5-HTT and 5-HT(1A) receptor occupancy of the novel substance vortioxetine (Lu AA21004). A PET study in control subjects

Perspectives on the impact of vortioxetine on the treatment armamentarium of major depressive disorder

INTRODUCTION

Major Depressive Disorder (MDD) is a mental health issue that significantly affects patients' quality of life and functioning. Despite available treatments, many patients continue to suffer due to incomplete symptom resolution and side effects.

AREAS COVERED

This manuscript examines Vortioxetine's role in Major Depressive Disorder (MDD) treatment, highlighting its potential to reshape therapeutic strategies due to its unique Multimodal action and proven broad-spectrum efficacy in multiple depressive domains. A detailed examination of Vortioxetine's pharmacological aspects, including indications, dosage, pharmacodynamics, and pharmacokinetics, is provided, emphasizing its safety and effectiveness. The discussion extends to Vortioxetine's role in acute-phase treatment and maintenance of MDD and its profound impact on specialized depression domains.

EXPERT OPINION

Vortioxetine is distinguished for its novel multimodal serotonin modulation mechanism, showcasing significant promise as an innovative treatment for MDD. Its efficacy, which is dose-dependent, along with a commendable tolerability profile, positions it as a potential leading option for initial treatment strategies. The discourse on dosage titration, particularly the strategy of initiating treatment at lower doses followed by gradual escalation, underscores the approach toward minimizing initial adverse effects while optimizing therapeutic outcomes, aligning with the principles of personalized medicine in psychiatric care.

Update Lessons from PET Imaging Part II: A Systematic Critical Review on Therapeutic Plasma Concentrations of Antidepressants

BACKGROUND

Compared with antipsychotics, the relationship between antidepressant blood (plasma or serum) concentrations and target engagement is less well-established.

METHODS

We have discussed the literature on the relationship between plasma concentrations of antidepressant drugs and their target occupancy. Antidepressants reviewed in this work are citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, venlafaxine, duloxetine, milnacipran, tricyclic antidepressants (amitriptyline, nortriptyline, and clomipramine), bupropion, tranylcypromine, moclobemide, and vortioxetine. Four electronic databases were systematically searched.

RESULTS

We included 32 articles published 1996-2022. A strong relationship between serotonin transporter (SERT) occupancy and drug concentration is well established for selective serotonin reuptake inhibitors. Lower limits of recommended therapeutic reference ranges largely corroborate with the findings from positron emission tomography studies (80% SERT occupancy). Only a few novel studies have investigated alternative targets, that is, norepinephrine transporters (NETs), dopamine transporters (DATs), or monoamine oxidase A (MAO-A). For certain classes of drugs, positron emission tomography study data are inconclusive. Low DAT occupancy after bupropion treatment speculates its discussed mechanism of action. For MAO inhibitors, a correlation between drug concentration and MAO-A occupancy could not be established.

CONCLUSIONS

Neuroimaging studies are critical in TDM-guided therapy for certain antidepressants, whereas for bupropion and MAO inhibitors, the available evidence offers no further insight. Evidence for selective serotonin reuptake inhibitors is strong and justifies a titration toward suggested ranges. For SNRIs, duloxetine, and venlafaxine, NETs are sufficiently occupied, well above the SERT efficacy threshold. For these drugs, a titration toward higher concentrations (within the recommended range) should be considered in case of no response at lower concentrations.

SSRIs in the Treatment of Depression: A Pharmacological CUL-DE-SAC?

The widespread adoption of selective serotonin reuptake inhibitors (SSRIs) as first-line pharmacological treatments in the management of clinical depression transformed the landscape of drug therapy for this condition. SSRIs are safer and better tolerated than the tricyclic antidepressants (TCAs) that they replaced. However, they have limitations that may have placed a ceiling on the expectations of first-line pharmacological treatment. Notable problems with SSRIs include induction of anxiety on treatment initiation, delayed onset of significant therapeutic effect, sexual dysfunction, sleep disturbance and overall modest efficacy. The latter is linked with an inability of SSRIs to effectively treat syndromes of anhedonia and cognitive impairment. Combined serotonin and noradrenaline reuptake inhibitors (SNRIs), such as venlafaxine, have produced some limited improvements over SSRIs in efficacy, at the cost of a greater side-effect burden. Attempts to supplement serotonin reuptake activity with actions at serotonin receptor sub-types have not yet yielded substantial benefits; however, vortioxetine may provide more utility in the management of cognitive impairment. Future advances might come from the development of SNRIs, which more closely mimic the actions of effective TCAs. There may also be possible benefits to be derived from combining SSRIs with 5-HT4 receptor agonists and 5-HT7 receptor antagonists.

SLIC-Occ: functional segmentation of occupancy images improves precision of EC50 images

BACKGROUND

Drug occupancy studies with positron emission tomography imaging are used routinely in early phase drug development trials. Recently, our group introduced the Lassen Plot Filter, an extended version of the standard Lassen plot to estimate voxel-level occupancy images. Occupancy images can be used to create an EC50 image by applying an Emax model at each voxel. Our goal was to apply functional clustering of occupancy images via a clustering algorithm and produce a more precise EC50 image while maintaining accuracy.

METHOD

A digital brain phantom was used to create 10 occupancy images (corresponding to 10 different plasma concentrations of drug) that correspond to a ground truth EC50 image containing two bilateral local "hot spots" of high EC50 (region-1: 25; region-2: 50; background: 6-10 ng/mL). Maximum occupancy was specified as 0.85. An established noise model was applied to the simulated occupancy images and the images were smoothed. Simple Linear Iterative Clustering, an existing k-means clustering algorithm, was modified to segment a series of occupancy images into K clusters (which we call "SLIC-Occ"). EC50 images were estimated by nonlinear estimation at each cluster (post SLIC-Occ) and voxel (no clustering). Coefficient of variation images were estimated at each cluster and voxel, respectively. The same process was also applied to human occupancy data produced for a previously published study.

RESULTS

Variability in EC50 estimates was reduced by more than 80% in the phantom data after application of SLIC-Occ to occupancy images with only minimal loss of accuracy. A similar, but more modest improvement was achieved in variability when SLIC-Occ was applied to human occupancy images.

CONCLUSIONS

Our results suggest that functional segmentation of occupancy images via SLIC-Occ could produce more precise EC50 images and improve our ability to identify local "hot spots" of high effective affinity of a drug for its target(s).

