WASHINGTONA panel of health experts who advise the Food and Drug Administration says a long-established bone strengthening inhalable drug calcitonin salmon should no longer be taken by women.
The panel voted 12-9 to recommend against the inhalable osteoporosis drug because there is little evidence it helps brittle bones and it may actually increase the risk of cancer.
Currently, Novartis and Upsher-Smith market calcitonin salmon in nasal spray form as Miacalcin and Fortical, respectively.
The drug has been prescribed for osteoporosis in postmenopausal women since the 1980s.
But health authorities around the world have been reviewing the drug's safety after two recent studies showed a slightly higher rate of cancer among patients taking calcitonin pills. The drug is also available as an injection to treat other conditions, including excess calcium in the blood.
The European Medicines Agency concluded last July that calcitonin should no longer be used to treat osteoporosis, due to the drug's cancer risk.
An internal FDA memo released ahead of Tuesday's meeting said it's difficult to draw a direct link between the drug and cancer. However, "the potential for a cancer risk with calcitonin salmon therapy cannot be ignored. The majority of all calcitonin salmon trials showed an increased risk estimate."
A narrow majority of panelists voted against continued use of the drug, pointing out that the drug has not been shown very effective at preventing bone fractures.
"I think the cancer risk seems to be low, but it tips the balance for this drug, which has very little evidence of efficacy," said Dr. Amy Whitaker, a professor of obstetrics and gynecology at the University of Chicago.
But other panelists said the drugs are an important option for patients who have bad reactions to newer drugs, including bisphosphonate drugs like Fosamax.
"We have a whole lot of patients who can't take the other drugs, and I think our patients would be in worse shape without this," said Dr. Bart Clarke, professor of endocrinology at the Mayo Clinic College of Medicine in Rochester, Minn.
Calcitonin salmon is a manmade version of a hormone found in the salmon fish that prevents bone breakdown and increases bone density. The drug is used to treat osteoporosis in women who are at least 5 years past menopause or cannot or do not want to take estrogen products, according to the National Institutes of Health.
It is usually used as a once a day spray in alternating nostrils.
Calcitonin prescriptions have plummeted in recent years amid safety concerns about the drugs. Between 2006 and 2011 the number of U.S. patients receiving the drug fell 51 percent to 205,000.
The FDA approved the drugs from Novartis and Upsher-Smith based on studies showing that they increased bone mineral density. However, no studies have definitely shown that higher density actually reduces bone fractures. The largest study of calcitonin, which followed 1,200 women for about five years, was plagued by logistical problems, including a high level of patients who dropped out.
The FDA often approves drugs based on so-called surrogate endpoints, or initial measures that suggest the drug will make real improvements in patient health. In cancer drugs, for example, tumor shrinkage is considered a predictor of longer survival.
Drugmakers favor the approach because it helps them get products to market sooner. But it has proven problematic for the FDA when drugs don't live up to their initial promise.
The FDA panel was nearly unanimous that any future calcitonin drugs should be required to show real effectiveness in preventing bone fractures. The group voted 20-1 in favor of such a requirement.
The FDA does not have to follow the advice of its panels, though it often does.