Long-term treatment of postmenopausal women with strontium ranelate: results at 10 years

Postmenopausal osteoporosis is a chronic disease requiring long-term treatment. Strontium ranelate 2 g/day has proven efficacy against vertebral and non-vertebral (including hip) fractures over 5 years in postmenopausal women. This study [1] presents efficacy results over 10 years. The two double-blind placebo-controlled phase III studies SOTI and TROPOS included a total of 6740 Caucasian women with postmenopausal osteoporosis. Patients having participated in both studies up to 5 years were invited to enter a 3-year open-label extension study, subsequently extended by 2 years, and then received strontium ranelate up to 10 years.

At SOTI and TROPOS baseline, patients continuously treated with strontium ranelate for 10 years (n= 233) had a profile similar to that of the whole population, with a mean (SD) age of 72.0(5.5) years, and a mean (SD) lumbar spine and femoral neck BMD T-score of –3.30(1.38) and –2.95(0.57), respectively. Over the 10-year period, lumbar BMD increased continuously and significantly (P<0.05 up to year 10) with, at 10 years, a relative change from baseline of 34.5%±20.2%. At the femoral neck and total hip sites, the BMD increased significantly with a relative change from baseline of 10.7%±12.1% and 11.7%±13.6%, respectively. The incidences of fracture over the 5 years of SOTI/TROPOS and the 5 years of their extension were compared. The cumulative incidences of new vertebral and non-vertebral fractures (20.6% and 13.7%, respectively) over the 5-year extension were not statistically different from the cumulative incidences over the 5 years in the original studies (18.5% and 12.9%, respectively), despite a theoretical increase in fracture risk with aging. These results are in favour of the maintenance of the efficacy of strontium ranelate over 10 years. Strontium ranelate remained safe and well tolerated over 10 years with no unexpected adverse events.

These results suggest that the efficacy of strontium ranelate is maintained over 10 years, with a good safety profile.

1. Reginster JY, et al. Osteoporos Int. 2010;21(Suppl.5):S665-S666 (Abstract OC4)