Broad Serotonergic Actions of Vortioxetine as a Promising Avenue for the Treatment of L-DOPA-Induced Dyskinesia

Parkinson's Disease (PD) is a neurodegenerative disorder characterized by motor symptoms that result from loss of nigrostriatal dopamine (DA) cells. While L-DOPA provides symptom alleviation, its chronic use often results in the development of L-DOPA-induced dyskinesia (LID). Evidence suggests that neuroplasticity within the serotonin (5-HT) system contributes to LID onset, persistence, and severity. This has been supported by research showing 5-HT compounds targeting 5-HT1A/1B receptors and/or the 5-HT transporter (SERT) can reduce LID. Recently, vortioxetine, a multimodal 5-HT compound developed for depression, demonstrated acute anti-dyskinetic effects. However, the durability and underlying pharmacology of vortioxetine's anti-dyskinetic actions have yet to be delineated. To address these gaps, we used hemiparkinsonian rats in Experiment 1, examining the effects of sub-chronic vortioxetine on established LID and motor performance. In Experiment 2, we applied the 5-HT1A antagonist WAY-100635 or 5-HT1B antagonist SB-224289 in conjunction with L-DOPA and vortioxetine to determine the contributions of each receptor to vortioxetine's effects. The results revealed that vortioxetine consistently and dose-dependently attenuated LID while independently, 5-HT1A and 5-HT1B receptors each partially reversed vortioxetine's effects. Such findings further support the promise of pharmacological strategies, such as vortioxetine, and indicate that broad 5-HT actions may provide durable responses without significant side effects.

PET as a Translational Tool in Drug Development for Neuroscience Compounds

In central nervous system drug discovery programs, early development of new chemical entities (NCEs) requires a multidisciplinary strategy and a translational approach to obtain proof of distribution, proof of occupancy, and proof of function in specific brain circuits. Positron emission tomography (PET) provides a way to assess in vivo the brain distribution of NCEs and their binding to the target of interest, provided that radiolabeling of the NCE is possible or that a suitable radioligand is available. PET is therefore a key tool for early phases of drug discovery programs. This review will summarize the main applications of PET in early drug development and discuss the usefulness of PET microdosing studies performed with direct labelling of the NCE and PET occupancy studies. The purpose of this review is also to propose an alignment of the nomenclatures used by drug metabolism and pharmacokinetic scientists and PET imaging scientists to indicate key pharmacokinetic parameters and to provide guidance in the performance and interpretation of PET studies.

The relationship between dose and serotonin transporter occupancy of antidepressants-a systematic review

Brain imaging techniques enable the visualization of serotonin transporter (SERT) occupancy as a measure of the proportion of SERT blocked by an antidepressant at a given dose. We aimed to systematically review the evidence on the relationship between antidepressant dose and SERT occupancy. We searched PubMed and Embase (last search 20 May 2021) for human in vivo, within-subject PET, or SPECT studies measuring SERT occupancy at any dose of any antidepressant with highly selective radioligands ([¹¹C]-DASB, [¹²³I]-ADAM, and [¹¹C]-MADAM). We summarized and visualized the dose-occupancy relationship for antidepressants across studies, overlaying the plots with a curve based on predicted values of a standard 2-parameter Michaelis-Menten model fitted using the observed data. We included seventeen studies of 10 different SSRIs, SNRIs, and serotonin modulators comprising a total of 294 participants, involving 309 unique occupancy measures. Overall, following the Michaelis-Menten equation, SERT occupancy increased with a higher dose in a hyperbolic relationship, with occupancy increasing rapidly at lower doses and reaching a plateau at approximately 80% at the usual minimum recommended dose. All the studies were small, only a few investigated the same antidepressant, dose, and brain region, and few reported information on factors that may influence SERT occupancy. The hyperbolic dose-occupancy relationship may provide mechanistic insight of relevance to the limited clinical benefit of dose-escalation in antidepressant treatment and the potential emergence of withdrawal symptoms. The evidence is limited by non-transparent reporting, lack of standardized methods, small sample sizes, and short treatment duration. Future studies should standardize the imaging and reporting procedures, measure occupancy at lower antidepressant doses, and investigate the moderators of the dose-occupancy relationship.

EC50 images, a novel endpoint from PET target occupancy studies, reveal spatial variation in apparent drug affinity

PURPOSE

We recently introduced voxel-level images of drug occupancy from PET via our "Lassen plot filter." Occupancy images revealed clear dependence of ¹¹C-flumazenil displacement on dose of GABAa inhibitor, CVL-865, but with different scales in different brain regions. We hypothesized that regions requiring higher drug concentrations to achieve desired occupancy would have higher EC₅₀ values. We introduce an "EC₅₀ image" from human data to evaluate this hypothesis.

METHODS

Five healthy subjects were scanned with the nonselective GABAa tracer, ¹¹C-flumazenil, before and (twice) after administration of CVL-865. We created ten occupancy images and applied an E_max model locally to create one EC₅₀ image. We also performed simulations to confirm our observations of regional variation in EC₅₀ and to identify the main source of variability in EC₅₀.

RESULTS

As expected, the EC₅₀ image revealed spatial variation in apparent drug affinity. High EC₅₀ was found in areas of low occupancy for a given drug dose. Simulations demonstrated that sampling from an inadequate range of plasma drug concentrations could impair precision.

CONCLUSION

Our results argue for (a) confidence in the ability of the EC₅₀ images to identify regional differences and (b) a need to tailor the range of drug doses in an occupancy study to regularize the precision of the EC₅₀ throughout the brain. The EC₅₀ image could add value to early-phase drug development by identifying regional variation in affinity that might impact therapy or safety and by guiding dose selection for later-phase trials.

Tools for optimising pharmacotherapy in psychiatry (therapeutic drug monitoring, molecular brain imaging and pharmacogenetic tests): focus on antidepressants

Objectives: More than 40 drugs are available to treat affective disorders. Individual selection of the optimal drug and dose is required to attain the highest possible efficacy and acceptable tolerability for every patient.Methods: This review, which includes more than 500 articles selected by 30 experts, combines relevant knowledge on studies investigating the pharmacokinetics, pharmacodynamics and pharmacogenetics of 33 antidepressant drugs and of 4 drugs approved for augmentation in cases of insufficient response to antidepressant monotherapy. Such studies typically measure drug concentrations in blood (i.e. therapeutic drug monitoring) and genotype relevant genetic polymorphisms of enzymes, transporters or receptors involved in drug metabolism or mechanism of action. Imaging studies, primarily positron emission tomography that relates drug concentrations in blood and radioligand binding, are considered to quantify target structure occupancy by the antidepressant drugs in vivo. Results: Evidence is given that in vivo imaging, therapeutic drug monitoring and genotyping and/or phenotyping of drug metabolising enzymes should be an integral part in the development of any new antidepressant drug.Conclusions: To guide antidepressant drug therapy in everyday practice, there are multiple indications such as uncertain adherence, polypharmacy, nonresponse and/or adverse reactions under therapeutically recommended doses, where therapeutic drug monitoring and cytochrome P450 genotyping and/or phenotyping should be applied as valid tools of precision medicine.

