Clinical utility of desvenlafaxine 50 mg/d for treating MDD: a review of two randomized placebo-controlled trials for the practicing physician.

BACKGROUND: Major depressive disorder (MDD) is a common, seriously impairing illness. Desvenlafaxine (administered as desvenlafaxine succinate) is the third serotonin-norepinephrine reuptake inhibitor (SNRI) approved in the United States for the treatment of MDD. Short-term clinical studies have demonstrated the efficacy and safety of 50 to 400 mg/d doses, with no evidence that doses greater than 50 mg/d confer additional benefit. OBJECTIVE: This paper summarizes published data on the efficacy, safety, and tolerability of the desvenlafaxine 50-mg/d recommended therapeutic dose for MDD and discusses clinical practice considerations. METHODS: A systematic review of MEDLINE, PsycINFO, and PubMed (all years through June 2009) was performed using the terms desvenlafaxine, DVS, and ODV. The criteria for inclusion in the review were a double-blind design, a placebo control or active comparator group, the 50-mg desvenlafaxine dose group, and enrollment of patients with a diagnosis of MDD. Posters were included if they reported on a study that was subsequently published in a manuscript. RESULTS: Overall results of two randomized, placebo-controlled, 8-week clinical trials demonstrated the efficacy of desvenlafaxine 50 mg/d for MDD. Statistically significant improvements compared with placebo were observed on the primary efficacy measure (17-item Hamilton Rating Scale for Depression [HAM-D(17)] total score; P < 0.05). Significant differences were observed on several secondary measures (Montgomery Asberg Depression Rating Scale scores in both trials [P < 0.05]; Clinical Global Impressions-Improvement scores [P < or = 0.01], Clinical Global Impressions-Severity scores [P < or = 0.01], HAM-D(17) response [P < or = 0.01] and remission [P < 0.05] in one trial each). Functional outcomes measures (Sheehan Disability Scale total and World Health Organization 5-Item Well-Being Index scores) were significant in both trials (P < 0.05). Safety results indicate desvenlafaxine treatment was safe and well tolerated; findings were consistent with the SNRI class. The generalizability of these findings is limited by the study protocols, which excluded patients with unstable comorbid medical conditions and also those with other Axis 1 and 2 psychiatric illnesses. Additionally, comparisons with other SNRIs are challenging given differences in study design. Desvenlafaxine can be initiated with the 50-mg/d therapeutic dose without titration and provides efficacy with rates of discontinuation due to treatment-emergent adverse events similar to placebo. In vitro data indicate desvenlafaxine has minimal inhibitory effects on cytochrome P450 (CYP) 2D6 and clinical studies show desvenlafaxine does not have a clinically relevant effect on CYP2D6 metabolism. In vitro data also indicate desvenlafaxine is not a substrate or inhibitor of the p-glycoprotein transporter. Plasma protein binding of desvenlafaxine is low (30%) and independent of drug concentration. Bioavailability is high at 80% after oral administration and is not affected by food. CONCLUSIONS: Desvenlafaxine 50 mg/d has demonstrated efficacy, safety, and tolerability for the treatment of MDD in two placebo-controlled trials. The metabolic profile of desvenlafaxine suggests a low risk of drug-drug interactions owing to minimal inhibitory effects on CYP2D6, lack of interaction with p-glycoprotein, and low protein binding. [ABSTRACT FROM AUTHOR]