Comparable efficacy and safety of 8 weeks treatment with agomelatine 25-50mg or fluoxetine 20-40mg in Asian out-patients with major depressive disorder

Agomelatine: An astounding sui-generis antidepressant?

Major depressive disorder (MDD) is one of the foremost causes of disability and premature death worldwide. Although the available antidepressants are effective and well tolerated, they also have many limitations. Therapeutic advances in developing a new drug's ultimate relation between MDD and chronobiology, which targets the circadian rhythm, have led to a renewed focus on psychiatric disorders. In order to provide a critical analysis about antidepressant properties of agomelatine, a detailed PubMed (Medline), Scopus (Embase), Web of Science (Web of Knowledge), Cochrane Library, Google Scholar, and PsycInfo search was performed using the following keywords: melatonin analog, agomelatine, safety, efficacy, adverse effects, pharmacokinetics, pharmacodynamics, circadian rhythm, sleep disorders, neuroplasticity, MDD, bipolar disorder, anhedonia, anxiety, generalized anxiety disorder (GAD), and mood disorders. Agomelatine is a unique melatonin analog with antidepressant properties and a large therapeutic index that improves clinical safety. It is a melatonin receptor agonist (MT1 and MT2) and a 5-HT2C receptor antagonist. The effects on melatonin receptors enable the resynchronization of irregular circadian rhythms with beneficial effects on sleep architectures. In this way, agomelatine is accredited for its unique mode of action, which helps to exert antidepressant effects and resynchronize the sleep-wake cycle. To sum up, an agomelatine has not only antidepressant properties but also has anxiolytic effects.

Antidepressant efficacy of Agomelatine: Meta-analysis of placebo controlled and active comparator studies

Agomelatine is a novel antidepressant that was developed to counter the adverse effects associated with the standard SSRIs and SNRIs that limited their usage. Publication bias was identified in antidepressant trials which can potentially overestimate the treatment efficacy. This meta-analysis was designed to assess the overall antidepressant effect of Agomelatine by pooling all the published and unpublished studies available till date. Studies conducted on adult patients who met with the criteria for MDD that evaluated efficacy of Agomelatine at acute phase (6-12weeks) and at long term phase (24weeks) were included. The primary efficacy measured with SMD of final mean scores of HAM-D and MADRS. Secondary efficacy measures of Response, remission and safety parameters were evaluated with relative risks. RevMan version 5.4 was used for analysis of both continuous (Standardized mean difference) and dichotomous outcomes (response, remission and all cause of discontinuation). Efficacy parameters were presented with 99% confidence intervals while safety parameters were presented with 95% CI. A total of 9233 patients were included from 27 studies. In acute phase placebo controlled studies, Agomelatine had a statistically significant SMD of - 0.24 (-0.39 to -0.09) and response rate of (1.25, 1.07-1.47). In comparison (RR 0.99, 0.92-1.07) Agomelatine is an effective antidepressant having similar efficacy with the currently used antidepressants.

The association between placebo arm inclusion and adverse event rates in antidepressant randomized controlled trials: An examination of the Nocebo Effect

BACKGROUND

Antidepressant efficacy is influenced by patient expectations and, in randomized controlled trials (RCTs), the probability of receiving a placebo. It is unclear whether tolerability demonstrates a similar pattern. This study aimed to determine whether study design influences adverse event (AE) rates in antidepressant trials for subjects receiving active treatment or placebo.

METHODS

RCTs comparing one antidepressant to another antidepressant, placebo, or both in major depressive disorder (MDD) (1996-2018) were retrieved from Medline and PsycINFO. Clinicaltrials.gov was searched for unpublished trials. Of 1,997 studies screened, 77 trials were included. Studies were classified as drug-drug, drug-drug-placebo, or drug-placebo based on design and overall number of subjects experiencing any AE was recorded. Subgroup meta-analysis of proportions and meta-regression techniques were used to compare AE rates across study designs in patients receiving active antidepressant treatment and placebo.