Gastrointestinal side effects associated with antidepressant treatments in patients with major depressive disorder: A systematic review and meta-analysis

Gastrointestinal side effects (SEs) are frequently observed in patients with major depressive disorder (MDD) while taking antidepressants and may lead to treatment discontinuation. The aim of this meta-analysis is to provide quantitative measures on short-term rates of gastrointestinal SEs in MDD patients treated with second-generation antidepressants. An electronic search of the literature was conducted by using MEDLINE, ISI Web of Science - Web of Science Core Collection, and Cochrane Library databases. Eligible studies had to focus on the use of at least one of 15 antidepressants commonly used in MDD (i.e., agomelatine, bupropion, citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, levomilnacipran, mirtazapine, paroxetine, reboxetine, sertraline, venlafaxine, and vortioxetine) and report data on treatment-emergent gastrointestinal SEs (i.e. nausea/vomiting, diarrhoea, constipation, abdominal pain, dyspepsia, anorexia, increased appetite and dry mouth) within 12 weeks of treatment. Overall, 304 studies were included in the meta-analyses. All the considered antidepressants showed higher rates of gastrointestinal SEs than placebo. Escitalopram and sertraline were shown to be the least tolerated antidepressants on the gastrointestinal tract, being associated with all the considered SEs with the exception of constipation and increased appetite, while mirtazapine was shown to be the antidepressant with fewer side effects on the gut, being only associated with increased appetite. In conclusion, commonly used antidepressants showed different profiles of gastrointestinal SEs, possibly related to their mechanisms of action. The specific tolerability profile of each compound should be considered by clinicians when prescribing antidepressants in order to improve adherence to treatment and increase positive outcomes in patients with MDD.

Effect of vortioxetine vs. escitalopram on plasma BDNF and platelet serotonin in depressed patients

Escitalopram and vortioxetine are efficacious antidepressants. They directly target serotonin (5-HT) system, but vortioxetine mechanism of action is distinct from the one of selective serotonin reuptake inhibitors (SSRIs). Treatment with SSRIs decrease platelet 5-HT concentration and increase peripheral brain-derived neurotrophic factor (BDNF) levels. Since vortioxetine has a multimodal mechanism of action, it is expected to have a greater effect on circulatory BDNF concentration, compared to conventional antidepressants. This longitudinal study aimed to explore and compare the effects of 4-weeks of treatment with vortioxetine and escitalopram on plasma BDNF and platelet 5-HT concentration in patients with major depressive disorder (MDD). The results revealed that vortioxetine significantly increased plasma BDNF concentration (p = .018) and significantly decreased platelet 5-HT concentration (p < .001). Treatment with escitalopram significantly decreased platelet 5-HT concentration (p < .001), but it did not affect plasma BDNF concentration (p = .379). Response to vortioxetine was not predicted by baseline plasma BDNF or platelet 5-HT concentration, but response to escitalopram was predicted by baseline platelet 5-HT concentration. These effects might be due to vortioxetine unique mechanism of action, but the clinical implications are unclear. It remains to be determined whether this finding extends during long-term vortioxetine treatment, and which, if any, clinical effects emerge from BDNF increase.

Vortioxetine increases absence-like seizures in WAG/Rij rats but decreases penicillin- and pentylenetetrazole-induced seizures in Wistar rats

AIM

Depression is the major psychiatric disorder in patients with epilepsy. Vortioxetine is a novel antidepressant drug for the treatment of major depressive disorders. In the present study, effects of vortioxetine were evaluated in different experimental epilepsy models of rats.

MATERIALS AND METHODS

Fifty-six adult male Wistar rats and 28 WAG/Rij rats were divided into 12 groups of 7 rats each. Experiments were conducted with penicillin (500 IU, i.c.) and pentylenetetrazole models (50 mg/kg, intraperitoneally (i.p.)) in Wistar rats and genetic absence epileptic WAG/Rij rats. The vortioxetine (1, 5, or 10 mg/kg, i.p.) was evaluated in these three models. All groups were compared with their control groups.

RESULTS

In the penicillin-induced seizure model, 1, 5, or 10 mg/kg vortioxetine administration significantly decreased mean spike frequency. In the pentylenetetrazole-induced seizure model, 1, 5, or 10 mg/kg vortioxetine demonstrated a significant dose-dependent decrease in mean spike frequency, an increase in the latency to minor and major seizures, and a decrease in total duration of major seizure and convulsion stage. In genetic absence epileptic WAG/Rij rats, 1 mg/kg vortioxetine caused no significant alteration in the number and duration of SWDs compared to the controls, while 5 and 10 mg/kg doses of vortioxetine increased the number and duration of SWDs. Amplitude of the epileptiform activity did not change in any of the experimental epilepsy models.

CONCLUSION

The results of this study suggested that vortioxetine has anticonvulsant activity in penicillin- and pentylenetetrazole-induced seizure models. However, it exhibited proconvulsant activity in the absence epileptic WAG/Rij rats.

Vortioxetine as a new frontier in the treatment of chronic neuropathic pain: a review and update

Chronic neuropathic pain (CNP) is a disabling medical condition that impairs the health-related quality-of-life of affected patients. A high prevalence of anxiety, depression, sleep disturbance and cognitive impairment has frequently been reported in association with CNP, making the management of this disease complex and often multidisciplinary. Dual-acting agents such as selective serotonin and noradrenalin reuptake inhibitors (SNRIs) are considered particularly useful in the modulation of pain and in treatment of the mood disorders frequently associated with CNP. Recent evidence suggests that the top-down inhibitory control of pain involves the engagement and enhancement of descending endogenous opioidergic, cannabinoid and serotonergic systems, with the effect of serotonin being particularly related to the receptor subtypes that are preferentially activated; indeed serotonin induces analgesia via activation of 5-HT7 receptors and hyperalgesia via activation of 5-HT3 receptors. Vortioxetine (VO) is a novel multimodal serotonergic antidepressant with a unique mechanism of action. It has been demonstrated recently in experimental and clinical studies to have efficacy on pain hypersensitivity and on mood disorders. This drug inhibits the serotonin transporter with a high affinity, antagonises the 5-HT3, 5-HT1D and 5HT7 serotonin receptors, and activates the 5-HT1A and 5-HT1B receptors. In clinical studies, VO has proved effective at a dose of 10-20 mg/daily in short- and long-term treatment of patients with chronic orofacial pain, demonstrating a higher rate of clinical response and remission, a better acceptability, safety rate and tolerability, and a lower latency of action compared with other antidepressants. In the light of these recent findings, VO may be considered as a new pharmacological treatment also in relation to various types of CNP, particularly in elderly patients with concomitant mood disorders and cognitive impairment. The purpose of this review is to provide an up-to-date overview of the pharmacology and clinical applications of VO and to highlight its potential therapeutic properties and advantages in the management of CNP.

Identification and characterization of forced degradation products of vortioxetine by LC/MS/MS and NMR

Vortioxetine (VTX) is a novel multimodal antidepressant drug that affects the serotoninergic and noradrenergic systems. In this work, the forced degradation of VTX was studied according to (ICH) Q1A (R2) guidelines. The study revealed that VTX was stable under thermal stress conditions and hydrolytic stress conditions i.e., acidic, basic and neutral conditions. In contrast, six degradation products (DPs) were formed under photolytic and oxidative stress conditions. The DPs were identified and characterized by high-resolution LC/MS and LC/MS/MS. The structures of major DPs were further confirmed by the synthesis and characterization by ¹H and ¹³C NMR data. A possible mechanism for the formation of the VTX DPs via photolytic/oxidative stress degradation pathway was proposed.

