Amgen and UCB have been boosted by promising mid-stage data for their investigational osteoporosis drug romosozumab.

A Phase II trial, the results from which have been published in the New England Journal of Medicine, showed that romosozumab demonstrated a significant increase in bone mineral density. Specifically, the trial demonstrated that, compared with placebo, treatment for 12 months with the anti-sclerostin biologic significantly increased BMD at the lumbar spine, total hip and femoral neck.

Amgen and UCB noted that significant increases were also observed in the first BMD assessment at three months and moreover, in exploratory analyses, increases observed at the lumbar spine and hip "were significantly greater than those observed with current treatments", namely Merck & Co's Fosamax (alendronate) and Eli Lilly's Forteo (teriparatide).  

Iris Loew-Friedrich, chief medical officer at UCB, noted that romosozumab is designed to stimulate bone formation, "which makes it different from most available treatments that reduce bone resorption". She added that "we are encouraged by the emerging efficacy and safety profile, and look forward to further investigating its potential in the ongoing global Phase III clinical programme". Final data from the latter, which will enroll up to 10,000 patients, are expected by the end of 2015.

Sean Harper, Amgen R&D chief, noted that broken bones due to osteoporosis are common "yet the seriousness of this health event remains underappreciated, with only two in ten women receiving follow-up testing or treatment after they have broken a bone". He added that "with its bone-forming ability, romosozumab may result in new treatment strategies".

If all goes well in Phase III, many observers believe romosozumab could be a blockbuster.