A new approach to treating osteoporosis can significantly lower the risk of fracture among high-risk patients with osteoporosis, researchers say.
In a two-year trial, patients were treated with a novel bone anabolic medication (which builds bone mass) followed by an antiresorptive agent (which maintains bone mass).
Researchers recruited 4,093 post-menopausal women with osteoporosis and a fragility fracture and randomly assigned them to one of two groups. The first received romosozumab for a year, a new monoclonal antibody against sclerostin that rapidly builds bone mass by increasing bone formation and decreasing bone resorption. This was followed by alendronate, an antiresorptive agent commonly used as first-line therapy for osteoporosis, which maintains existing levels of bone mass. The second group received only alendronate.
Results showed that the women who received romosozumab followed by alendronate had a 48% lower rate of new vertebral fractures when compared with those who only received alendronate. Moreover, the former group had a 19% lower risk of nonvertebral fractures, and 38% lower risk of hip fracture than those in the latter group.
“Keeping patients at a constant bone mass isn’t adequate when they are already suffering from osteoporosis and their bones aren’t strong enough to resist fracture,” said Dr Andrew Karaplis, a Professor of Medicine at McGill University who treats osteoporotic patients at the Jewish General Hospital, one of the centres participating in the clinical trial.
He characterised the study as a “significant breakthrough” in treating the condition.
However, the researchers also highlighted a safety concern that emerged in the first year of the trial, with serious cardiovascular events observed more frequently in the romosozumab-alendronate group (2.5% of patients, as compared with 1.9% in the alendronate only group).
“Although the numbers are relatively small, this is a signal that requires further clarification,” Dr Karaplis said. “There exist theoretical considerations that sclerostin inhibition is associated with cardiovascular risk. Alternatively, alendronate could be cardioprotective as shown in some studies. So, we need to look more deeply as to the cause of the observed imbalance in cardiovascular events and be cautious about the patients we choose to treat with romosozumab, at least for now.”
The findings have been published in the New England Journal of Medicine.