[11 C]raclopride positron emission tomography study of dopamine-D2/3 receptor binding in patients with severe major depressive episodes before and after electroconvulsive therapy and compared to control subjects

AIM

The aim of the study was to test: (i) if D₂ /D₃ binding in three functional subsections of striatum is different in patients with severe major depressive episodes than in controls; and (ii) if this difference is normalized after electroconvulsive therapy (ECT).

METHODS

Nine inpatients were examined with positron emission tomography (PET) and the radioligand [¹¹ C]raclopride before and after an average of 8.4 ECT sessions. Treatment response was assessed using the Montgomery-Åsberg Depression Rating Scale. Nine age- and sex-matched controls were examined twice with PET and [¹¹ C]raclopride.

RESULTS

[¹¹ C]raclopride binding was significantly lower in all three subsections of striatum in patients compared to controls (Cohen's d_z , 1.14-1.68; P = 0.003-0.027). Montgomery-Åsberg Depression Ratings decreased significantly after ECT (P < 0.001; Cohen's d_z , 2.9). ECT had no statistically significant effect on [¹¹ C]raclopride binding, although post-ECT binding estimates were more similar to those obtained in controls in all subsections of striatum.

CONCLUSION

Using PET and [¹¹ C]raclopride, we found support for the notion that severe major depressive episodes are associated with significantly lower dopamine D₂ /D₃ binding in all three subsections of striatum compared to controls. We noted no significant effect on D₂ /D₃ binding in the patient group after response to ECT.

Pharmacokinetics and Safety of Vortioxetine in the Chinese Population

Introduction

Major depressive disorder (MDD) is associated with a significant burden of disease in China. Awareness and better access to treatments could help alleviate the burden associated with MDD. Because variations have been observed in the pharmacokinetics (PK) of antidepressants across different races and ethnicities, evaluation of the clinical pharmacology of vortioxetine in diverse populations remains important to assess the potential need for dose adjustments.

Methods

Data were pooled from two phase I open-label PK studies in healthy Chinese subjects, and one phase III double-blind noninferiority study in Chinese patients with MDD to describe the PK and safety data for vortioxetine. Doses in these studies ranged from 10 mg (single dose) to 10 and 20 mg (multiple daily doses). A population PK analysis of vortioxetine in the Chinese population was conducted using nonlinear mixed-effect modeling.

Results

In total, 186 individuals were included in the PK analysis: 79 healthy Chinese subjects and 107 Chinese patients with MDD. No clinically significant differences in the PK of vortioxetine were observed between the Chinese population and the previous data in non-Chinese populations. Because of a generally lower weight in the Chinese population compared with the non-Chinese population, exposures were 19% and 18% higher in the Chinese population than in the non-Chinese population (for maximum observed plasma concentration and area under the plasma concentration–time curve, respectively), which is not considered clinically relevant. A high prevalence of pruritus was observed in one phase I PK study (56% overall); however, this was not reflected in the phase III study in Chinese patients with MDD (0.8%).

Conclusions

The PK parameters of vortioxetine in Chinese subjects were comparable to previous data in non-Chinese subjects. Overall, no new safety concerns were raised among the Chinese population. On the basis of this analysis, the tolerability profile of vortioxetine in Chinese healthy subjects and in patients with MDD is expected to be comparable to that in the non-Chinese population.

Funding

H. Lundbeck A/S, Valby, Denmark.

Trial Registration

NCT01676571.

Electronic supplementary material

The online version of this article (10.1007/s12325-019-01092-4) contains supplementary material, which is available to authorized users.

Effect of clinically relevant doses of vortioxetine and citalopram on serotonergic PET markers in the nonhuman primate brain

Vortioxetine is a multimodal antidepressant approved for treatment of major depressive disorder. Preclinical studies have demonstrated that the mechanism of action of vortioxetine might be different from selective serotonin reuptake inhibitors (SSRIs), including larger serotonin (5-HT) release and direct modulation of several 5-HT receptors. In the current positron emission tomography (PET) study, we evaluated the mechanism of action of vortioxetine by comparing its effect to the SSRI citalopram on the binding of [¹¹C]AZ10419369 to the 5-HT_1B receptor in the nonhuman primate brain. Initially, the 5-HT transporter (5-HTT) binding of vortioxetine was determined by [¹¹C]MADAM PET measurements before and after administration of vortioxetine (0.1-3.0 mg/kg) and data were used to confirm clinically relevant dosing in subsequent PET measurements with [¹¹C]AZ10419369. The 5-HT_1B receptor binding was significantly decreased after 0.3 mg/kg of citalopram in the dorsal raphe nucleus (5%), as well as after 0.3 mg/kg of vortioxetine in six brain regions (~25%) or 1.0 mg/kg of vortioxetine in all 12 examined regions (~48%). Moreover, there was no effect of 1.0 mg/kg of vortioxetine on the binding of [¹¹C]Cimbi-36 to the 5-HT_2A receptor, which has comparable sensitivity to 5-HT release as [¹¹C]AZ10419369 binding. In conclusion, at clinically relevant doses, vortioxetine induced larger reductions in [¹¹C]AZ10419369 binding than citalopram. These observations suggest that vortioxetine binds to the 5-HT_1B receptor at clinically relevant doses. Future studies are warranted to evaluate the role of the 5-HT_1B receptor in the therapeutic effects of vortioxetine and as a potential target for the development of novel antidepressant drugs.

Vortioxetine: Clinical Pharmacokinetics and Drug Interactions

Vortioxetine is a novel antidepressant with multimodal activity currently approved for the treatment of major depressive disorder. Vortioxetine is orally administered once daily at 5- to 20-mg doses. The pharmacokinetics of vortioxetine are linear and dose proportional, with a mean terminal half-life of approximately 66 h and steady-state plasma concentrations generally achieved within 2 weeks of dosing. The mean absolute oral bioavailability of vortioxetine is 75%. No food effect on pharmacokinetics was observed. Vortioxetine is metabolized by cytochrome P450 enzymes and subsequently by uridine diphosphate glucuronosyltransferase. The major metabolite is pharmacologically inactive, and the minor pharmacologically active metabolite is not expected to cross the blood–brain barrier, making the parent compound primarily responsible for in-vivo activity. No clinically relevant differences were observed in vortioxetine exposure by sex, age, race, body size, and renal or hepatic function. Dose adjustment is only recommended for cytochrome P450 2D6 poor metabolizers based on polymorphism of the cytochrome P450 enzymes involved. Similarly, except for bupropion, a strong cytochrome P450 2D6 inhibitor, and rifampin, a broad cytochrome P450 inducer, co-administration of other drugs evaluated did not affect the vortioxetine exposure or safety profile in any clinically meaningful way. Pharmacodynamic studies demonstrated that vortioxetine achieved high levels of serotonin transporter occupancy in relevant brain areas, affected neurotransmitter levels in the cerebrospinal fluid, and modified abnormal resting state networks in the brain over the therapeutic dose range. Overall, vortioxetine can be administered in most populations studied to date without major dose adjustments; however, dose adjustments should be considered on a patient-by-patient basis.

