New Osteoporosis Drug Coming?
2 Positive Studies Published on Experimental Drug Denosumab; FDA Panel Review This Week
Aug. 11, 2009 -- The experimental drug denosumab may be on its way to becoming the newest way to treat osteoporosis.
Denosumab, a biological drug given by injection every six months, looks safe and effective, researchers report in today's advance online edition of the New England Journal of Medicine.
An FDA advisory panel will meet Aug. 13 to decide whether to recommend denosumab for FDA approval. The FDA often follows the advice of its advisory committees, but it doesn't have to.
Denosumab works differently than other osteoporosis drugs. It binds to a protein called RANKL, which cells called osteoclasts need to break down bone as part of the bone remodeling process.
The idea behind denosumab is to slow the bone-breakdown process in people whose bones are already dangerously thin.
WebMD first reported on denosumab in September 2008, when news about the drug's potential to treat osteoporosis in postmenopausal women was presented at the annual meeting of the American Society for Bone and Mineral Research in Montreal.
Now, that trial's results have been published, along with a separate study in men with prostate cancer taking bone-weakening hormone therapy to treat their cancer.
In both studies, patients got a shot of either denosumab or a placebo every six months for three years. And in both studies, fractures were rarer in patients taking denosumab.
In the postmenopausal osteoporosis study, which included 7,800 women 60-90 years old with osteoporosis, new vertebral fractures occurred in 2.3% of patients taking denosumab, compared with 7.2% of patients taking the placebo.
That's a difference of 68%, notes researcher Steven Cummings, MD, director of the San Francisco Coordinating Center at the California Pacific Medical Center and a professor of medicine and epidemiology at the University of California at San Francisco.
"It's more effective for reducing vertebral fractures than I expected ... 68% is a very powerful reduction," Cummings tells WebMD.
In the prostate cancer study, which included more than 1,400 men with prostate cancer on bone-weakening hormone therapy, new vertebral fractures occurred in 1.5% of patients taking denosumab, compared with 3.9% of patients who got the placebo.
"To see this very dramatic 62% decrease in vertebral fractures in three years in this relatively high-risk population of men is very impressive," researcher Matthew Smith, MD, PhD, tells WebMD. Smith is the director of genitourinary medical oncology at Massachusetts General Hospital Cancer Center.