Wyeth Presents Phase 3 Data for Pristiq, an Investigational Non-Hormonal Therapy for Menopausal Hot Flashes and Night Sweats

COLLEGEVILLE, Pa., May 9 /PRNewswire-FirstCall/ -- Wyeth Pharmaceuticals, a division of Wyeth , presented results from the first Phase 3 studies evaluating Pristiq(TM) (desvenlafaxine) for the treatment of moderate-to-severe vasomotor symptoms (hot flashes and night sweats) associated with menopause. These studies showed that women who took Pristiq experienced a reduction in both the number and severity of hot flashes. Additional analyses presented demonstrated that Pristiq reduced the number of nighttime awakenings and mood disturbances in postmenopausal women with hot flashes and night sweats and did not have a negative effect on sexual function.

The data were presented at the 55th Annual Meeting of the American College of Obstetricians and Gynecologists (ACOG) in San Diego. Pristiq is currently under review by the U.S. Food and Drug Administration (FDA) and could be the first non-hormonal treatment for menopausal hot flashes and night sweats.

"Millions of women experience hot flashes and night sweats during menopause, but there are currently no effective non-hormonal treatment options approved by the FDA," says Joseph Camardo, M.D., Senior Vice President, Global Medical Affairs, Wyeth Pharmaceuticals. "The data indicate Pristiq has the potential to expand the range of effective treatment options by providing a non-hormonal choice for menopausal women with moderate-to-severe vasomotor symptoms."

Evaluation of Safety and Efficacy

Three studies presented examine the efficacy of Pristiq at various doses while also evaluating its safety and tolerability profile. The most common side effect in all three studies was nausea, which was generally mild to moderate, was dose-dependent, and resolved quickly, on average within three days.

Efficacy and Safety of Desvenlafaxine Succinate for Treatment of Menopausal Vasomotor Symptoms

This one-year, multicenter, randomized, double-blind, placebo-controlled trial evaluated the safety and efficacy of Pristiq at multiple doses. The study included 689 postmenopausal women with 50 or more moderate-to-severe hot flashes per week. Primary endpoints were assessed at weeks four and 12 and included the daily number and severity of hot flashes and night sweats.

Results from this study showed a reduction in the number and severity of hot flashes and night sweats at weeks four and 12 for several of the doses investigated. There was a rapid onset of action - within one week of starting therapy.

Efficacy of Desvenlafaxine Succinate in the Treatment of Menopausal Vasomotor Symptoms

This six month multicenter, randomized, double-blind, placebo-controlled trial evaluated the efficacy and safety of Pristiq. The study included 541 postmenopausal women with 50 or more moderate-to-severe hot flashes per week. Primary endpoints were assessed at weeks four and 12, and included the daily number and severity of hot flashes and night sweats.

Pristiq demonstrated significant improvements compared with placebo for all primary endpoints. A statistically significant reduction in the number of hot flashes (60 to 66 percent) was maintained throughout the 26-week study period.

A Placebo-Controlled Trial of Desvenlafaxine Succinate and Tibolone for Menopausal Vasomotor Symptoms

This 12-week, multicenter, randomized, double-blind, placebo- and active-controlled trial evaluated the safety and efficacy of Pristiq. The study included 451 postmenopausal women with 50 or more moderate-to-severe hot flashes per week, in multiple countries outside of the United States.

Results showed that at weeks four and 12, all groups experienced a decrease in the number and severity of hot flashes from baseline. There was no statistically significant difference between Pristiq and placebo; whereas, the difference between active comparator and placebo was significant.

Additional Analyses

Additional analyses of key secondary endpoints from these three studies were also presented.

Effects of Desvenlafaxine on Sleep and Mood in Menopausal Women: A Pooled Analysis

This pooled analysis of two studies (Efficacy and Safety of Desvenlafaxine Succinate for Treatment of Menopausal Vasomotor Symptoms and Efficacy of Desvenlafaxine Succinate in the Treatment of Menopausal Vasomotor Symptoms) showed that Pristiq reduced the number of nighttime awakenings, increased the number of average minutes slept, and improved the quality of sleep score, compared with placebo. In addition, at the doses studied, Pristiq showed greater improvements from baseline in the Profile of Mood States (POMS) total mood score compared with placebo, with significant improvements in four out of six domains.

Sexual Function in Women Treated with Desvenlafaxine Succinate for Menopausal Vasomotor Symptoms

This secondary analysis of the 52-week trial (Efficacy and Safety of Desvenlafaxine Succinate for Treatment of Menopausal Vasomotor Symptoms) previously described showed that at week 12, women taking Pristiq did not experience a significant decrease in sexual function. This was measured by the Sex Effects Scale (Sex FX), a questionnaire developed to evaluate states and changes in sexual function in subjects taking antidepressant medications. Overall, there was a low incidence of sexual adverse events, and there was no statistical difference between Pristiq and placebo.

About Pristiq

Pristiq is a serotonin-norepinephrine reuptake inhibitor (SNRI) being studied by Wyeth as a potential treatment for multiple indications, including moderate-to-severe menopausal hot flashes and night sweats. Pristiq is believed to work by affecting the balance of serotonin and norepinephrine. These chemicals, known as neurotransmitters, are thought to play an important role in the brain to regulate body temperature and, during menopause may become imbalanced leading to hot flashes and night sweats.

Wyeth filed a New Drug Application June 23, 2006, with the FDA for Pristiq for the treatment of moderate-to-severe vasomotor symptoms associated with menopause. If approved, Wyeth anticipates that Pristiq will be the first and only non-hormonal medication indicated for the treatment of moderate-to-severe vasomotor symptoms associated with menopause in the United States. Based on review of publicly disclosed studies, Pristiq is the first non-hormonal therapy to be studied in long-term (six and 12 months), placebo-controlled trials. Pristiq is also under review for the treatment of major depressive disorder, and Wyeth received an approvable letter from the FDA on January 23, 2007, for this indication.

About Wyeth Pharmaceuticals

Wyeth Pharmaceuticals, a division of Wyeth, has leading products in the areas of women's health care, infectious disease, gastrointestinal health, central nervous system, inflammation, transplantation, hemophilia, oncology, vaccines and nutritional products.

Wyeth is one of the world's largest research-driven pharmaceutical and health care products companies. It is a leader in the discovery, development, manufacturing and marketing of pharmaceuticals, vaccines, biotechnology products and non-prescription medicines that improve the quality of life for people worldwide. The Company's major divisions include Wyeth Pharmaceuticals, Wyeth Consumer Healthcare and Fort Dodge Animal Health.

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