Yesterday, Wyeth Pharmaceuticals, a division of Wyeth (WYE), announced data from a placebo-controlled late-stage study of its drug candidate bazedoxifene 20 mg in postmenopausal women with osteoporosis. The results indicated that women who took bazedoxifene had a lower risk of new fractures to their vertebrae.
As a reminder, 20 mg and 40 mg doses of the drug were initially tested, along with raloxifene 60 mg and a placebo, over a three-year period in 7,492 postmenopausal women aged between 55 and 85 and with moderate to severe osteoporosis. The results were disclosed in 2007. They revealed that the three-year incidences of new vertebral fracture were 2.3%, 2.5%, 2.3% and 4.1% in the bazedoxifene 20 mg, bazedoxifene 40 mg, raloxifene 60 mg and placebo groups, respectively. On conclusion of the three-year study, a total of 4,216 subjects were enrolled in the extension to five years.
The raloxifene 60 mg arm was discontinued in the extended version of the trial. Some of the subjects took 20 mg of bazedoxifene per day during the entire trial period. Others took 40 mg per day for four years and were switched to the 20 mg group in the last year of the study. Both groups had fewer new vertebral fractures than patients who only took a placebo.
About 4.5% of women who took 20 mg of the drug exclusively had new fractures, compared with 3.9% who started off on the larger dose, and 6.8% of placebo patients.
Bazedoxifene was approved for sale in the European Union under the name Conbriza in April 2009. However, it is still under review by the U.S. Food and Drug Administration.
The osteoporosis market represents a huge commercial potential with global sales of osteoporosis medications coming in at about $8.4 billion in 2008. The indication, which results in bone fragility coupled with an increased risk of fractures, affects approximately 75 million people in the United States, Europe and Japan. It is estimated that a significant amount of a woman’s expected bone loss occurs in the postmenopausal years. Consequently, the effective treatment of postmenopausal osteoporosis could lead to significant improvement in the overall health.
We note that Amgen (AMGN) is currently seeking approval for denosumab for the treatment and prevention of postmenopausal osteoporosis and bone loss in patients undergoing hormone ablation for either prostate or breast cancer. We believe the candidate has the potential to capture a major share of the osteoporosis market once launched.
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