Wyeth Pharmaceuticals, a division of Wyeth, presented the first phase 3 fracture data for bazedoxifene, a selective estrogen receptor modulator, at the American Society for Bone and Mineral Research Annual Meeting.
In a three-year study, data showed that bazedoxifene 20 mg and 40 mg significantly reduced the relative risk of new vertebral fractures by 42 per cent and 37 per cent, respectively, compared with placebo. A post-hoc subgroup analysis of women at higher fracture risk showed that bazedoxifene 20 mg significantly reduced the incidence of non-vertebral fracture by 52 per cent relative to placebo.
With regard to the safety and tolerability observed in this clinical trial, a non-statistically significant increase in the incidence of venous thromboembolic events was observed in all active treatment groups compared with the placebo group. No safety concerns related to the reproductive systems, including breast, were observed in the bazedoxifene treatment groups.
Wyeth received an approvable letter relating to its pending new drug application for bazedoxifene for the prevention of postmenopausal osteoporosis from the US Food and Drug Administration (FDA) on April 23, 2007. In July 2007, Wyeth submitted a separate new drug application to the FDA for bazedoxifene for the treatment of postmenopausal osteoporosis. The efficacy data for bazedoxifene presented at the meeting represents only a portion of the totality of safety and efficacy data that the Company has submitted to FDA.
In the oral presentation, "Efficacy of Bazedoxifene in Reducing New Vertebral Fracture Risk in Postmenopausal Women with Osteoporosis: Results from a Three-Year, Randomized, Placebo- and Active-Controlled Clinical Trial," which enrolled 7,492 postmenopausal women between the ages of 55 and 85 with moderate to severe osteoporosis, bazedoxifene showed significant risk reduction, compared with placebo, for new vertebral fractures. Specifically, the three-year incidences of new vertebral fracture were 2.3 per cent, 2.5 per cent, 2.3 per cent and 4.1 per cent in the bazedoxifene 20 mg, bazedoxifene 40 mg, raloxifene 60 mg and placebo groups, respectively.
In addition, a subgroup analysis of 1,782 women at higher risk for fracture showed that bazedoxifene significantly reduced the incidence of non-vertebral fracture. In particular, the non-vertebral fracture incidence was 3.0 percent, 3.8 per cent, 5.9 per cent and 6.3 per cent in bazedoxifene 20 mg, bazedoxifene 40 mg, raloxifene 60 mg and placebo groups, respectively, with a risk reduction of 46 per cent, compared with placebo, when both bazedoxifene doses were combined.
According to the National Osteoporosis Foundation, the number of women of menopausal age who have osteoporosis or are at risk for developing the disease will increase from almost 30 million in 2002 to nearly 41 million by 2020. Osteoporosis causes approximately 1.5 million fractures each year in the United States alone, and the risk of fracture significantly increases in women usually after age 50. Non-vertebral fractures are more common than vertebral fractures and account for an estimated 300,000 hip and 250,000 wrist fractures, in addition to an estimated 250,000 fractures at other non-vertebral sites such as the clavicle, humerus, pelvis and leg.