtained in this study should be useful information for the further development of esketamine and for clinical practice in the future.

Lipid and Polymeric Nanoparticles: Successful Strategies for Nose-to-Brain Drug Delivery in the Treatment of Depression and Anxiety Disorders

Intranasal administration has gained an increasing interest for brain drug delivery since it allows direct transport through neuronal pathways, which can be quite advantageous for central nervous system disorders, such as depression and anxiety. Nanoparticles have been studied as possible alternatives to conventional formulations, with the objective of improving drug bioavailability. The present work aimed to analyze the potential of intranasal nanoparticle administration for the treatment of depression and anxiety, using the analysis of several studies already performed. From the carried-out analysis, it was concluded that the use of nanoparticles allows the drug's protection from enzymatic degradation, and the modulation of its components allows controlled drug release and enhanced drug permeation. Furthermore, the results of in vivo studies further verified these systems' potential, with the drug reaching the brain faster and leading to increased bioavailability and, consequently, therapeutic effect. Hence, in general, the intranasal administration of nanoparticles leads to a faster onset of action, with increased and prolonged brain drug concentrations and, consequently, therapeutic effects, presenting high potential as an alternative to the currently available therapies for the treatment of depression and anxiety.

Esketamine and Psilocybin—The Comparison of Two Mind-Altering Agents in Depression Treatment: Systematic Review

This publication discusses two compounds belonging to the psychoactive substances group which are studied in the context of depression treatment—psilocybin and esketamine. The former is a naturally occurring psychedelic. The latter was invented in the laboratory exactly 60 years ago. Although the substances were controversial in the past, recent studies indicate the potential of those substances as novel antidepressant agents. The PubMed/MEDLINE database was used to identify articles for systematic review, using the following search terms: (depression) AND (psilocybin) OR (ketamine). From 617 items, only 12 articles were obtained in the final analyses. Three articles were devoted to psilocybin in depression treatment and nine to esketamine. In most studies, esketamine showed a significant reduction in both depressive symptoms and suicidal ideation shortly after intake and after a month of treatment compared to baseline and to standard-of-care antidepressant agents. Psilocybin’s antidepressive effects occurred one day after intake and after 6–7 weeks of treatment and were maintained for up to 6 or 8 months of follow-up. One study indicated that psilocybin’s effects are comparable with and may be superior to escitalopram treatment. Both esketamine and psilocybin demonstrated rapid and long-term effects in reducing depression symptoms and, after overcoming some limitations, may be considered as novel antidepressant agents in future.

Different symptomatic improvement pattern revealed by factor analysis between placebo response and response to Esketamine in treatment resistant depression

AIMS

The aim of this study is to determine whether there is difference in the change in each symptom of depression and in symptomatic improvement pattern between placebo and antidepressant responses.

METHODS

Using data from a randomized, double-blind (DB), placebo-controlled trial of esketamine (ESK) in patients with treatment-resistant depression (TRD), we conducted exploratory analyses. To determine differences in the change in each depressive symptom on the MADRS subscale between placebo and antidepressant responses, a two-way factorial analysis was conducted using the amount of change on Day 2 and 28 of treatment. In addition, exploratory and confirmatory factor analyses were conducted on the MADRS subtotal variables on Day 2 and 28 of treatment to determine symptomatic improvement pattern between placebo response and antidepressant responses.

RESULTS

We found that as well as MADRS total score, each subscale of MADRS score did not significantly differ between esketamine and placebo at Day 2 and 28. On the other hand, factor analysis revealed that the factor structure of the response was different between esketamine and placebo at the 2nd day. There was no difference in the factor structure between esketamine and placebo in response on Day 28 of treatment.

CONCLUSION

Factor analysis revealed different patterns of symptom improvement in the early phase of the intervention between esketamine and placebo. This finding suggests that a data driven approach may provide detailed efficacy information in clinical trials for antidepressants.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02918318. Registered: 28 September 2016.

The efficacy and safety of adjunctive intranasal esketamine treatment in major depressive disorder: a systematic review and meta-analysis

INTRODUCTION

Intranasal (IN) esketamine represents an innovative treatment for individuals with treatment resistant depression and depression with suicidal ideation and behavior. Herein, we synthesize extant long-term studies (≥ 4 weeks) regarding this treatment.

