Amgen has presented more promising late-stage data on its investigational compound denosumab which shows that the monoclonal antibody reduced the incidence of fractures in postmenopausal women.

The three-year Phase III study saw 7,800 women with osteoporosis randomly assigned either a subcutaneous injection of denosumab once every six months or placebo. The findings demonstrated that patients on the Amgen drug achieved a statistically significant reduction in the incidence of new vertebral, as well as non-vertebral and hip fractures, compared to placebo. Full details of the study are expected to be presented at the meeting of the American Society of Bone and Mineral Research in September.

Amgen noted that the compound is the first monoclonal antibody in late-stage testing that targets the RANK ligand, an essential regulator of osteoclasts, and Roger Perlmutter, executive vice president of R&D said the findings "demonstrate that denosumab treatment both increased bone mass and reduced the risk of skeletal fractures in women with postmenopausal osteoporosis”. He added that the firm is “encouraged by the magnitude and consistency of the treatment effect and pleased with the safety results”.

The importance of denosumab to Amgen is considerable given the effect that regulatory and reimbursement changes have had on sales of its anaemia drugs Epogen (epoetin alfa) and Aranesp (darbepoetin alfa). Investors were pleased with the new data and the stock rose almost 14% after the close of trading on Friday.

Still waiting on Nplate
The news came as a boost to Amgen which had earlier noted that the US Food and Drug Administration had missed its deadline of July 23 for a decision on whether to approve Nplate (romiplostim) for the treatment of thrombocytopenia in adult patients with chronic immune thrombocytopenic purpura.

The firm said it expects a final decision soon, but is not speculating on the timing of the FDA's response.