Osteoporosis study: Protelos have significant bone-forming activity than bisphosphonates

Mar 25 2011

Protelos(R) (strontium ranelate) has significantly greater bone-forming activity than the commonly prescribed bisphosphonate, alendronate, according to results of the largest-ever biopsy study in post-menopausal women presented today at the European Congress on Osteoporosis and Osteoarthritis (ECCEO11-IOF) in Valencia. Through its unique dual impact on both bone formation and resorption, Protelos substantially reduces fracture risk, the primary goal of osteoporosis treatment.

Bone biopsy is the gold standard technique used to examine the effect of osteoporosis treatments on bone. Bone biopsies involve taking a cylindrical sample of real bone from the upper part of the pelvis called the iliac crest. Biopsies allow the identification of non-mineralized (osteoid tissue) and mineralized subparts of the bone matrix and can be used to measure bone formation rates and other parameters. Bone formation is measured by examining mineralizing surface, the proportion of bone surface on which new mineralized bone is being deposited.

In this international, double blind study of 268 women, Protelos has a significantly greater effect on mineralizing surface compared to alendronate. After six months, mineralizing surface, expressed as a percentage of bone surface (the study's primary endpoint) was 2.94% in Protelos patients compared to 0.20% in patients receiving alendronate (p<0.001). This superior effect on bone formation was further amplified after 12 months of treatment. Protelos also significantly increased both the bone formation rate and the mineral apposition rate compared to alendronate over six and 12 months of treatment. The superior bone-forming efficacy of Protelos is linked to its innovative dual mechanism of action which rebalances bone turnover in favour of the formation of newer and stronger bone. This is not the case with bisphosphonates as they have been shown to actually suppress the bone forming-surface.

"The results of the study show that Protelos preserves a higher bone forming activity compared with alendronate," notes study investigator Professor Roland Chapurlat from the Hôpital Edouard Herriot, Service de Rhumatologie et Pathologie Osseuse, Lyon, France.

"The bone-forming activity seen here can be attributed to strontium ranelate's unique mechanism of action which, unlike bisphosphonates that block bone resorption and formation, combines the dual effects of increasing or maintaining bone formation and decreasing bone resorption," points out study investigator Professor PG Ste- Marie from the Centre Hospitalier de l'Université de Montréal, Canada.

This new trial conducted in 268 post-menopausal women with osteoporosis is the largest biopsy study ever. It sets a new standard in the assessment of the effects of different osteoporosis treatments on bone. It is also the second head to head study in which Protelos demonstrates superiority versus alendronate. In the previous trial, which used a non-invasive technique (High Resolution peripheral Quantitative Computerized Tomography), Protelos was shown to be more effective than alendronate on bone microarchitecture at both cortical and trabecular level.

Over the course of both studies, the occurrence of adverse events was similar for each treatment group.

Anti-fracture efficacy sustained over 10 years

Better efficacy on bone formation and bone quality are the key determinants for Protelos and explain its well demonstrated efficacy against vertebral, non vertebral and hip fractures. It is also the key determinant explaining why Protelos is the unique treatment which has recently been shown to have sustained anti-fracture efficacy over 10 years, making it a first choice of treatment for postmenopausal osteoporotic women.