Intravenous vortioxetine to accelerate onset of effect in major depressive disorder: a 2-week, randomized, double-blind, placebo-controlled study

This 2-week randomized, double-blind, placebo-controlled fixed-dose study (NCT02919501) explored the potential of accelerating onset of antidepressant efficacy and plasma exposure with single-dose intravenous vortioxetine at oral vortioxetine treatment initiation. Outpatients (ages 18-65 years) with major depressive disorder and a current depressive episode (Montgomery Åsberg Depression Rating Scale total score ≥30) were randomized to an initial single dose of either intravenous vortioxetine 17 mg (n = 27) or intravenous placebo (n = 28), both treatments followed by 2 weeks of oral vortioxetine (10 mg/day). From baseline to day 7, both groups exhibited fast and substantial improvements by approximately 14 Montgomery Åsberg Depression Rating Scale points, with no statistically significant treatment difference for this primary endpoint. Improvements were substantial already within 24 hours, with numerical treatment differences of 1.3 and 1.6 points at days 1 and 3, respectively, in favour of intravenous vortioxetine + oral vortioxetine. Pharmacokinetic data confirmed that intravenous vortioxetine facilitated reaching steady-state plasma concentration within 24 hours. Intravenous vortioxetine + oral vortioxetine was safe and well-tolerated, with nausea as the most common adverse event. This study supported intravenous vortioxetine as a means of rapidly reaching therapeutic vortioxetine blood levels.

Vortioxetine for Cognitive Enhancement in Major Depression: From Animal Models to Clinical Research

Objectives: Vortioxetine has already shown its efficacy in the acute and long-term treatment of major depressive disorder (MDD) and its potential interest in the prevention of relapse. The aim of this study was to review the current status of knowledge regarding its cognitive effects. Methods: We conducted a review of key data obtained from preclinical behavioral models and clinical trials in MDD focusing on vortioxetine-induced cognitive changes. Results: In animals, acute and chronic administration of vortioxetine improves performance on objective measures that cover a broad range of cognitive domains. In human, vortioxetine appears to be a useful treatment option in MDD patients with cognitive dysfunction. Conclusion: Vortioxetine constitutes a promising treatment for treatment of cognitive impairment in MDD, but its place in the therapeutic armamentarium still needs to be determined.

Cognitive impairment in depression: recent advances and novel treatments

In the past, little or no attention was paid to cognitive disorders associated with depression (a condition sometimes termed pseudodementia). However, recent years have seen a growing interest in these changes, not only because of their high frequency in acute-stage depression, but also because they have been found to persist, as residual symptoms (in addition to affective and psychomotor ones), in many patients who respond well to antidepressant treatment. These cognitive symptoms seem to impact significantly not only on patients' functioning and quality of life, but also on the risk of recurrence of depression. Therefore, over the past decade, pharmacological research in this field has focused on the development of new agents able to counteract not only depressive symptoms, but also cognitive and functional ones. In this context, novel antidepressants with multimodal activity have emerged. This review considers the different issues, in terms of disease evolution, raised by the presence of cognitive disorders associated with depression and considers, particularly from the neurologist's perspective, the ways in which the clinical approach to cognitive symptoms, and their interpretation to diagnostic and therapeutic ends, have changed in recent years. Finally, after outlining the pharmacodynamics and pharmacokinetics of the first multimodal antidepressant, vortioxetine, it reports the main results obtained with the drug in depressed patients, also in consideration of the ever-increasing evidence on its different mechanisms of action in animal models.

Vortioxetine Differentially Modulates MK-801-Induced Changes in Visual Signal Detection Task Performance and Locomotor Activity

Attention impairment is a common feature of Major Depressive Disorder (MDD), and MDD-associated cognitive dysfunction may play an important role in determining functional status among this patient population. Vortioxetine is a multimodal antidepressant that may improve some aspects of cognitive function in MDD patients, and may indirectly increase glutamate neurotransmission in brain regions classically associated with attention function. Previous non-clinical research suggests that vortioxetine has limited effects on attention. This laboratory previously found that vortioxetine did not improve attention function in animals impaired by acute scopolamine administration, using the visual signal detection task (VSDT). However, vortioxetine has limited effects on acetylcholinergic neurotransmission, and thus it is possible that attention impaired by other mechanisms would be attenuated by vortioxetine. This study sought to investigate whether acute vortioxetine administration can attenuate VSDT impairments and hyperlocomotion induced by the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist MK-801. We found that acute vortioxetine administration had no effect on VSDT performance on its own, but potentiated MK-801-induced VSDT impairments. Furthermore, vortioxetine had no effect on locomotor activity on its own, and did not alter MK-801-induced hyperlocomotion. We further investigated whether vortioxetine's effect on MK-801 could be driven by a kinetic interaction, but found that plasma and brain exposure for vortioxetine and MK-801 were similar whether administered alone or in combination. Thus, it appears that vortioxetine selectively potentiates MK-801-induced impairments in attention without altering its effects on locomotion, and further that this interaction must be pharmacodynamic in nature. A theoretical mechanism for this interaction is discussed.

Vortioxetine Treatment Reverses Subchronic PCP Treatment-Induced Cognitive Impairments: A Potential Role for Serotonin Receptor-Mediated Regulation of GABA Neurotransmission

Major depressive disorder (MDD) is associated with cognitive impairments that may contribute to poor functional outcomes. Clinical data suggests that the multimodal antidepressant vortioxetine attenuates some cognitive impairments in MDD patients, but the mechanistic basis for these improvements is unclear. One theory suggests that vortioxetine improves cognition by suppressing γ-amino butyric acid (GABA)ergic neurotransmission, thereby increasing glutamatergic activation. Vortioxetine’s effects on cognition, GABA and glutamate neurotransmission have been supported in separate experiments, but no empirical work has directly connected vortioxetine’s cognitive effects to those on GABA and glutamate neurotransmission. In this paper, we attempt to bridge this gap by evaluating vortioxetine’s effects in the subchronic PCP (subPCP) model, which induces impaired cognitive function and altered GABA and glutamate neurotransmission. We demonstrate that acute or subchronic vortioxetine treatment attenuated subPCP-induced deficits in attentional set shifting (AST) performance, and that the selective 5-HT₃ receptor antagonist ondansetron or the 5-HT reuptake inhibitor escitalopram could mimic this effect. Furthermore, acute vortioxetine treatment reversed subPCP-induced object recognition (OR) deficits in rats, while subchronic vortioxetine reversed subPCP-induced Object Recognition and object placement impairments in mice. Finally, subPCP treatment reduced GABA_B receptor expression in a manner that was insensitive to vortioxetine treatment, and subchronic vortioxetine treatment alone, but not in combination with subPCP, significantly increased GABA’s affinity for the GABA_A receptor. These data suggest that vortioxetine reverses cognitive impairments in a model associated with altered GABA and glutamate neurotransmission, further supporting the hypothesis that vortioxetine’s GABAergic and glutamatergic effects are relevant for cognitive function.

