Osteoporosis Patients may Benefit From New Drug - Two Injections of Denosumab per Year will Increase Bone Mass in Postmenopausal Women

February 22nd 2006

Osteoclasts

New research has found that an investigational therapy for bone loss, denosumab, demonstrated significant increases in bone mineral density (BMD) in postmenopausal women with osteoporosis. A person’s BMD can be an indicator for fracture risk, according to a study published in the Feb. 23, 2006 issue of The New England Journal of Medicine.

Denosumab is a RANK Ligand inhibitor under development by Amgen. Ligand is a protein that is the primary “mediator” of osteoclast formation, function and survival. These osteoclasts are responsible for bone removal.

This study is in the second stage and the researchers were able to demonstrate that “denosumab provides rapid and sustained responses of bone metabolism in patients with low BMD.” Denosumad can be administered twice yearly and will increase total hip, spine, distal 1/3 radius and total body BMD similar to current therapy.

The subcutaneous injections of denosumab increased BMD at the lumbar spine from 3.0 to 6.7 percent after 12 months as compared with a decrease of 0.8 percent with placebo. The researchers also saw an improvement in hip BMD from 1.9 to 3.6 percent in women who received denosumab compared with a decrease of 0.6 percent in the placebo group.

The drug also acted quickly. According to the study “denosumab had a rapid onset of action, inhibiting the action of osteoclasts within 72 hours”. Dr. Michael McClung, MD said “The ability to control bone metabolism and increase BMD so effectively with such a convenient dosing regimen shows a potential advantage of this therapeutic strategy over current therapies." Dr. McClung is the principal investigator of the denosumab study and director of Oregon Osteoporosis Center at Providence Portland Medical Center in Portland, Oregon.

The adverse side effects were similar to those of the placebo and Fosamax. Because the drug is injected under the skin, the patients would avoid the gastrointestinal upset which is a side effect of the currently prescribed osteoporosis medications known as bisphosphonates.