An advisory committee for U.S. Food and Drug Administration meets Friday to review the safety of a popular class of osteoporosis drugs called bisphosphonates amid worry that their long-term use could cause rare fractures of the thighbones and affect the jawbone. The committee will evaluate whether women should temporarily stop using the drugs or use them for only a few years.
In September, a report by the American Society of Bone and Mineral Research linked bisphosphonates, which include the drugs Fosamax and its generic, Boniva and Actonel, to rare femur fractures among patients with osteoporosis. Of 310 cases, 94 percent of the patients were taking bisphosphonates. While the report's authors did not say that the osteoporosis medications caused the fractures, they recommended that the FDA change the drugs' labeling to warn patients about the possible risks.
Dr. Elizabeth Shane, a co-author and professor of medicine at Columbia University College of Physicians and Surgeons said, “Based on the report, we now feel that there is a definitive relationship between these class of drugs and these fractures, and it's even stronger in those taking those drugs for a long time.” But she also said bisphosphonates could help prevent other types of fractures and patients should still take them. She continues to prescribe bisphosphonates and evaluates each patient individually. Patients who take them, however, should be aware of warning signs, such as a hip, thigh or groin pain. “I think we have to be responsible in acknowledging the pain and suffering people went through who have the rare fractures,” she said, “but there's also pain in the more common fractures that these drugs help.” Many doctors are changing the way they prescribe bisphosphonates, taking patients off the drugs after two or three years. Others recommend a five-year limit.
Fosamax, a blockbuster drug that has earned billions for Merck and Co., has also been linked to severe muscle pain and osteonecrosis of the jaw, also known as jawbone death. Merck responded to the initial reports of jawbone death by saying the clinical information was inconclusive.
“In worldwide post-marketing experience with Fosamax, Fosamax Plus D, rare reports consistent with osteonecrosis of the jaw have been received. Many of these reports lack sufficient clinical details to make definitive assessments or are confounded, particularly since a generally accepted definition of ONJ in the general population is unknown,” Merck wrote in a statement.
Fosamax was first approved in 1995 to treat postmenopausal osteoporosis and Paget’s disease of the bone, conditions that weaken bones. It has also been marketed, controversially, for a pre-osteoporosis condition called osteopenia. The Fosamax patent expired in 2008 and generics have flooded the market.
Dr. Susan M. Ott, an associate medical professor and bone specialist at the University of Washington, who takes no research funds from industry, summarized the current science in a 12-page review article published by the Cleveland Clinic Journal of Medicine on Thursday.
“In my opinion, after five years in most cases it ought to be stopped,” Dr. Ott said. She prescribes the drugs for shorter periods, but said evidence shows growing risks and no proven benefits after five years. “The longest anybody could have taken this drug is 15 years now,” Dr. Ott said. “It’s an ongoing experiment, and there are a few million women in the country who are participating in it. I keep wanting to say, You’re all guinea pigs after five years because that’s when the studies stopped.”