The osteoporosis treatment Protelos® (strontium ranelate) significantly improved bone structure in postmenopausal women when compared to the bisphosphonate alendronate according to the results of the first head-to-head study of the two drugs(1) recently released in Osteoporosis International, the official journal of the World Congress of Osteoporosis.
The study which used a new, non-invasive technique called high-resolution computerised tomography (SCANCO device), showed that Protelos increased cortical bone thickness, bone volume and trabecular bone density to a significantly greater extent than alendronate over a one-year period. These results are due to the different mechanisms of action of the two anti-osteoporotic agents. Whereas alendronate only inhibits the resorption of bone, Protelos has an innovative dual mechanism of action. Unlike bisphosphonates and other osteoporosis treatments, Protelos simultaneously increases bone formation and decreases bone resorption(2), rebalancing bone turnover in favour of the formation of new and stronger bone.
“These results are highly interesting and important news for osteoporosis patients”, points out Professor René Rizzoli, the principal investigator of the study from the Geneva University Hospital, Switzerland. “Cortical thickness is an important determinant of the strength of long bones and in the prevention of hip fractures. Bone volume and trabecular thickness relate more closely to trabecular bone, the type of bone found in the vertebra. Our study suggests that with strontium ranelate bone may be as good if not superior as with alendronate in women with postmenopausal osteoporosis.”
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, a determinant of bone strength, showed a significant +5.3% increase in cortical thickness, and a significant +2.0% increase in bone volume (BV/TV) in the Protelos treated group, whereas there was no change in the alendronate treated group.
Unrivalled efficacy against fractures
Protelos has been shown to be well-tolerated and easy-to-use for patients.(3) Protelos’ antifracture efficacy was recently highlighted in the European guidance demonstrating that Protelos has a broader range of efficacy compared to the other anti-osteoporotic agents and it has been proven to be effective in treating fractures at vertebral, nonvertebral and hip sites.(4) No other osteoporosis treatment has such long-term evidence showing efficacy in preventing fractures over 5 years.(5) This anti-fracture efficacy has also been shown to be sustained over eight years.(6)
Protelos is marketed by independent French pharmaceutical company, Servier. It is licensed for the treatment of postmenopausal osteoporosis to reduce the risk of vertebral and hip fractures. It is currently registered worldwide and launched in 72 countries.
Protelos is also sold under the trade names Protos®, Osseor®, Bivalos®, Protaxos®, Ossum®.
References
(1) Rizzoli R, Felsenberg D, Laroche M et al. Oral Communication 37:Strontium ranelate has a more positive influence than alendronate on distal tibia cortical and trabecular bone microstructure in women with postmenopausal osteoporosis. Osteoporosis International. 2009; 20:163-186(OC37)
(2) Marie PJ, Ammann P, Boivin G, et al. Mechanisms of action and therapeutic potential of strontium in bone. Calcif Tissue Int. 2001;69:121-129
(3) Protelos European Summary of Product Characteristics.
(4) Kanis JA, Burlet B, Cooper C et al. European guidance for the diagnosis and management of osteoporosis in post menopausal women. Osteoporosis International 2008; 19(4):399-428.
(5) Reginster, JY, Felsenberg D, Boonen S et al. Effects of long-term strontium ranelate on the risk of nonvertebral and vertebral fractures in postmenopausal osteoporosis: results of a five-year reandomized, placebo-controlled trial. Arthritis Rheum 2008.58:1687 - 1695
(6) Reginster JY, Sawicki A, Roces – Varela A. Strontium Ranelate: 8 years efficacy on vertebral and nonvertebral fractures in post menopausal osteoporotic women. Osteoporos Int. 2008;19(Suppl.1):S131-S132 (Abstract P311)
