Pharmacokinetics and Tolerability of Single-Ascending Doses of Desvenlafaxine Administered to Children and Adolescents with Major Depressive Disorder

A Review of Novel Antidepressants: A Guide for Clinicians

This review article aims to provide insight into the mechanisms of action, pharmacokinetics, clinical efficacy, safety and tolerability of four novel antidepressants including desvenlafaxine, vortioxetine, vilazodone, and levomilnacipran. Following keywords are used in PubMed and Scopus to search for relevant articles: (depression) AND (psychopharmacology OR desvenlafaxine OR levomilnacipran OR vortioxetine OR vilazodone). Patients with a lack of effectiveness or tolerability to certain antidepressants may get benefit from selecting a new antidepressant with different mechanism of action. These medications can be an option in the selection of newer antidepressants. Depression may not be caused by the simple deficiency of serotonin in the brain, but rather a complex interplay of various neurotransmitters including serotonin, norepinephrine, glutamate, and histamine at certain brain areas. The above-mentioned novel antidepressants exert their therapeutic benefits by acting on multiple neurotransmitters. The complexity of underlying the neurobiological mechanism should be considered while formulating a plan of care.

Desvenlafaxine Versus Placebo in the Treatment of Children and Adolescents with Major Depressive Disorder

OBJECTIVE

To evaluate the short-term efficacy and safety of desvenlafaxine versus placebo in the treatment of children and adolescents with major depressive disorder (MDD).

METHODS

Outpatient children (7-11 years) and adolescents (12-17 years) who met DSM-IV-TR criteria for MDD and had screening and baseline Children's Depression Rating Scale-Revised (CDRS-R) total scores >40 were randomly assigned to 8 weeks of treatment with placebo, low exposure desvenlafaxine (20, 30, or 35 mg/day based on baseline weight), or higher exposure desvenlafaxine (25, 35, or 50 mg/day based on baseline weight). The primary efficacy endpoint was change from baseline in CDRS-R total score at week 8, analyzed using a mixed-effects model for repeated measures. Secondary efficacy assessments included Clinical Global Impressions-Severity and Clinical Global Impressions-Improvement scales. Safety assessments included adverse events and the Columbia-Suicide Severity Rating Scale.

RESULTS

The safety population included 363 patients (children, n = 109; adolescents, n = 254). No statistical separation from placebo was observed for either desvenlafaxine group for CDRS-R total score or for any secondary efficacy endpoint. At week 8, adjusted mean (standard error) changes from baseline in CDRS-R total score for the desvenlafaxine low exposure, desvenlafaxine high exposure, and placebo groups were -23.7 (1.1), -24.4 (1.1), and -22.9 (1.1), respectively. The incidence of adverse events was similar among groups.

CONCLUSION

Low and high exposure desvenlafaxine groups did not demonstrate efficacy for the treatment of MDD in children and adolescents in this double-blind, placebo-controlled trial. Desvenlafaxine (20-50 mg/day) was generally safe and well tolerated with no new safety signals identified in pediatric patients with MDD in this study.

Desvenlafaxine Versus Placebo in a Fluoxetine-Referenced Study of Children and Adolescents with Major Depressive Disorder

OBJECTIVES

To evaluate the short-term efficacy and safety of desvenlafaxine (25-50 mg/d) compared with placebo in children and adolescents with major depressive disorder (MDD).

METHODS

Outpatient children (7-11 years) and adolescents (12-17 years) who met DSM-IV-TR criteria for MDD and had screening and baseline Children's Depression Rating Scale-Revised (CDRS-R) total scores >40 were randomly assigned to 8-week treatment with placebo, desvenlafaxine (25, 35, or 50 mg/d based on baseline weight), or fluoxetine (20 mg/d). The primary efficacy endpoint was change from baseline in CDRS-R total score at week 8, analyzed using a mixed-effects model for repeated measures. Secondary efficacy endpoints included week 8 Clinical Global Impressions-Severity, Clinical Global Impressions-Improvement (CGI-I), and response (CGI-I ≤ 2). Safety assessments included adverse events, physical and vital sign measurements, laboratory evaluations, electrocardiogram, and the Columbia-Suicide Severity Rating Scale.

RESULTS

The safety population included 339 patients (children, n = 130; adolescents, n = 209). The primary endpoint, change from baseline in CDRS-R total score at week 8, did not statistically separate from placebo, for either desvenlafaxine (adjusted mean [standard error] change, -22.6 [1.17]) or fluoxetine (-24.8 [1.17]; placebo, -23.1 [1.18]). Week 8 CGI-I response rates were significantly greater for fluoxetine (78.2%; p = 0.017) than for placebo (62.6%); desvenlafaxine (68.7%) did not differ from placebo. Other secondary outcomes were consistent with those obtained with CDRS-R. Rates of treatment-emergent adverse events were comparable among treatment groups (desvenlafaxine, 60.0%; placebo, 70.5%; and fluoxetine, 64.3%).

CONCLUSION

Desvenlafaxine did not demonstrate efficacy for treating MDD in children and adolescents in this trial. Because neither desvenlafaxine nor the reference medication, fluoxetine, demonstrated a statistically significant difference from placebo on the primary endpoint, this was considered a failed trial and no efficacy conclusions can be drawn. Desvenlafaxine 25-50 mg/d was generally safe and well tolerated in children and adolescents in this study.