RESULTS

Among the actively treated, AE rates were lower in drug-drug trials (58.5%) compared to drug-drug-placebo (75.7%) and drug-placebo (76.4%) (the model reported coefficients for percent differences between AE rates of different study designs were B=17.0, p<0.001 and B=17.8, p<0.001, respectively). AE rates in patients receiving placebo were not different between study designs.

LIMITATIONS

The present study is limited by the diverse range of study populations, variability in reporting of AEs, and specific antidepressants employed in the included trials.

CONCLUSIONS

The inclusion of a placebo arm in the study design was unexpectedly associated with higher rates of AEs among patients receiving active medication in antidepressant trials. This observation has important implications for interpretation of trial tolerability findings.

Aloysia polystachya (Griseb.) Moldenke (Verbenaceae) powdered leaves are effective in treating anxiety symptoms: A phase-2, randomized, placebo-controlled clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Aloysia polystachya (Griseb.) Moldenke (Verbenaceae) is a plant traditionally used as medicine for anxiety symptoms. This activity was confirmed in preclinical studies. However, its efficacy was never studied in human clinical trials.

AIM OF THE STUDY

We aimed to test the hypothesis that the herbal medicine of A. polystachya is superior to placebo for the treatment of anxiety-related symptoms in adults after 8 weeks.

PATIENTS AND METHODS

This was a randomized, double-blind, placebo-controlled, phase-2 clinical trial. Fifty-four adults with self-reported anxiety symptoms were randomly allocated to receive either capsules containing A. polystachya powdered leaves (300 mg, twice a day) or placebo (maltodextrin), for 8 weeks. The intensity of anxiety symptoms was assessed by the Hamilton Anxiety Ranking Scale (HAM-A) at baseline and after 2, 4 and 8 weeks. All analyses were adjusted for physical activity (assessed by the International Physical Activity Questionnaire [IPAQ], short version) and gender.

RESULTS

We confirmed the presence of acteoside (chromatographic analysis) and carvone and limonene (gas chromatography) as major constituents in our plant material. Only patients that received A. polystachya experienced a significant decrease in their HAM-A scores, with none or mild side-effects.

CONCLUSION

Administration of powdered leaves of A. polystachya, rich in acteoside, carvone and limonene, to adults with anxiety symptoms was significantly superior to placebo in decreasing HAM-A scores after 8 weeks. This finding confirms the ethnopharmacological use of this plant for anxiety symptoms.

Agomelatine for depression: expanding the horizons?

INTRODUCTION

Agomelatine is an antidepressant with unique pharmacological actions; it is both a melatonin agonist and selective serotonin antagonist. Both actions combined are necessary for antidepressant efficacy. Effects on melatonin receptors enable resynchronisation of disrupted circadian rhythms with beneficial effects on sleep patterns. Areas covered: The issue of use of an antidepressant for depression co-morbid with somatic disorders is covered by the authors. A review of the literature from 2000 to August 2018 was undertaken using Scopus and Web of Science with the key words: agomelatine, depression, medical illness. Depression in Parkinson's disease, cardiovascular illness and type II diabetes is reviewed with evidence of efficacy. Bipolar depression and seasonal affective disorder may also react favourably. Agomelatine may have specific efficacy on symptoms of anhedonia. Expert opinion: Despite approval in some major jurisdictions, the drug has failed to gain registration in the United States. A defining issue may be questions about longer term efficacy: unequivocal effectiveness in placebo-controlled relapse prevention studies has not always been demonstrated. Continuation studies suggest maintenance of clinical responsiveness. A major disadvantage of the drug is its' potential hepatotoxicity and the need for repeated clinical laboratory tests.

Efficacy and Safety of Agomelatine vs Paroxetine Hydrochloride in Chinese Han Patients with Major Depressive Disorder: A Multicentre, Double-Blind, Noninferiority, Randomized Controlled Trial

PURPOSE

The purpose of this study is to investigate the efficacy, safety, and tolerability of agomelatine and paroxetine in Chinese Han patients with major depressive disorder (MDD).

