Amgen's bone blockbuster

Amgen has announced favorable results for its experimental osteoporosis drug Denosumab that suggest it could take on market leader Fosamax, Merck's successful small-molecule drug. In phase 3 trials, Denosumab reduced by two-thirds the instance of spine fractures in postmenopausal women with osteoporosis. If the US Food and Drug Administration gives Amgen of Thousand Oaks, California, the green light to market, Denosumab will vie for a share of the market dominated by Whitehouse Station, New Jersey–based Merck and worth nearly $2 billion in 2007. Denosumab is touted as the blockbuster drug that could turn around Amgen's fading fortunes following safety concerns over its anemia drugs (Nat. Biotechnol. 26, 361–363, 2008). The drug, a fully human monoclonal antibody (mAb) that regulates bone-destroying osteoclasts, achieved higher bone mineral density gains than Fosamax (alendronate) in head-to-head trials. Side-effect profiles may favor Denosumab, as the mAb does not linger in the body once treatment is stopped, unlike bisphosphonates such as Fosamax that bind to the bone. Patients have also expressed a preference for twice-yearly antibody injections over weekly oral Fosamax. But Christopher Raymond, a market analyst for Milwaukee, Wisconsin–based Robert W. Baird & Co., says: “Nobody argues that D-mab has a lot of promise and probably will be a very good product. It's just it might not be enough for Amgen.” Denosumab is currently under investigation as a therapy for other conditions that reduce bone density, including rheumatoid arthritis and breast cancer.


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Birch, H. Amgen's bone blockbuster. Nat Biotechnol 26, 1206 (2008).

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