Bisphosphonates (e.g. Fosamax, Boniva, and the like) are drugs prescribed for treatment and prevention of osteoporosis in postmenopausal women, but concerns have been raised about possible adverse effects of using the drugs for long periods of time, such as “atypical” femur (thigh) fractures, osteonecrosis (death of the jaw bone), and esophageal cancer.
Last fall, the FDA requested changes to bisphosphonate labels to warn of the fracture risk, explain that the optimal amount of time to take the drug is not known, and recommend that patients and their doctors periodically reevaluate whether the drug should be continued.
Recently, FDA committees on reproductive health drugs and drug safety/risk management met to discuss long-term (>3-5 years) use of bisphosphonates and these potential complications.
In a briefing document prepared for the meeting, the FDA reviewed evidence on these relatively rare but concerning effects, and concluded, “The safety of long-term bisphosphonate therapy continues to be unclear as study results are conflicting as to whether or not ONJ [jaw osteonecrosis], atypical femoral fractures or esophageal cancer are associated with use of bisphosphonates for the prevention and treatment of osteoporosis.”
The agency further concluded that the evidence suggests an increased prevalence of jaw osteonecrosis with longer use, especially of 4 or more years, but that larger studies are needed. It also writes that “Atypical fractures…appear to have a strong association with bisphosphonates but there is no current consensus on the extent to which cumulative use of bisphosphonates increases the risk of this rare type of fracture. Finally, no definitive evidence is available to support an association between esophageal cancer and long-term use of bisphosphonates.”
In discussing whether long-term use of bisphosphonates would have a benefit of reducing osteoporosis-related fractures, the agency found no clear benefit of continuing, stating, “These results suggest no significant advantage of continuing drug therapy beyond 5 years.”
The New York Times also has coverage of the recent FDA meeting, and notes: “The committee also called for more study of the overall effectiveness of the drugs in their desired goal of preventing fractures. And the advisers recommended that the F.D.A. take a close look at why the drugs are prescribed as preventive medicine for women who do not even have osteoporosis.”
For more on this topic, see our previous posts, and the National Women’s Health Network, which also raises the issue of whether these drugs should be marketed and prescribed for prevention to healthy women.