A pooled analysis of two placebo-controlled trials of desvenlafaxine in major depressive disorder

The efficacy, safety, and tolerability of desvenlafaxine (administered as desvenlafaxine succinate) were evaluated in two similarly designed, phase 3, randomized, double-blind, placebo-controlled, venlafaxine-extended-release-referenced, flexible-dose studies of outpatients with a primary diagnosis of major depressive disorder. Owing to a high placebo response, the individual studies were underpowered. Therefore, a post-hoc pooled analysis was performed (desvenlafaxine and placebo data were pooled; venlafaxine extended release data were not, owing to different flexible-dose regimens in the two studies). The primary outcome measure was the change from baseline on the 17-item Hamilton Rating Scale for Depression; the Clinical Global Impressions-Improvement item score was a secondary outcome. Analysis of the pooled data (using a mixed-effect model for repeated measures) revealed that after 8 weeks of treatment, desvenlafaxine was significantly better than placebo on 17-item Hamilton Rating Scale for Depression [−14.21 vs. −11.87 for desvenlafaxine and placebo, respectively; magnitude of effect=−2.34 (P<0.001)] and Clinical Global Impressions-Improvement item scores [1.95 vs. 2.32 for desvenlafaxine and placebo, respectively; magnitude of effect=−0.37 (P<0.001)]. Adverse events were comparable to those found with other drugs sharing a similar mechanism of action. These data support the efficacy, safety, and tolerability of desvenlafaxine in the treatment of major depressive disorder.