Pharmacotherapeutic group: Psychoanaleptics; Other antidepressants, ATC code: N06AX26
Mechanism of action
The mechanism of action of vortioxetine is thought to be related to its direct modulation of serotonergic receptor activity and inhibition of the serotonin (5-HT) transporter. Nonclinical data indicate that vortioxetine is a 5-HT3, 5-HT7, and 5-HT1D receptor antagonist, 5-HT1B receptor partial agonist, 5-HT1A receptor agonist and inhibitor of the 5-HT transporter, leading to modulation of neurotransmission in several systems, including predominantly the serotonin but probably also the norepinephrine, dopamine, histamine, acetylcholine, GABA and glutamate systems. This multimodal activity is considered responsible for the antidepressant and anxiolytic-like effects and the improvement of cognitive function, learning and memory observed with vortioxetine in animal studies. However, the precise contribution of the individual targets to the observed pharmacodynamic profile remains unclear and caution should be applied when extrapolating animal data directly to man.
In humans, two positron emission tomography (PET) studies have been conducted using 5-HT transporter ligands (11C-MADAM or 11C-DASB) to quantify the 5-HT transporter occupancy in the brain across different dose levels. The mean 5-HT transporter occupancy in the raphe nuclei was approximately 50% at 5 mg/day, 65% at 10 mg/day and increased to above 80% at 20 mg/day.
Clinical efficacy and safety
The efficacy and safety of vortioxetine have been studied in a clinical programme that included more than 6,700 patients, of whom more than 3,700 were treated with vortioxetine in short-term (≤12 weeks) studies of major depressive disorder (MDD). Twelve double-blind, placebo controlled, 6/8-week, fixed-dose studies have been conducted to investigate the short-term efficacy of vortioxetine in MDD in adults (including the elderly). The efficacy of vortioxetine was demonstrated with at least one dosage group across 9 of the 12 studies, showing at least a 2-point difference to placebo in the Montgomery and Åsberg Depression Rating Scale (MADRS) or Hamilton Depression Rating Scale 24-item (HAM-D24) total score. This was supported by clinical relevance as demonstrated by the proportions of responders and remitters and the improvement in the Clinical Global Impression – Global Improvement (CGI-I) score. The efficacy of vortioxetine increased with increasing dose.
The effect in the individual studies was supported by the meta-analysis (MMRM) of the mean change from baseline in MADRS total score at Week 6/8 in the short-term, placebo-controlled studies in adults. In the meta-analysis, the overall mean difference to placebo across the studies was statistically significant: -2.3 points (p = 0.007), -3.6 points (p <0.001), and -4.6 points (p <0.001) for the 5, 10, and 20 mg/day doses, respectively; the 15 mg/day dose did not separate from placebo in the meta-analysis, but the mean difference to placebo was -2.6 points. The efficacy of vortioxetine is supported by the pooled responder analysis, in which the proportion of responders ranged from 46% to 49% for vortioxetine versus 34% for placebo (p <0.01; NRI analysis).
Furthermore, vortioxetine, in the dose range of 5-20 mg/day, demonstrated efficacy on the broad range of depressive symptoms (assessed by improvement in all MADRS single–item scores).
The efficacy of vortioxetine 10 or 20 mg/day was further demonstrated in a 12-week, double-blind, flexible-dose comparative study versus agomelatine 25 or 50 mg/day in patients with MDD. Vortioxetine was statistically significantly better than agomelatine as measured by improvement in the MADRS total score and supported by the clinical relevance as demonstrated by the proportions of responders and remitters and improvement in the CGI-I.
Maintenance
The maintenance of antidepressant efficacy was demonstrated in a relapse-prevention study. Patients in remission after an initial 12-week open-label treatment period with vortioxetine were randomised to vortioxetine 5 or 10 mg/day or placebo and observed for relapse during a double-blind period of at least 24 weeks (24 to 64 weeks). Vortioxetine was superior (p=0.004) to placebo on the primary outcome measure, the time to relapse of MDD, with a hazard ratio of 2.0; that is, the risk of relapse was two times higher in the placebo group than in the vortioxetine group.
Elderly
In the 8-week, double-blind, placebo-controlled, fixed-dose study in elderly depressed patients (aged ≥65 years, n=452, 156 of whom were on vortioxetine), vortioxetine 5 mg/day was superior to placebo as measured by improvement in the MADRS and HAM-D24 total scores. The effect seen with vortioxetine was a 4.7 point difference to placebo in MADRS total score at Week 8 (MMRM analysis).
