A clinical trial of Amgen’s experimental bone drug on 7,800 postmenopausal women with osteoporosis showed a 68% reduction in the risk of spinal fractures in women with osteoporosis. Denosumab has been found to also reduce the risk of hip fractures by 40% and the risk of all non-spinal fractures by 20%. 

However, Reclast from Novartis achieved a 70% reduction in spinal fractures. The hip fracture risk reduction of 40% achieved by Amgen’s Denosumab is in line or better than that achieved by some other drugs. Scientists caution that the only way to truly compare drugs is head-to-head in a clinical trial. Amgen, expected to apply for federal approval early 2009, could see Denosumab reaching the market late 2009 or early 2010. 

The main osteoporosis drugs in the form of pills include Fosamax from Merck and its generic equivalents; Boniva from Roche and GlaxoSmithKline; Actonel from Procter & Gamble and Sanofi-Aventis and Reclast from Novartis. 

Denosumab, by contrast is an injection, given once every six months, the preferred choice of patients preferring a 6-monthly Denosumab injection to weekly bisphosphonate pills. Those opting to discontinue pills will see Denosumab competing directly with Novartis’s Reclast. 

With near identical performance in reducing fracture risk in the spine and hip, Reclast, given once a year, requires an intravenous infusion, more complex than an injection, with many doctors ill- equipped to offer, making Denosumab the second choice after a pill. 

The drug targets a protein involved with bone-destroying cells called osteoclasts that diminish bone tissue by removing its mineralized matrix. Osteoclasts and osteoblasts play a major role in controlling the amount of bone tissue: osteoclasts reabsorb bone, osteoblasts are bone builders. New osteoporosis drugs, Denosumab and Odanacatiba aim at rebalancing bone loss and bone building, to help the two processes stay in balance.

About 10-million Americans, mainly post-menopausal women, suffer from osteoporosis and more than 30-million have low bone mass, which puts them at risk of developing the disease. There are approximately 200-million people affected by low bone density or osteoporosis world-wide. .