Pfizer Posted Results from a Phase 3 Study Evaluating Desvenlafaxine Succinate

Pfizer Inc announced the top line results from a Phase 3 study which evaluated the efficacy, safety, and tolerability of Pristiq® (desvenlafaxine succinate sustained-release formulation) in pediatric patients ages 7 to 17 with Major Depressive Disorder (MDD).

The study did not meet its primary objective to demonstrate superior efficacy of desvenlafaxine succinate sustained-release formulation compared to placebo.

This is the first completed study of four Phase 3 pediatric trials being conducted as part of an FDA post-marketing commitment under the Pediatric Research Equity Act.

The study was a randomized, double-blind, placebo-controlled, fluoxetine-referenced study designed to evaluate the efficacy, safety, and tolerability of desvenlafaxine succinate sustained-release formulation in pediatric outpatients ages 7 to 17 with MDD. A total of 340 subjects were randomized. The patient population was comprised of 38.3 percent children (7-11 years of age) and 61.7 percent adolescents (12-17 years of age). This study included three treatment arms: desvenlafaxine succinate sustained-release formulation (weight-based dosing to achieve pediatric exposures approximating exposures in adults receiving 35 mg/day), fluoxetine (20 mg/day), and placebo.

Efficacy results indicate that both desvenlafaxine succinate sustained-release formulation and the positive control, fluoxetine, were not statistically significantly different from placebo.

There were no new safety signals identified. Adverse events occurring after the start of treatment in the desvenlafaxine succinate sustained-release formulation group were generally consistent with those observed in both the Phase 2a pediatric MDD safety studies and the studies of desvenlafaxine succinate sustained-release formulation-treated adults with MDD.

PRISTIQ, a selective serotonin and norepinephrine reuptake inhibitor (SNRI), is a prescription medication that was approved by the U.S. Food and Drug Administration (FDA) in 2008 for the treatment of MDD in adults. The recommended dose for PRISTIQ is 50 mg once daily, with or without food. In clinical studies, doses of 50-400 mg/day were shown to be effective, although no additional benefit was demonstrated at doses greater than 50 mg/day and adverse events and discontinuations were more frequent at higher doses.