Patients with severe depression or with depression and high levels of anxiety symptoms
In severely depressed patients (baseline MADRS total score ≥30) and in depressed patients with a high level of anxiety symptoms (baseline HAM-A total score ≥20) vortioxetine also demonstrated efficacy in the short-term studies in adults (the overall mean difference to placebo in MADRS total score at Week 6/8 ranged from 2.8 to 7.3 points and from 3.6 to 7.3 points, respectively,(MMRM analysis)). In the dedicated study in elderly, vortioxetine was also effective in these patients.
The maintenance of antidepressant efficacy was also demonstrated in this patient population in the long-term relapse prevention study.
Effects of vortioxetine on the Digit Symbol Substitution Test (DSST), the University of California San Diego Performance-Based Skills Assessment (UPSA) (objective measures) and Perceived Deficits Questionnaire (PDQ) and Cognitive and Physical Functioning Questionnaire CPFQ (subjective measures) scores
The efficacy of vortioxetine (5-20 mg/day) in patients with MDD has been investigated in 2 adult and 1 elderly short-term, placebo-controlled studies.
Vortioxetine had a statistically significant effect versus placebo on the Digit Symbol Substitution Test (DSST), ranging from Δ = 1.75 (p = 0.019) to 4.26 (p <0.0001) in the 2 studies in adults and Δ = 2.79 (p = 0.023) in the study in the elderly. In the meta-analyses (ANCOVA, LOCF) of the mean change from baseline in DSST number of correct symbols in all 3 studies, vortioxetine separated from placebo (p<0.05) with a standardised effect size of 0.35. When adjusting for the change in MADRS the total score in the meta-analysis of the same studies showed that vortioxetine separated from placebo (p<0.05) with a standardised effect size of 0.24.
One study assessed the effect of vortioxetine on functional capacity using the University of California San Diego Performance-Based Skills Assessment (UPSA). Vortioxetine separated from placebo statistically with results of 8.0 for vortioxetine versus 5.1 points for placebo (p=0.0003).
In one study, vortioxetine was superior to placebo on subjective measures, evaluated using the Perceived Deficits Questionnaire with results of -14.6 for vortioxetine and -10.5 for placebo (p=0.002). Vortioxetine did not separate from placebo on subjective measures when evaluated using the Cognitive and Physical Functioning Questionnaire with results of -8.1 for vortioxetine versus -6.9 for placebo (p=0.086).
Tolerability and safety
The safety and tolerability of vortioxetine have been established in short- and long-term studies across the dose range of 5 to 20 mg/day. For information on undesirable effects, see section 4.8.
Vortioxetine did not increase the incidence of insomnia or somnolence relative to placebo.
In clinical short- and long-term placebo-controlled studies, potential discontinuation symptoms were systematically evaluated after abrupt treatment cessation of vortioxetine. There was no clinically relevant difference to placebo in the incidence or nature of the discontinuation symptoms after either short-term (6-12 weeks) or long-term (24-64 weeks) treatment with vortioxetine.
The incidence of self-reported adverse sexual reactions was low and similar to placebo in clinical short- and long-term studies with vortioxetine. In studies using the Arizona Sexual Experience Scale (ASEX), the incidence of treatment-emergent sexual dysfunction (TESD) and the ASEX total score showed no clinically relevant difference to placebo in symptoms of sexual dysfunction at the 5 to 15 mg/day doses of vortioxetine. For the 20 mg/day dose, an increase in TESD was seen compared to placebo (an incidence difference of 14.2%, 95% CI [1.4, 27.0]).
The effect of vortioxetine on sexual function was further evaluated in an 8-week, double-blind, flexible-dose, comparative study (n=424) versus escitalopram in patients treated for at least 6 weeks with an SSRI (citalopram, paroxetine, or sertraline), with a low level of depressive symptoms (baseline CGI-S ≤ 3) and TESD induced by the prior SSRI treatment. Vortioxetine 10-20 mg/day had statistically significantly less TESD than escitalopram 10-20 mg/day as measured by change in the CSFQ-14 total score (2.2 points, p=0.013) at week 8. The proportion of responders was not significantly different in the vortioxetine group (162 (74.7%)) compared with the escitalopram group (137 (66.2%)) at week 8 (OR 1.5 p=0.057). The antidepressant effect was maintained in both treatment groups.
