The first member of a new class of osteoporosis drugs reduced spinal fractures by about two-thirds in post-menopausal women and in men undergoing hormone-deprivation therapy for prostate cancer, according to two studies released online Tuesday by the .
The drug, called denosumab, blocks production of cells called osteoclasts that break down bones, and physicians have high hopes for it because of its efficacy, ease of administration and apparent lack of severe side effects. But it's a biological agent rather than a chemical, meaning it's difficult to produce, and it is likely to be the highest-priced osteoporosis drug in an already-crowded marketplace.
The most well-known osteoporosis drug, Fosamax, is in a class known as bisphosphonates. Those drugs actually kill osteoclasts but carry the risk of stomach and esophageal irritation and have been linked to some cases of jaw necrosis.
Amgen, the manufacturer of denosumab, has not said how much the drug will cost, but analysts expect it to be at least $2,000 a year -- and potentially much higher -- and predict yearly sales of $2 billion to $3 billion.
Already, many insurance companies are pushing physicians to the generic version of Fosamax, alendronate, which costs about $100 a year.
Some medical experts think a high price would discourage the use of denosumab.
"If it is going to be quite a bit higher than the next-most-expensive drug, I don't see that it is going to be used so widely," said Dr. Frederick R. Singer, director of the endocrine/bone disease program at John Wayne Cancer Institute in Santa Monica, who was not involved in the research.
An advisory committee of the Food and Drug Administration will meet Thursday to consider Amgen's application for approval of the drug, to be called Prolia, for treating osteoporosis in women and in men being treated for prostate cancer. If approved, it would be the first drug specifically approved for treating such men.
As many as half of women and 30% of men will suffer an osteoporosis-related fracture during their lifetime, according to the International Osteoporosis Foundation. About a third of the 2 million American men with prostate cancer undergo hormone-deprivation therapy to prevent release of the hormones that fuel the tumors, which sharply increases their risk of osteoporosis.
The two new trials were designed and funded by Amgen, and most of the researchers were Amgen employees or recipients of funds from the company. Nonetheless, osteoporosis experts were impressed.
