Objective: To evaluate the efficacy and safety of desvenlafaxine (administered as desvenlafaxine succinate) vs. tibolone and placebo for menopausal vasomotor symptoms and the incidence of uterine bleeding.
Methods: This 12-week, double-blind, randomized, controlled trial was conducted at 35 sites in Europe, two sites in South Africa, and one site in Mexico. Postmenopausal women with ≥50 moderate or severe hot flushes per week (n = 485) were randomized to desvenlafaxine 100 mg/day, tibolone 2.5 mg/day, or placebo. Reduction in the average daily number of moderate and severe hot flushes at weeks 4 and 12 (primary endpoint) was evaluated using analysis of covariance. Safety assessments included incidence of uterine bleeding, adverse events, laboratory values, and vital signs.
Results: At week 12, no statistically significant difference was observed in reduction of the average daily number of moderate and severe hot flushes for desvenlafaxine (-5.78) vs. placebo (-5.82; p = 0.921), although time to 50% reduction was significantly less than placebo (13 vs. 26 days, p = 0.006). Hot flush reduction with tibolone (-8.21) was significantly greater than placebo (p < 0.001). Nausea was the most common adverse event with desvenlafaxine, was generally mild to moderate, and resolved within the first 2 weeks. Significantly more subjects experienced bleeding with tibolone (23%) vs. desvenlafaxine (12%; p < 0.024) or placebo (9%; p < 0.001).
Conclusions: Desvenlafaxine did not separate from placebo in reducing the number of moderate to severe hot flushes at week 12, although it did allow women to achieve 50% reduction sooner than placebo. Tibolone did separate from placebo, but with smaller than expected effect. The placebo effect was high (57%). Adverse drug reactions were consistent with the known safety profile of desvenlafaxine, and significantly more women who received tibolone experienced episodes of bleeding compared with women who received desvenlafaxine or placebo.