METHODS

A 8-week, double-blind, randomized, parallel study was conducted in 14 medical centers in mainland China from December 2011 to September 2012. A total of 264 subjects with a primary Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnosis of MDD were randomly assigned to receive agomelatine 25-50 mg/d (n = 132) or paroxetine 20-40 mg/d (n = 132). The primary efficacy was evaluated by the decrease of Hamilton Depression Rating Scale (HAM-D17) scores. The secondary measurements of efficacy included Hamilton Anxiety Rating Scale, Montgomery-Asberg Depression Rating Scale, Sheehan Disability Scale, Clinical Global Impressions-Severity, and Clinical Global Impressions-Improvement. The laboratory test abnormity, and observed and self-reported adverse events were all assessed as the measurements of safety and tolerability.

RESULTS

Both the agomelatine and paroxetine groups showed significant improvement from baseline to the end point (P < 0.05) without between-group differences (P > 0.05). The mean decrease of HAM-D17 of agomelatine group was not inferior to the paroxetine group over the 8-week treatment (agomelatine 15.26 ± 6.44 vs paroxetine 14.87 ± 5.89, δ = 2.0; μA-μB 95% confidence interval, -1.13 to 1.91). The percentage of responders at the last postbaseline assessment was similar in the 2 groups on both HAM-D17 (agomelatine 66.15% vs paroxetine 63.49%) and Clinical Global Impressions-Improvement (agomelatine 79.09% vs paroxetine 80.36%). The anxiety (Hamilton Anxiety Rating Scale) and sleep symptoms (sleep items of HAM-D17) of the patients were improved significantly in the 2 groups at week 8 without between-group differences (P > 0.05). The incidence of overall adverse events was similar in the 2 groups (agomelatine 49.62% vs paroxetine 56.15%, P > 0.05). The incidence of adverse events in skin and subcutaneous tissue was higher in the paroxetine group than in the agomelatine group (none in agomelatine and 4.62% in paroxetine, P = 0.0144).

CONCLUSIONS

Agomelatine showed equivalent antidepressant efficacy to paroxetine in treating MDD patients after 8 weeks of treatment with an acceptable safety.

Agomelatine versus Sertraline: An Observational, Open-labeled and 12 Weeks Follow-up Study on Efficacy and Tolerability

Objective

In this open-labeled, 12 weeks follow-up study, we aimed to compare the efficacy and tolerability of agomelatine with sertraline

Methods

The outpatients of adult psychiatry clinic who have a new onset of depression and diagnosed as ‘major depressive episode’ by clinician according to the Diagnostic and Statistical Manual of Mental Disorders 4th edition and prescribed agomelatine (25 mg/day) or sertraline (50 mg/day) were included in the study.

Results

The decline of mean Montgomery-Asberg Depression Rating Scale (MADRS) scores of agomelatine group was significantly higher than the sertraline group at the end of 2nd week; however, the difference was not significant at the end of 3 months. Mean Clinical Global Impression-Improvement scale (CGI-I) scores of agomelatine group was lower than sertraline group at first week. Mean CGI-Severity scale and CGI-I scores were favour to sertraline group at the end of the study. Remission rates were 46.7% for sertraline group and 33.3% for agomelatine group while response rates were 76.7% for both groups. Any patient from agomelatine group dropped-out due to adverse effects. The amount of side effects was also less with agomelatine.

Conclusion

Agomelatine has a rapid onset efficacy on depressive symptoms and this can be beneficial for some critical cases. Considering MADRS scores, agomelatine seems to have similar efficacy with sertraline but we also point the need for long term studies since CGI scores were favour to sertraline group at the end of the study. Agomelatine has a favourable tolerability profile both in terms of discontinuation and the amount of side effects compared to sertraline.

Characterisation of Agomelatine-Induced Increase in Liver Enzymes: Frequency and Risk Factors Determined from a Pooled Analysis of 7605 Treated Patients

BACKGROUND

Antidepressant-induced liver injury is a major concern and a liver monitoring scheme has been recommended by the European Medicines Agency for agomelatine.

OBJECTIVE

The objective of this study was to assess the liver safety and identify the characteristics of patients who developed a significant increase in transaminases whilst taking agomelatine.

METHOD

A retrospective pooled analysis of changes in transaminase levels in 9234 patients treated with agomelatine (25 or 50 mg/day; n = 7605) or placebo (n = 1629) from 49 phase II and III studies was undertaken. A significant increase in transaminase levels was defined as an increase to >3 times the upper limit of normal (ULN) (>3 × ULN). Final causality was determined in a case-by-case review by five academic experts.

