France’s Servier says that the osteoporosis treatment Protelos significantly improves bone structure in postmenopausal women when compared to the bisphosphonate alendronate, according to results of the first head-to-head study of the two drugs.

The study, which was recently released in Osteoporosis International, showed that Protelos (strontium ranelate) increased cortical bone thickness, bone volume and trabecular bone density to a significantly greater extent than alendronate over a one-year period. The two-year double-blind study included 88 women over the age of 50 with postmenopausal osteoporosis who were randomised to treatment with either Protelos 2g daily or alendronate 70mg per week.

The one-year interim results on bone microstructure showed a significant 5.3% increase in cortical thickness, and a significant 2.0% increase in bone volume in the Protelos-treated group, whereas there was no change in the alendronate group. Servier says the results are due to the different mechanisms of action of the two agents as alendronate only inhibits the resorption of bone, whereas Protelos also increases bone formation.

"These results are highly interesting and important news for osteoporosis patients", said Rene Rizzoli of the Geneva University Hospital and principal investigator of the study. He added that the study suggests that with Protelos, “bone may be as good if not superior as with alendronate in women with postmenopausal osteoporosis”.