The phase 2 data demonstrating twice-yearly injections Amgen's denosumab (previously referred to as AMG 162), a RANK Ligand inhibitor, significantly increased bone mineral density (BMD) in the spine.

The 412 volunteers, who were all women with low bone density, were given the drug at one of seven doses or either a placebo or the Merck & Co. drug Fosamax, also known as alendronate.

Researchers reported that subcutaneous injections of denosumab significantly increased BMD at the total hip from 1.9 to 3.6 per cent in women who were administered the therapy twice yearly as compared with a decrease of 0.6 per cent in the placebo group at one year. Results also indicated that denosumab had a rapid onset of action. A significant decrease in serum levels of C-telopeptide, a biomarker of bone resorption, was achieved within 72 hours after dosing.

"These exciting data suggest that denosumab, when administered in twice-yearly injections, may show promise in the treatment of osteoporosis. Continued research will further our understanding of the potential of denosumab in bone loss management," said Michael McClung, principal investigator of the denosumab study, Providence Portland Medical Centre, and director of the Oregon Osteoporosis Centre, Portland.

Data recently presented at the American College of Rheumatology 2005 Annual Scientific Meeting show further increase in bone mineral density in postmenopausal women with osteoporosis after two years of treatment.

The results were comparable to those seen for Fosamax, which produced a 4.6 per cent increase at the one-year point. Volunteers who received a placebo lost bone in the spine.

In the US today, 10 million individuals are estimated to already have the disease and almost 34 million more are estimated to have low bone mass, placing them at increased risk for osteoporosis. Of the 10 million Americans estimated to have osteoporosis, eight million are women and two million are men.