RESULTS

Serum transaminases increased to >3 × ULN in 1.3 and 2.5 % of patients treated with 25 and 50 mg of agomelatine, respectively, compared with 0.5 % for placebo. The onset of increased transaminases occurred before 12 weeks in 64 % of patients. The median time to recovery (to ≤2 × ULN) was 14 days following treatment withdrawal. Liver function tests recovered in 36.1 % of patients despite continuation of agomelatine, suggesting the presence of a liver adaptive mechanism. No cases of acute liver failure or fatal outcome occurred. Patients with elevated transaminases at baseline, secondary to obesity/fatty liver disease, had an equally increased risk of developing further elevations of transaminases with agomelatine and placebo.

CONCLUSION

Incidence of abnormal transaminases was low and dose dependent. No specific population was identified regarding potential risk factors. Withdrawal of agomelatine led to rapid recovery, and some patients exhibited an adaptive phenomenon. Overall, in clinical trials, the liver profile of agomelatine seems safe when serum transaminases are monitored.

Network Meta-Analysis and Cost-Effectiveness Analysis of New Generation Antidepressants

BACKGROUND

Major depressive disorder (MDD) impacts health, quality of life and workplace productivity. Antidepressant treatment is the primary therapeutic intervention. This study assessed the efficacy and tolerability of new generation antidepressants and their cost-effectiveness in the Singapore healthcare system.

METHODS

We conducted a systematic search for head-to-head randomised controlled trials on ten antidepressants (agomelatine, duloxetine, escitalopram, fluvoxamine, fluoxetine, mirtazapine, paroxetine, sertraline, trazodone and venlafaxine) employed as monotherapy in acute MDD management. We performed a network meta-analysis to compare their relative efficacy. The outcome measures for efficacy were response and remission rate, and mean change in Hamilton Depression Rating Scale (HDRS) score; and for tolerability, study withdrawal rates due to adverse events. To evaluate their relative cost effectiveness, a decision tree simulating a cohort of MDD patients using antidepressant as monotherapy was constructed from a societal perspective over 6 months. We used effectiveness data from our network meta-analysis and local data on resource use for depression in Singapore. The incremental cost expected for each additional quality-adjusted life-year (QALY) gained was calculated and presented as the incremental cost-effectiveness ratio (ICER).

RESULTS

We identified 76 relevant articles for the network meta-analysis. Of the ten agents included in the analysis, mirtazapine and agomelatine were most efficacious in achieving response and remission, respectively. Mirtazapine and duloxetine resulted in the greatest magnitude of change in the HDRS score. Agomelatine, escitalopram and sertraline were the best tolerated of the drugs analysed, while duloxetine was the least well tolerated drug. Using a composite outcome of efficacy (response and remission rates) and tolerability, agomelatine, escitalopram and mirtazapine were the favoured treatments. In the cost-effectiveness analysis, apart from agomelatine, all the treatments were dominated by mirtazapine. Against mirtazapine, agomelatine was not cost effective given that its ICER exceeded the threshold value.

CONCLUSION

Agomelatine, escitalopram and mirtazapine had favourable balance between efficacy and tolerability. In addition, mirtazapine was a cost-effective option in the Singapore healthcare system.

Agomelatine versus other antidepressive agents for major depression

BACKGROUND

Major depressive disorder (MDD), or depression, is a syndrome characterised by a number of behavioural, cognitive and emotional features. It is most commonly associated with a sad or depressed mood, a reduced capacity to feel pleasure, feelings of hopelessness, loss of energy, altered sleep patterns, weight fluctuations, difficulty in concentrating and suicidal ideation. There is a need for more effective and better tolerated antidepressants to combat this condition. Agomelatine was recently added to the list of available antidepressant drugs; it is a novel antidepressant that works on melatonergic (MT1 and MT2), 5-HT 2B and 5-HT2C receptors. Because the mechanism of action is claimed to be novel, it may provide a useful, alternative pharmacological strategy to existing antidepressant drugs.