A prospective, longitudinal study of platelet serotonin and plasma brain-derived neurotrophic factor concentrations in major depression: effects of vortioxetine treatment

BACKGROUND

Various antidepressants occupy brain serotonin transporter (SERT), decrease platelet serotonin (5-HT) concentration, and normalize reduced plasma brain-derived neurotrophic factor (BDNF) concentrations in depressed patients. Vortioxetine is a recently introduced antidepressant with a multimodal mechanism of action. In addition to SERT inhibition, vortioxetine acts via different 5-HT receptors. To further elucidate its mechanism of action, we have investigated the effects of vortioxetine on platelet 5-HT and plasma BDNF concentrations in patients with major depression.

METHODS

Platelet 5-HT and plasma BDNF concentrations were determined in 44 healthy subjects at baseline and in 44 depressed patients before and after 4 weeks of treatment with vortioxetine (5-15 mg daily). Platelet 5-HT concentration was determined using the ortho-phthalaldehyde-enhanced fluorometric method, and plasma BDNF concentration using a commercial enzyme-linked immunosorbent assay (Quantikine ELISA, R&D Systems).

RESULTS

At baseline, platelet 5-HT concentrations did not differ between depressed and control subjects, but plasma BDNF values were lower (p = 0.011; ω = 0.80) in depressed patients than in healthy subjects. Vortioxetine treatment significantly (p < 0.0001; ω = 0.80) decreased platelet 5-HT concentration and significantly (p = 0.004; ω = 0.80) increased plasma BDNF concentration in depressed patients compared to their baseline values. Age, gender, and smoking were not significantly associated with platelet 5-HT and plasma BDNF concentrations.

CONCLUSION

Despite a novel mechanism of action, vortioxetine shares some common effects with other antidepressants. This study is the first to show that, in addition to clinical improvement, 4 weeks of treatment with vortioxetine (5-15 mg daily), decreased platelet 5-HT and increased plasma BDNF concentrations in depressed patients.

New advances in the treatment of generalized anxiety disorder: the multimodal antidepressant vortioxetine

Generalized Anxiety Disorder (GAD) is a persistent condition characterized by chronic anxiety, exaggerated worry and tension, mainly comorbid with Major Depressive Disorder (MDD). Currently, selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors are recommended as first-line treatment of GAD. However, some patients may not respond to the treatment or discontinue due to adverse effects. Vortioxetine (VRX) is a multimodal antidepressant with a unique mechanism of action, by acting as 5-HT3A, 5-HT1D and 5-HT7 receptor antagonist, partial agonist at the 5-HT1A and 5-HT1B receptors and inhibitor at the 5-HT transporter. Preliminary clinical trials showed contrasting findings in terms of improvement of the anxiety symptomatology and/or cognitive impairment. Here, we aim to systematically review the evidence currently available on the efficacy, safety and tolerability of VRX in the treatment of GAD. The generalizability of results on the efficacy of VRX in patients with anxiety symptomatology and GAD is limited due to few and contrasting RCTs so far available. Only two studies, of which one prevention relapse trial, reported a significant improvement in anxiety symptomatology compared to three with negative findings.

Differentiated effects of the multimodal antidepressant vortioxetine on sleep architecture: Part 2, pharmacological interactions in rodents suggest a role of serotonin-3 receptor antagonism

Antidepressants often disrupt sleep. Vortioxetine, a multimodal antidepressant acting through serotonin (5-HT) transporter (SERT) inhibition, 5-HT3, 5-HT7 and 5-HT1D receptor antagonism, 5-HT1B receptor partial agonism, and 5-HT1A receptor agonism, had fewer incidences of sleep-related adverse events reported in depressed patients. In the accompanying paper a polysomnographic electroencephalography (sleep-EEG) study of vortioxetine and paroxetine in healthy subjects indicated that at low/intermediate levels of SERT occupancy, vortioxetine affected rapid eye movement (REM) sleep differently than paroxetine. Here we investigated clinically meaningful doses (80-90% SERT occupancy) of vortioxetine and paroxetine on sleep-EEG in rats to further elucidate the serotoninergic receptor mechanisms mediating this difference. Cortical EEG, electromyography (EMG), and locomotion were recorded telemetrically for 10 days, following an acute dose, from rats receiving vortioxetine-infused chow or paroxetine-infused water and respective controls. Sleep stages were manually scored into active wake, quiet wake, and non-REM or REM sleep. Acute paroxetine or vortioxetine delayed REM onset latency (ROL) and decreased REM episodes. After repeated administration, vortioxetine yielded normal sleep-wake rhythms while paroxetine continued to suppress REM. Paroxetine, unlike vortioxetine, increased transitions from non-REM to wake, suggesting fragmented sleep. Next, we investigated the role of 5-HT3 receptors in eliciting these differences. The 5-HT3 receptor antagonist ondansetron significantly reduced paroxetine's acute effects on ROL, while the 5-HT3 receptor agonist SR57227A significantly increased vortioxetine's acute effect on ROL. Overall, our data are consistent with the clinical findings that vortioxetine impacts REM sleep differently than paroxetine, and suggests a role for 5-HT3 receptor antagonism in mitigating these differences.

Effects of acute and sustained administration of vortioxetine on the serotonin system in the hippocampus: electrophysiological studies in the rat brain

RATIONALE

Vortioxetine is a novel multimodal antidepressant that is a 5-HT1B receptor partial agonist, a 5-HT1A receptor agonist, an inhibitor of the serotonin (5-HT) transporter, and a 5-HT1D, 5-HT3, and 5-HT7 receptor antagonist in vitro. In vivo studies have shown that vortioxetine enhances levels of 5-HT and desensitizes 5-HT1A autoreceptors.

OBJECTIVES

The aim of the present study was to investigate the effects of acute and long-term administration of vortioxetine on the terminal 5-HT1B receptor and the tonic activation of 5-HT1A receptor in the rat hippocampus.

METHODS

These receptors were assessed following vortioxetine administration acutely or subcutaneously using minipumps for 14 days. These studies were carried out using in vivo electrophysiological recording, microiontophoresis, and stimulation of the ascending 5-HT fibers.

RESULTS

Vortioxetine enhanced the inhibitory effect of the stimulation of the 5-HT bundle at a high, but not low frequency and reversed the inhibitory effect of the 5-HT1B receptor agonist CP 94253. These results indicate that this compound acted as a 5-HT1B receptor partial agonist. Vortioxetine inhibited 5-HT reuptake but did not dampen the sensitivity of postsynaptic 5-HT1A receptors on pyramidal neurons. Long-term administration of vortioxetine and escitalopram (both at 5 mg/kg/day) induced an increase of tonic activation of the 5-HT1A receptors in CA3 pyramidal neurons, resulting in an increase in 5-HT transmission. In addition, vortioxetine decreased the function of terminal 5-HT1B autoreceptor following its sustained administration.

CONCLUSIONS

Desensitization of 5-HT1B autoreceptor and an increase of tonic activation of 5-HT1A receptors in the hippocampus may contribute to the antidepressant effect of vortioxetine.

