Bazedoxifene/conjugated Estrogens (BZA/CE): Incidence of Uterine Bleeding in Postmenopausal Women

Objective: To evaluate the effect of bazedoxifene/conjugated estrogens (BZA/CE), a tissue selective estrogen complex, on uterine bleeding in postmenopausal women.

Design: International, multicenter, randomized, double-blind, placebo- and active-controlled, phase III study (Selective estrogen Menopause And Response to Therapy [SMART]-1).

Setting: Outpatient clinical.

Patient(s): Healthy, postmenopausal women (N = 3,397) aged 40 to 75 years with an intact uterus.

Intervention(s): Daily oral therapy with BZA 10, 20, or 40 mg, each with CE 0.625 or 0.45 mg, raloxifene 60 mg, or placebo.

Main Outcome Measure(s): Cumulative amenorrhea profiles and the incidence of bleeding or spotting over 2 years.

Result(s): Treatment with BZA 20 or 40 mg with CE 0.625 or 0.45 mg was associated with rates of cumulative amenorrhea (>83% during cycles 1-13 and >93% during cycles 10-13) and bleeding or spotting that were comparable to those with placebo. Subjects who received BZA 10 mg/CE 0.625 mg experienced slightly lower cumulative amenorrhea rates throughout the study compared with placebo-treated subjects.

Conclusion(s): Postmenopausal women treated with BZA 20 or 40 mg with CE 0.625 or 0.45 mg had high rates of cumulative amenorrhea that were similar to those reported with placebo. This new menopausal therapy may offer a favorable bleeding and tolerability profile.