Trial finds that osteoporosis drug increases bone turnover but does not lower fracture risk

A study conducted by a group of Japanese bone researchers has found that the osteoporosis drug bazedoxifene, which is still in development, stimulates bone turnover but does not decrease fracture risk in postmenopausal women.

The report, which appears in the Journal of Bone and Mineral Research (JBMR), found that daily doses of the medication increased participants' lumbar bone mineral density (BMD) by up to 2.74 percent over a two-year period.

By contrast, women who received a placebo lost 0.65 percent of their total lumbar BMD in the same interval.

Among the more than 400 postmenopausal women who took part in the study, those who received bazedoxifene also experienced small improvements in hip and femur BMDs. Again, those who received a placebo saw decreases in their pelvic and femoral BMDs.

The study itself was funded by Pfizer, which is currently seeking approval of the drug from the U.S. Food and Drug Administration (FDA). So far, the medication has been approved by the European Medicines Agency but not by the FDA.

Bazedoxifene is a selective estrogen receptor modulator (SERM), which is a type of pharmacological treatment designed to stimulate estrogenic activity in specific tissues. The study noted that this new medication is similar to raloxifene, another osteoporosis-fighting SERM that has been approved by the FDA for use among postmenopausal women.

However, while a 2006 article in the New England Journal of Medicine determined that raloxifene reduces the risk of postmenopausal vertebral pressure fractures "without a shadow of a doubt," no such confirmation yet exists for bazedoxifene.

In fact, in the JBMR report, researchers found that bazedoxifene did not significantly prevent broken bones of any kind, compared to a placebo.

Fractures are one of the most common causes of disability among aging Americans. The National Osteoporosis Foundation (NOF) estimates that in the U.S., osteoporosis contributes to more than 2 million fractures each year, a figure that will likely rise to 3 million by 2025.