Two experimental osteoporosis drugs showed promise in clinical trials and increased bone mineral density in postmenopausal women with osteoporosis, according to researchers.
Denosumab made by Amgen and odanacatib made by Merck & Co., are a new class of a drug that may become the first biologic drugs to treat osteoporosis.
Both of these drugs are a very new way of tackling treatment of osteoporosis, says Susan Bukata, MD, an orthopedic surgeon and associate professor at The URMC Center for Bone Health.
“This is the new frontier into osteoporosis and the first step in biologics for osteoporosis treatment,” Bukata tells WebMD.
How the Drugs Work
Bones are a dynamic tissue that never rest, they are constantly being reshaped. Both drugs – odanacatib and denosumab - target osteoclasts.
Osteoclasts are a type of bone cell that removes bone tissue. Osteoblasts, another type of cell are responsible for new bone formation.
Typically, around the age of 30, most people reach maximum bone mass and the stability between bone breakdown and bone buildup begins shifting in the favor of bone loss. In the case osteoporosis, the bones become dangerously brittle and weak.
The basic concept of new treatment with these drugs is to rebalance bone building and bone loss to give the osteoblasts a chance to create new bone.
Denosumab’s Clinical Trial
Denosumab has completed phase III trials, the last of which are required by the FDA before the drug can be submitted for approval.
For the trial – which included postmenopausal women with low bone mineral density (BMD) – were split into two groups. One group was given an injection of denosumab twice a year. And the other group was given a weekly dose of alendronate (the active ingredient found in Fosamax, made by Merck & Co.).
After a year, the patient group taking denosumab experienced greater improvements in BMD in the hips and lumbar spine, than in the group that was given aldenronate.
Odanactib takes on a different role than that of denosumab. This drug focuses on an enzyme called cathespin K, which reduces osteoclast activity.
Phase III of odanactib’s trial is just underway and Merck is currently enrolling particpants. But the results from its phase 2b clinical trial have been promising.
For the trial, postmenopausal women with osteoporosis were given a weekly dose of odanacatib or a placebo. After two years, the women who took a 50 mg dose of odanactib weekly showed significant improvement in bone mineral density in their hips and lumbar spine.
Phase III trials will determine the odanactib’s ability for fracture prevention in postmenopausal women with osteoporosis. The results of the trial may take up to four years.
The future of odanactib and denosumab for osteoporosis treatment, if approved by the FDA, will depend largely on how well they stack up against currently approved drugs for osteoporosis treatment. They have to be as good as current drugs, if not better.
Results from the trials were recently presented this week in Montreal at the annual meeting of the American Society for Bone and Mineral Research show.
In another recent story, IB reported an expert panel looking at Pfizer’s controversial osteoporosis drug Fablyn (lasofoxifene), resulted in nine panel members concluding the benefits outweigh the risk and three saying it did not. One member abstained. The FDA rejected the drug three years ago. #