OBJECTIVES

The objective of this review was 1) to determine the efficacy of agomelatine in alleviating acute symptoms of major depressive disorder in comparison with other antidepressants, 2) to review the acceptability of agomelatine in comparison with other antidepressant drugs, and, 3) to investigate the adverse effects of agomelatine, including the general prevalence of side effects in adults.

SEARCH METHODS

We searched the Cochrane Collaboration's Depression, Anxiety and Neurosis Review Group's Specialised Register (CCDANCTR) to 31 July 2013. The CCDANCTR includes relevant randomised controlled trials from the following bibliographic databases: CENTRAL (the Cochrane Central Register of Controlled Trials) (all years), EMBASE (1974 onwards), MEDLINE (1950 onwards) and PsycINFO (1967 onwards). We checked reference lists of relevant studies together with reviews and regulatory agency reports. No restrictions on date, language or publication status were applied to the search. Servier Laboratories (developers of agomelatine) and other experts in the field were contacted for supplemental data.

SELECTION CRITERIA

Randomised controlled trials allocating adult participants with major depression to agomelatine versus any other antidepressive agent.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and a double-entry procedure was employed. Information extracted included study characteristics, participant characteristics, intervention details and outcome measures in terms of efficacy, acceptability and tolerability.

MAIN RESULTS

A total of 13 studies (4495 participants) were included in this review. Agomelatine was compared to selective serotonin reuptake inhibitors (SSRIs), namely paroxetine, fluoxetine, sertraline, escitalopram, and to the serotonin-norepinephrine reuptake inhibitor (SNRI), venlafaxine. Participants were followed up for six to 12 weeks. Agomelatine did not show any advantage or disadvantage over the other antidepressants for our primary outcome, response to treatment (risk ratio (RR) 1.01, 95% confidence interval (CI) 0.95 to 1.08, P value 0.75 compared to SSRIs, and RR 1.06; 95% CI 0.98 to 1.16, P value 0.16 compared to venlafaxine). Also, agomelatine showed no advantage or disadvantage over other antidepressants for remission (RR 0.83; 95% CI 0.68 to 1.01, P value 0.07 compared to SSRIs, and RR 1.08; 95% CI 0.94 to 1.24, P value 0.73 compared to venlafaxine). Overall, agomelatine appeared to be better tolerated than venlafaxine in terms of lower rates of drop outs (RR 0.40; 95% CI 0.24 to 0.67, P value 0.0005), and showed the same level of tolerability as SSRIs (RR 0.95; 95% CI 0.83 to 1.09, P value 0.44). Agomelatine induced a lower rate of dizziness than venlafaxine (RR 0.19, 95% CI 0.06 to 0.64, P value 0.007).With regard to the quality of the body of evidence, there was a moderate risk of bias for all outcomes, due to the number of included unpublished studies. There was some heterogeneity, particularly between published and unpublished studies. The included studies were conducted in inpatient and outpatient settings, thus limiting the generalisability of the results to primary care settings. With regard to precision, the efficacy outcomes were precise, but the tolerability outcomes were mostly imprecise. Publication bias was variable and depended on the outcome of the trial. Our review included unpublished studies, and we think that this reduced the impact of publication bias. The overall methodological quality of the studies was not very good. Almost all of the studies were sponsored by the pharmaceutical company that manufactures agomelatine (Servier), and some of these were unpublished. Attempts to contact the pharmaceutical company Servier for additional information on all unpublished studies were unsuccessful.

AUTHORS' CONCLUSIONS

Agomelatine did not seem to provide a significant advantage in efficacy over other antidepressive agents for the acute-phase treatment of major depression. Agomelatine was better tolerated than paroxetine and venlafaxine in terms of overall side effects, and fewer participants treated with agomelatine dropped out of the trials due to side effects compared to sertraline and venlafaxine, but data were limited because the number of included studies was small. We found evidence that compared agomelatine with only a small number of other active antidepressive agents, and there were only a few trials for each comparison, which limits the generalisability of the results. Moreover, the overall methodological quality of the studies was low, and, therefore, no firm conclusions can be drawn concerning the efficacy and tolerability of agomelatine.