RESEARCH DESIGN AND METHODS

The interventional studies of IN esketamine in patients with depression having a study period of at least four weeks were included for our synthesis. A meta-analysis was undertaken for the efficacy and safety parameters of adjunctive IN esketamine vs IN placebo with an oral antidepressant. The data excluded from meta-analysis were synthesized narratively.

RESULTS

After pooling data from seven randomized controlled trials, treatment with adjunctive IN esketamine vs IN placebo was safe overall, and more effective at decreasing depressive symptoms (d = -0.239; 95%CI = -0.335,-0.142;p < 0.0001), with higher response (RR = 1.221; 95% CI = 1.055,1.428; p = 0.017) and remission (RR = 1.366; 95% CI = 1.182,1.578; p < 0.0001) rates. The year-long trials showed that treatment with adjunctive IN esketamine led to lower relapse rates with no considerable long-term side effects.

CONCLUSION

Intranasal esketamine was demonstrated to be safe, well tolerated, and rapidly effective in individuals with treatment resistant depression, suicidal ideation, and suicidal behavior.

Is (R)-ketamine a Potential Therapeutic Agent for Treatment-Resistant Depression with Less Detrimental Side Effects? A Review of Molecular Mechanisms Underlying Ketamine and its Enantiomers

Approximately one-third of individuals with major depressive disorder are resistant to conventional antidepressants (i.e., monoamine-based therapies), and, even among respondents, a proper therapeutic effect may require weeks of treatment. Ketamine, a racemic mixture of the two enantiomers, (R)-ketamine and (S)-ketamine, is an N-methyl-d-aspartate receptor (NMDAR) antagonist and has been shown to have rapid-acting antidepressant properties in patients with treatment-resistant depression (TRD). Although (R)-ketamine has a lower affinity for NMDAR, it presents greater potency and longer-lasting antidepressant properties, with no major side effects, than racemic ketamine or (S)-ketamine in preclinical findings. Thereby, ketamine and its enantiomers have not only an antagonistic effect on NMDAR but also a strong synaptogenic-modulatory effect, which is impaired in TRD pathophysiology. In this review, we summarize the current evidence regarding the modulation of neurotransmission, neuroplasticity, and neural network activity as putative mechanisms of these rapid-acting antidepressants, highlighting differences on intracellular signaling pathways of synaptic proteins such as mammalian target of rapamycin (mTOR), extracellular signal-regulated kinase (ERK) and brain-derived neurotrophic factor (BDNF). In addition, we discuss probable mechanisms involved in the side effects of ketamine and its enantiomers.

Efficacy and Safety of Esketamine Combined with Antidepressants for Treatment-Resistant Depression: A Meta-Analysis

OBJECTIVE

To evaluate the efficacy and safety of esketamine + antidepressant in treatment-resistant depression.

METHODS

We searched PubMed, Web of Science, Embase, CNKI, and Wanfang databases to obtain published information on esketamine + antidepressant from inception to July 2022. We searched for randomized controlled studies on the treatment of depression with a double-blind induction phase. Outcome indicators included changes in Montgomery-Asberg Depression Rating Scale (MADRS) scores before and after treatment, effective response rate, remission rate, and changes in self-rating depression scale (SDS). We analyzed data using Review Manager 5.4 and assessed the quality of evidence using Grading of Recommendations Assessment, Development, and Evaluation (GRADE) analysis.

RESULTS

A total of seven articles were included, including 701 patients in the esketamine + antidepressant group and 551 in the placebo group. Meta-analysis results showed that esketamine + antidepressant could improve the MADRS score in patients with treatment-resistant depression (MD = -2.68, 95% CI -3.98 to -1.37, P < 0.0001), SDS (MD = -2.9, 95% CI -4.01 to -1.79, P < 0.00001), response rate at the end of the double-blind induction period (RR = 1.28, 95% CI 1.12 to 1.46, P = 0.0002), remission rate at the end of the double-blind induction period (RR = 1.39, 95% CI 1.18 to 1.63, P < 0.0001), Five-Dimensional Health Scale (EQ-5D-5L) (MD = 0.05, 95% CI 0.02 to 0.08, P = 0.00009), Visual Analogue Scale of Health Status (EQ-VAS) (MD = 5.54, 95% CI 2.37 to 8.71, P = 0.0006).

CONCLUSION

Esketamine + antidepressant has an obvious curative effect in treatment-resistant depression and can rapidly improve depression in patients, quality of life and satisfaction, but minor adverse reactions can occur.