New Study Results Provide Additional Data about Short- and Long-Term Use of Desvenlafaxine Succinate in the Treatment of Adults with Major Depressive Disorder

Collegeville, Pa.— Data from four new studies examining safety and efficacy of desvenlafaxine succinate, a serotonin-norepinephrine reuptake inhibitor (SNRI) being studied as a potential treatment for adults with major depressive disorder (MDD), were presented today at the 2007 American Psychiatric Association annual meeting in San Diego, Calif., by Wyeth Pharmaceuticals, a division of Wyeth (NYSE:WYE). Results from short-term studies and a six-month relapse prevention study showed that desvenlafaxine succinate improved symptoms of MDD vs. placebo in adult patients with depression. In addition, results from a 12-month safety study were presented.

“Depression is a chronic condition where a large number of treated patients often experience a relapse or a return of symptoms following a positive response to treatment,” says Philip Ninan, M.D., Vice President, Neuroscience, Global Medical Affairs for Wyeth Pharmaceuticals. “We are encouraged by these clinical trials, which show that desvenlafaxine, if approved, may be an important option for the treatment of adult patients with major depressive disorder.”

About the Studies
Poster NR327: Rickels K, et al. A Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study of Desvenlafaxine Succinate for Prevention of Depressive Relapse in Adult Outpatients with Major Depressive Disorder

Study findings from the double-blind phase showed that patients who took desvenlafaxine succinate experienced a significantly longer time to relapse of MDD compared with patients who took placebo. The study also found that more patients who took desvenlafaxine succinate achieved remission (Hamilton Rating Scale for Depression [HAM-D17] score of 7) by Week 4 of the study than those in the placebo group. The most frequent cause for discontinuation of treatment in the double-blind study was depression, reported by 4 percent of patients who took desvenlafaxine succinate and 8 percent of placebo patients. The most frequent adverse events with desvenlafaxine succinate in the double-blind phase included headache, nausea, dizziness, asthenia, abnormal dreams and sweating.

The double-blind study population included 375 adults, 18 to 75 years old, with a primary diagnosis of MDD who participated in an initial 12-week, open-label study of desvenlafaxine succinate at doses ranging from 200 to 400 mg/day (desvenlafaxine succinate group, n=190; placebo group, n=185). The primary efficacy endpoint in the double-blind phase of the study was time until relapse, defined by a HAM-D17 score 16 at any visit; Clinical Global Impressions Scale – Improvement score 6 at any visit; or discontinuation due to unsatisfactory response. The study also assessed the response and remission of desvenlafaxine succinate vs. placebo as a secondary objective.

Poster NR344: Ferguson J, et al. A 12-Month, Open-Label Evaluation of Long-Term Safety and Efficacy of Desvenlafaxine Succinate in Outpatients with Major Depressive Disorder

The results are from a Phase 3, multicenter, open-label, flexible-dose study. This study included 104 adults, 18 to 75 years old, with a primary diagnosis of MDD who took doses of desvenlafaxine succinate ranging from 200 to 400 mg/day over a 12-month period. The primary objective was to evaluate the long-term safety of desvenlafaxine succinate as determined by monitoring a variety of indices, including adverse events, patient discontinuation due to adverse events, electrocardiograms, vital signs and the results of laboratory tests. The secondary objective was to evaluate the efficacy of desvenlafaxine succinate by using mean HAM-D17 total scores.

Study findings showed that the most frequent treatment-emergent adverse events were nausea and headache. Nausea generally was transient, usually resolving within the first week. Nine patients (9 percent) had hypertension during the trial. Six patients reported a serious adverse event, none of which was considered related to desvenlafaxine succinate. Adverse events were noted as the cause of discontinuation from the study in about one-third of patients — with the majority of discontinuations occurring in the first week. Study findings also showed that HAM-D17 mean total scores steadily decreased from baseline at Day 7 through Day 60 and continued to decrease through the end of the study.

Poster NR363: Ahmed S, et al. Switch from Venlafaxine to Desvenlafaxine Succinate Is Well-Tolerated in Patients with Major Depressive Disorder

In this study, patients taking venlafaxine ER were able to transition to desvenlafaxine succinate with a lower incidence of nausea than patients who switched from placebo to 200 mg/day of desvenlafaxine succinate. Furthermore, patients who switched from venlafaxine ER to desvenlafaxine succinate and those who remained on desvenlafaxine succinate were less likely to discontinue therapy than patients who switched from placebo to 200 mg/day of desvenlafaxine succinate (without titration).

Before joining the 10-week, open-label study, 517 patients completed one of two eight-week, double-blind, placebo-controlled, flexible-dose studies of desvenlafaxine succinate and venlafaxine ER. Patients who received either placebo (n=186) or venlafaxine ER (n=183) during the double-blind study began the open-label phase at 200 mg/day of desvenlafaxine succinate, while patients who took desvenlafaxine succinate (n=148) during the double-blind study remained on the same dose at the beginning of the open-label study. Based on clinical response, each patient’s dose of desvenlafaxine succinate could be adjusted during the open-label study.

