Denosumab reduces fractures in postmenopausal women with osteoporosis

Fractures are a major cause of disability and health care costs among postmenopausal women. Now a study in the New England Journal of Medicine highlights an alternative therapy that prevents fractures in postmenopausal women with osteoporosis.

The study found that denosumab, a human monoclonal antibody, reduced the risk of new vertebral fractures by 68 percent, compared to a placebo, in postmenopausal women with osteoporosis. It also found that denosumab reduced the risk of new hip fractures by 40 percent, and nonvertebral fractures by 20 percent.

"Denosumab works in a new way to prevent bone loss" says Steven Cummings, M.D., of the San Francisco Coordinating Center at the California Pacific Medical Center Research Institute, and the lead author of the study. "This trial shows that it reduces the risk of all major types of fractures in women who have osteoporosis."

The researchers followed 7,868 women between the ages of 60 and 90 who had a previous diagnosis of osteoporosis. They were randomly assigned to get either a 60 mg injection of denosumab or a placebo every six months over three years. The women were given a spine radiograph every year to see if they had suffered any vertebral fractures. In addition the researchers measured the women's bone mineral density every year at the hip, and after 36 months at the lumbar spine.

At the end of the 36 months, 2.3 percent of the denosumab group had vertebral fractures, compared to 7.2 percent in the placebo group. Denosumab was also associated with an increase in bone mineral density of 8.8 percent at the lumbar spine and 6.4 percent at the hip, compared to the placebo group.

There were no any significant differences between the 2 groups in the overall rates of cancer, infections, or heart disease.

"Most patients who start taking pills to prevent fractures stop taking them within one year," says Dr. Cummings. "Denosumab is given twice a year as a simple injection in the doctor's office. Some patients may prefer this type of treatment and it has the potential to improve compliance with treatment"

Denosumab is manufactured by Amgen which helped fund the FREEDOM (Fracture Reduction Evaluation of Denosumab in Osteoporosis every 6 Months) study.

Dr. Cummings received both consulting fees and grant support from Amgen for his work.