Bazedoxifene: a novel selective estrogen receptor modulator for postmenopausal osteoporosis

Abstract

Several new selective estrogen receptor modulators (SERMs) are currently under clinical development for the prevention and/or treatment of postmenopausal osteoporosis, with the goal of optimizing the estrogen receptor agonist/antagonist activity in target tissues. Bazedoxifene is a novel SERM under clinical investigation for the prevention and treatment of postmenopausal osteoporosis. Emerging clinical data have shown that bazedoxifene is effective in preventing bone loss and osteoporotic fractures in postmenopausal women, with no evidence of breast or endometrial stimulation.

 Two large, prospective, international phase 3 studies have been completed. In postmenopausal women at risk for osteoporosis, bazedoxifene has been shown to preserve bone mineral density and to reduce bone turnover. In postmenopausal women with osteoporosis, bazedoxifene has demonstrated significant protection against new vertebral fractures and against non-vertebral fractures in women at higher fracture risk. The treatment effects of bazedoxifene were supported by findings from independent re-analyses using the Fracture Risk Assessment Tool (FRAX®), which showed that bazedoxifene significantly reduced the risk of all clinical and morphometric vertebral fracture and of non-vertebral fracture in women at or above a FRAX-based threshold. Bazedoxifene was generally safe and well tolerated in the phase 3 studies and showed neutral effects on the breast and an excellent endometrial safety profile; such attributes allow for the partnering of bazedoxifene with conjugated estrogens for menopausal symptom relief. Collectively, these results suggest that bazedoxifene may be a promising new therapy for the prevention and treatment of postmenopausal osteoporosis as a monotherapy or in combination with conjugated estrogens in menopausal hormone therapy.

Key words:

• BAZEDOXIFENE
• OSTEOPOROSIS
• SELECTIVE ESTROGEN RECEPTOR MODULATOR
• POSTMENOPAUSAL
• OSTEOPOROTIC FRACTURE
• BONE MINERAL DENSITY

Conflict of interest  Dr de Villiers has acted as a consultant and/or investigator for Servier, Novo Nordisk, Wyeth Ayerst, Pfizer, Bayer Schering, Aventis, and Novartis.

Source of funding  Editorial support for the writing of this manuscript was provided by Bo Choi, PhD, of MedErgy, and was funded by Wyeth Pharmaceuticals, Collegeville, PA, which was acquired by Pfizer Inc in October 2009. The author was not compensated and retained full editorial control over the content of the manuscript.