Pfizer Inc. announced that a Phase 4 study evaluating the efficacy of PRISTIQ(R) (desvenlafaxine) Extended Release Tablets met its primary endpoint. The study supports the efficacy of 50 mg/day and 100 mg/day doses of PRISTIQ compared with placebo over eight weeks of treatment in adult patients with major depressive disorder (MDD) as measured by the 17-item Hamilton Rating Scale for Depression (HAM-D17) total score. In this study, the most common treatment-emergent adverse events observed were consistent with the known safety and tolerability profile of PRISTIQ.

The Phase 4 study was designed as a multi-center, randomized, double-blind, placebo-controlled, eight-week, parallel group study in adult patients with MDD.(1) The primary efficacy endpoint was the change from baseline in HAM-D17 total score at week eight. The HAM-D17 is a validated assessment tool used to rate the severity of a patient's major depressive symptoms.(2) The study enrolled 924 patients who were randomized in a 1:1:1 ratio to one of the following treatment arms: PRISTIQ 50 mg/day, PRISTIQ 100 mg/day or placebo. Results from this PRISTIQ Phase 4 study will be submitted for presentation at upcoming scientific congresses and for publication in a peer-reviewed medical journal.