Vortioxetine : a review of efficacy, safety and tolerability with a focus on cognitive symptoms in major depressive disorder

INTRODUCTION

Vortioxetine is a pharmacodynamically novel antidepressant that exerts effects on various neurotransmitters including serotonin, noradrenaline, dopamine, glutamate, histamine and acetylcholine. Its efficacy in the symptomatic management of major depressive disorder (MDD) has been established in several short- and long-term trials. Vortioxetine has also demonstrated independent pro-cognitive effects in adults with MDD.

AREAS COVERED

This report provides a concise review of the pharmacology, efficacy and safety of vortioxetine as they pertain to cognition.

EXPERT OPINION

The significant impact of cognitive dysfunction in MDD has achieved increased consideration among researchers over the past decade. Vortioxetine is the first antidepressant agent to demonstrate meaningful clinical efficacy in the improvement of cognition in adults with MDD, independent of improvement in affective symptomatology. These results provide the impetus for further study into the potential pro-cognitive effects of vortioxetine in other conditions wherein cognitive dysfunction is prominent.

Vortioxetine, a multimodal antidepressant for generalized anxiety disorder: a systematic review and meta-analysis

Vortioxetine has a beneficial pharmacological profile for reducing anxiety and depression. Recently, a number of randomized, double-blind, placebo-controlled clinical trials (RCTs) of vortioxetine have been conducted in patients with generalized anxiety disorder (GAD); however, the results from GAD RCTs are inconsistent. With an extensive search of databases and clinical trial registries, four published short-term RCTs were identified and included in the present meta-analysis. The mean change in total scores on the Hamilton Anxiety Rating Scale (HAMA) from baseline was the primary endpoint. The secondary endpoints included the response and remission rates, as defined by a ≥50% reduction in HAMA total scores and a ≤7 change in the HAMA total score at the end of treatment. In addition, the mean change in the HAMA total score from baseline in the subgroup with a HAMA total score ≥25 at baseline was included. Vortioxetine was significantly more effective than was placebo, with a standardized mean difference (SMD) of -0.118 (95% CIs, -0.203 to -0.033, P = 0.007). In particular, those with severe GAD (HAMA total score ≥25 at baseline) had a significantly greater benefit from vortioxetine than those without (SMD = -0.338, 95% CIs = -0.552 to -0.124, p = 0.002). The odds ratios (ORs) for vortioxetine for response and remission were 1.221 (95% CIs, 1.027 to 1.452, P = 0.024) and 1.052 (95% CIs, 0.853 to 1.296, P = 0.637), respectively. Discontinuation due to adverse events (AEs) (OR = 1.560, 1.006 to 2.419, p = 0.047) was marginally higher in vortioxetine than placebo treatment, whereas discontinuation due to any reason (OR = 0.971, 0.794 to 1.187, p = 0.771) and inefficacy (OR = 0.687, 0.380 to 1.243, p = 0.215) were not significantly different among treatment groups. Although our results suggest that vortioxetine may have a potential as an another treatment option for GAD (especially for severe GAD), they should be interpreted and translated into clinical practice with caution, as the meta-analysis was based on a limited number of RCTs.

Modes and nodes explain the mechanism of action of vortioxetine, a multimodal agent (MMA): enhancing serotonin release by combining serotonin (5HT) transporter inhibition with actions at 5HT receptors (5HT1A, 5HT1B, 5HT1D, 5HT7 receptors)

Vortioxetine is an antidepressant that targets multiple pharmacologic modes of action at sites--or nodes--where serotonergic neurons connect to various brain circuits. These multimodal pharmacologic actions of vortioxetine lead to enhanced release of various neurotransmitters, including serotonin, at various nodes within neuronal networks.

Vortioxetine in the treatment of major depressive disorder

ABSTRACT 

Vortioxetine is a novel psychotropic drug, with evidence of efficacy in acute treatment of major depressive episodes and in prevention of relapse in major depressive disorder. It has been described as having a ‘multimodal’ serotonergic mechanism of action, involving reuptake inhibition and a range of effects on presynaptic and postsynaptic receptors. It also has important effects on other neurotransmitters thought to be important in the neurobiology of depression and response to antidepressant treatment. It is efficacious in reducing anxiety symptom severity in depressed patients. The tolerability profile of vortioxetine appears predictable from its pharmacological properties. It may have beneficial effects in improving ‘cognition’ in depression, and a lower incidence of treatment-emergent sexual dysfunction, but these potential benefits require further investigation.

The efficacy of vortioxetine for the treatment of major depressive disorder

Vortioxetine (Lu AA21004; Brintellix(®)) has received approval from various international regulatory agencies for the treatment of major depression. The drug molecule has a multimodal mechanism of action that projects it as a unique molecule for the treatment of major depression. These mechanisms include property to inhibit serotonin reuptake via inhibiting serotonin transporters and acting on multiple serotonin receptor subtypes. Vortioxetine is an agonist of 5-HT1A, a partial agonist of 5-HT1B and an antagonist of 5-HT1D, 5-HT3 and 5-HT7 serotoninergic receptors. The molecule has been found to be effective and well-tolerable to be administered in humans for the treatment of major depression. Precautions should be exercised when vortioxetine is prescribed with cytochrome P450 inducers and inhibitors. This review attempts to compile the efficacy profile of vortioxetine in different clinical trials and the results are compared with other standard antidepressants.

Vortioxetine restores reversal learning impaired by 5-HT depletion or chronic intermittent cold stress in rats

Current treatments for depression, including serotonin-specific reuptake inhibitors (SSRIs), are only partially effective, with a high incidence of residual symptoms, relapse, and treatment resistance. Loss of cognitive flexibility, a component of depression, is associated with dysregulation of the prefrontal cortex. Reversal learning, a form of cognitive flexibility, is impaired by chronic stress, a risk factor for depression, and the stress-induced impairment in reversal learning is sensitive to chronic SSRI treatment, and is mimicked by serotonin (5-HT) depletion. Vortioxetine, a novel, multimodal-acting antidepressant, is a 5-HT3, 5-HT7 and 5-HT1D receptor antagonist, a 5-HT1B receptor partial agonist, a 5-HT1A receptor agonist, and inhibits the 5-HT transporter. Using adult male rats, we first investigated the direct effects of vortioxetine, acting at post-synaptic 5-HT receptors, on reversal learning that was compromised by 5-HT depletion using 4-chloro-DL-phenylalanine methyl ester hydrochloride (PCPA), effectively eliminating any contribution of 5-HT reuptake blockade. PCPA induced a reversal learning impairment that was alleviated by acute or sub-chronic vortioxetine administration, suggesting that post-synaptic 5-HT receptor activation contributes to the effects of vortioxetine. We then investigated the effects of chronic dietary administration of vortioxetine on reversal learning that had been compromised in intact animals exposed to chronic intermittent cold (CIC) stress, to assess vortioxetine's total pharmacological effect. CIC stress impaired reversal learning, and chronic vortioxetine administration prevented the reversal-learning deficit. Together, these results suggest that the direct effect of vortioxetine at 5-HT receptors may contribute to positive effects on cognitive flexibility deficits, and may enhance the effect of 5-HT reuptake blockade.