Study findings show that overall treatment-emergent adverse events reported during the 10-week study were similar for all treatment groups — 91 percent reported at least one adverse event in the placebo/desvenlafaxine succinate group; 86 percent in the venlafaxine ER/desvenlafaxine succinate group; and 86 percent in the desvenlafaxine succinate/desvenlafaxine succinate group. The incidence of nausea was highest for the placebo/desvenlafaxine succinate group during the first week of treatment and decreased to rates similar to the venlafaxine ER/desvenlafaxine succinate group (p= 0.03) and the desvenlafaxine succinate/desvenlafaxine succinate group at Day 8 and beyond. Additionally, discontinuation rates due to adverse events were highest in the placebo/desvenlafaxine succinate group and lowest in the desvenlafaxine succinate/desvenlafaxine succinate group (placebo/desvenlafaxine succinate: 23 percent; venlafaxine ER/desvenlafaxine succinate: 16 percent; desvenlafaxine succinate/desvenlafaxine succinate: 11 percent).

Poster NR299: Feiger AD, et al. A Placebo-Controlled Efficacy and Safety Study of a Flexible Dose of Desvenlafaxine Succinate in Outpatients with Major Depressive Disorder

According to the results of a Phase 3, multicenter, double-blind, placebo-controlled, parallel-group, flexible-dose study, there was no significant difference between patients receiving placebo and those receiving desvenlafaxine succinate based on the primary endpoint of change from baseline in the HAM-D17 total score at the final evaluation of Week 8, using analysis of co-variance with last-observation-carried-forward (LOCF) analyses. However, based on observed-cases analysis of the primary endpoint, there was a significant difference at Week 8 between patients who took desvenlafaxine succinate vs. patients receiving placebo. Based on LOCF and observed-case analysis of various secondary endpoints, desvenlafaxine succinate was significantly better than placebo.

Patients in this study were randomized to receive desvenlafaxine succinate 200 to 400 mg/day (n=117) or placebo (n=118). Significantly more patients in the desvenlafaxine succinate group responded to treatment compared with the placebo group (51 percent vs. 32 percent, respectively) at the final study evaluation. When individual items from the HAM-D17 were analyzed, desvenlafaxine succinate patients experienced a statistically significant improvement in depressed mood, psychic anxiety, general somatic symptoms and suicidal thoughts. Treatment-emergent adverse events reported in this study were consistent with the SNRI class and included nausea, dry mouth, insomnia, somnolence, sweating, anorexia (loss of appetite), tremor and impotence.

About Desvenlafaxine
Desvenlafaxine is a serotonin-norepinephrine reuptake inhibitor (SNRI) studied as a potential treatment for adult men and women with MDD. Wyeth submitted a New Drug Application (NDA) for MDD on December 22, 2005. The Company also has filed an NDA for vasomotor symptoms (VMS) associated with menopause and expects a U.S. Food and Drug Administration (FDA) action letter in the third quarter of 2007. If approved, desvenlafaxine will be the first and only non-hormonal medicine for the treatment of VMS associated with menopause. Wyeth is a leader in both neuroscience and women’s health care.

Wyeth discovered and developed the first SNRI approved by the FDA, which currently is the most widely used antidepressant in the world. Desvenlafaxine represents Wyeth’s latest efforts and continued commitment to developing therapies to help improve the lives of patients suffering from mental health disorders.

According to a large depression trial funded by the National Institute of Mental Health, only 28 percent of patients with depression achieved remission with initial antidepressant treatment. This leaves a large percentage of patients still suffering from depression. Clearly, additional medicines are needed for treating MDD.

About Antidepressants
Antidepressants increased the risk of suicidal thinking and behavior (suicidality) in short-term studies in children and adolescents with major depressive disorder and other psychiatric disorders. Anyone considering the use of any antidepressant in a child or adolescent must balance this risk with the clinical need. Patients who are on such therapy should be observed closely for clinical worsening, suicidality or unusual changes in behavior. Families and caregivers should be advised of the need for close observation and communication with their prescriber.

About Major Depressive Disorder
Major depressive disorder is a serious medical condition that is different from “feeling blue” and is not something people just “get over.” Criteria for major depressive disorder include five or more of the following symptoms that have been present for at least two weeks, and at least one of the symptoms must be either depressed mood or loss of interest or pleasure.

* Depressed mood
* Loss of interest or pleasure
* Changes in appetite or weight
* Changes in sleeping patterns
* Psychomotor agitation or retardation
* Fatigue or low energy
* Feeling worthless or guilty for no reason
* Difficulty thinking or concentrating
* Thoughts of death or suicide

Further, people with major depressive disorder may experience clinically significant distress or impairment in social, occupational or other important areas of functioning. If a person experiences these symptoms, he or she should speak with a health care professional.

Major depressive disorder is a common mental disorder, affecting about 121 million people worldwide. In the United States, it is estimated that depression affects about 19 million American adults each year. The lifetime risk of major depression has been assessed from 10 percent to 25 percent for women and 5 percent to 12 percent for men. Research has shown that hormonal changes, including estrogen decline, or life stressors experienced by women may contribute to a major depressive episode.