Vortioxetine had no effect relative to placebo on body weight, heart rate, or blood pressure in clinical short- and long-term studies.
No clinically significant changes were observed in hepatic or renal assessments in clinical studies.
Vortioxetine has not shown any clinically significant effect on ECG parameters, including the QT, QTc, PR and QRS intervals, in patients with MDD. In a thorough QTc study in healthy subjects at doses up to 40 mg daily, no potential for the prolongation of the QTc interval was observed.
Paediatric population
Two short-term, randomised, double-blind, placebo-controlled, fixed-dose (vortioxetine 10 mg/day and 20 mg/day), active-referenced (fluoxetine), efficacy and safety studies have been conducted; one in children aged 7 to 11 years with MDD, and one in adolescents aged 12 to 17 years with MDD. The studies included a 4-week single-blind placebo lead-in period with standardized psychosocial intervention (treated patients in children study N=677, adolescent study N=777) and only non-responders from the lead-in period were randomised (children study N=540, adolescent study N=616).
In the study in children aged 7 to 11 years, the average effect of the two vortioxetine doses 10 and 20 mg/day was not statistically significantly different from placebo based on the Children´s Depression Rating Scale-Revised (CDRS-R) total score at week 8, nor was the active reference (fluoxetine 20 mg/day), nor did the individual vortioxetine doses (10 and 20mg/day) show a nominally significant difference from placebo. In general, the adverse event profile of vortioxetine in children was similar to that seen for adults, except for higher incidence of abdominal pain reported in children. Discontinuation due to adverse events was 2.0% in patients treated with vortioxetine 20 mg/day, 1.3% for vortioxetine 10 mg/day, 0.7% for placebo, and no discontinuations for fluoxetine. The most commonly reported adverse events in the vortioxetine treatment groups were nausea, headache, vomiting, dizziness, and abdominal pain. The incidence of nausea, vomiting and abdominal pain was higher in the vortioxetine groups than in the placebo group. Suicidal ideation and behaviour were reported as adverse events during the 4-week single-blind lead-in period (placebo 2/677 [0.3%]), and during the 8-week treatment period (vortioxetine 10 mg/day 1/149 [0.7%], placebo 1/153 [0.7%]). In addition, the event 'non-specific active suicidal thoughts' was reported in the C-SSRS in 5 patients during the 8-week treatment period (vortioxetine 20 mg/day 1/153 [0.7%], placebo 1/153 [0.7%] and fluoxetine 3/82 [3.7%]). Suicidal ideation and behaviour as measured by Columbia-Suicide Severity Rating Scale (C-SSRS) was similar across treatment groups.
In the study in adolescents aged 12 to 17 years neither vortioxetine 10 mg/day nor 20 mg/day was statistically significantly superior to placebo based on the Children´s Depression Rating Scale-Revised (CDRS-R) total score. The active reference (fluoxetine 20 mg/day) separated statistically from placebo on the CDRS-R total score. In general, the adverse reaction profile of vortioxetine in adolescents was similar to that seen for adults except for higher incidences reported in adolescents than in adults for abdominal pain and suicidal ideation. Discontinuation due to adverse events (mostly due to suicidal ideation, nausea and vomiting) was highest in patients treated with vortioxetine 20 mg/day (5.6%) as compared to vortioxetine 10 mg/day (2.7%), fluoxetine (3.3%), and placebo (1.3%). The most commonly reported adverse events in the vortioxetine treatment groups were nausea, vomiting and headache. Suicidal ideation and behaviour were reported as adverse events both during the 4-week single-blind lead-in period (placebo 13/777 [1.7%]), and during the 8-week treatment period (vortioxetine 10 mg/day 2/147 [1.4%], vortioxetine 20 mg/day 6/161 [3.7%], fluoxetine 6/153 [3.9%], placebo 0/154 [0%]). Suicidal ideation and behaviour as measured by C-SSRS was similar across treatment groups.
Brintellix should not be used in paediatric patients (under 18 years of age) with major depressive disorder (see section 4.2).
The licensing authority has waived the obligation to submit the results of studies in major depressive disorder with vortioxetine in children aged less than 7 years (see section 4.2 for information on paediatric use).