A randomised, double-blind study in adults with major depressive disorder with an inadequate response to a single course of selective serotonin reuptake inhibitor or serotonin-noradrenaline reuptake inhibitor treatment switched to vortioxetine or agomelatine

OBJECTIVE

This randomised, double-blind, 12-week study compared efficacy and tolerability of flexible-dose treatment with vortioxetine(10-20 mg/day) versus agomelatine (25-50 mg/day) in major depressive disorder patients with inadequate response to selective serotonin reuptake inhibitor (SSRI)/serotonin-noradrenaline reuptake inhibitor (SNRI) monotherapy.

METHODS

Patients were switched directly from SSRI/SNRI to vortioxetine or agomelatine. Primary endpoint was change from baseline to week 8 in the Montgomery-Åsberg Depression Rating Scale (MADRS) total score analysed by mixed model for repeated measurements, using a noninferiority test followed by a superiority test. Secondary endpoints included response and remission rates, anxiety symptoms(Hamilton Anxiety Rating Scale), Clinical Global Impression, overall functioning (Sheehan Disability Scale), health-related quality of life(EuroQol 5 Dimensions), productivity (work limitation questionnaire) and family functioning (Depression and Family Functioning Scale).

RESULTS

Primary endpoint noninferiority was established and vortioxetine (n = 252) was superior to agomelatine (n = 241) by 2.2 MADRS points (p<0.01). Vortioxetine was also significantly superior in response and remission rates at weeks 8 and 12; MADRS, Hamilton Anxiety Rating Scale, Clinical Global Impression, Sheehan Disability Scale and EuroQol 5 Dimensions scores at week 4 onwards; work limitation questionnaire at week 8 and Depression and Family Functioning Scale at weeks 8 and 12. Fewer patients withdrew because of adverse events with vortioxetine (5.9% vs 9.5%). Adverse events (incidence ≥5%) were nausea, headache, dizziness and somnolence.

CONCLUSIONS

Vortioxetine was noninferior and significantly superior to agomelatine in major depressive disorder patients with previous inadequate response to a single course of SSRI/SNRI monotherapy. Vortioxetine was safe and well tolerated.

Vortioxetine: a review of its use in major depressive disorder

Vortioxetine (Brintellix(®)) is a serotonin (5-HT) transporter inhibitor that also acts on several 5-HT receptors, such as the 5-HT3 and 5-HT1A receptors. It is approved in the US and the EU for the treatment of adult patients with major depressive disorder (MDD); this article reviews the pharmacological properties of oral vortioxetine and its clinical efficacy and tolerability in these patients. Vortioxetine is generally efficacious in patients with MDD in acute treatment trials (including elderly patients), in a relapse-prevention trial, and in open-label extension trials. It is associated with improved cognitive function in patients with MDD; this does not occur solely via improvement in depressive symptom severity. It is well tolerated, but is associated with significantly increased sexual dysfunction at the highest dosage; however, vortioxetine was shown to improve previous-treatment-emergent sexual dysfunction in patients with well-treated MDD to a greater degree than escitalopram. Vortioxetine extends the available treatment options for patients with MDD, and further investigation into its comparative efficacy versus other antidepressants will allow for more accurate placement among these treatment options.

Reduced 5-HT(1B) receptor binding in the dorsal brain stem after cognitive behavioural therapy of major depressive disorder

Major depression is a significant contributor to the global burden of disease, and its pathophysiology is largely unknown. The serotonin hypothesis is, however, the model with most supporting data, although the details are only worked out to some extent. Recent clinical imaging measurements indeed imply a role in major depressive disorder (MDD) for the inhibitory serotonin autoreceptor 5-hydroxytryptamine1B (5-HT1B). The aim of the current study was to examine 5-HT1B receptor binding in the brain of MDD patients before and after psychotherapy. Ten patients with an ongoing untreated moderate depressive episode were examined with positron emission tomography (PET) and the 5-HT1B receptor selective radioligand [(11)C]AZ10419369, before and after treatment with internet-based cognitive behavioural therapy. All of the patients examined responded to treatment, and 70% were in remission by the time of the second PET measurement. A statistically significant 33% reduction of binding potential (BPND) was found in the dorsal brain stem (DBS) after treatment. No other significant changes in BPND were found. The DBS contains the raphe nuclei, which regulate the serotonin system. This study gives support for the importance of serotonin and the 5-HT1B receptor in the biological response to psychological treatment of MDD.

The role of molecular imaging in modern drug development

Drug development represents a highly complex, inefficient and costly process. Over the past decade, the widespread use of nuclear imaging, owing to its functional and molecular nature, has proven to be a determinant in improving the efficiency in selecting the candidate drugs that should either be abandoned or moved forward into clinical trials. This helps not only with the development of safer and effective drugs but also with the shortening of time-to-market. The modern concept and future trends concerning molecular imaging will assumedly be hybrid or multimodality imaging, including combinations between high sensitivity and functional (molecular) modalities with high spatial resolution and morphological techniques.

Vortioxetine for major depressive disorder: a systematic review of the efficacy and safety profile for this newly approved antidepressant - what is the number needed to treat, number needed to harm and likelihood to be helped or harmed?

OBJECTIVE

To describe the efficacy and safety of vortioxetine for the treatment of major depressive disorder (MDD).

DATA SOURCES

The pivotal registration trials were accessed by querying http://www.ncbi.nlm.nih.gov/pubmed/, http://www.clinicaltrialsregister.eu and http://www.clinicaltrials.gov for the search terms 'vortioxetine' and 'Lu AA21004', and by obtaining posters presented at congresses. Product labelling provided additional information.

STUDY SELECTION

All available clinical reports of studies were identified.

DATA EXTRACTION

Descriptions of the principal results and calculation of number needed to treat (NNT) and number needed to harm (NNH) for relevant dichotomous outcomes were extracted from the available study reports and other sources of information.

DATA SYNTHESIS

Vortioxetine is a multi-modal antidepressant that functions as a human 5-HT3A and 5-HT7 receptor antagonist, 5-HT1B receptor partial agonist, 5-HT1A receptor agonist, and inhibitor of the serotonin transporter. The recommended dose range is 5-20 mg/day. Approval for the treatment of MDD was based on a clinical development programme that included six positive 6-8 week studies, including one study in elderly people, and one positive maintenance study in adults. In the informative short-term studies in non-elderly patients, NNT for response with vortioxetine vs. placebo was 7 (95% CI 6-9), and NNT for remission vs. placebo was 11 (95% CI 8-17). NNH for discontinuation because of an adverse event (AE) was 36 (95% CI 24-70). The most commonly encountered AEs (incidence ≥ 5% and at least twice the rate of placebo) as identified in product labelling were nausea, constipation and vomiting, with NNH values vs. placebo of 6 (95% CI 6-7), 64 (95% CI 37-240), and 28 (95% CI 23-38), respectively. Changes in weight were not clinically relevant.

CONCLUSIONS

Vortioxetine represents another option for the treatment of MDD. Vortioxetine appears to have a favourable weight-gain profile. Additional information regarding the time course of response/remission and for the commonly occurring AE of nausea would be helpful to better characterise this agent. Pending clinical trials include those examining cognitive dysfunction that can accompany MDD.