Osteo Update

Effects of long-term strontium ranelate treatment on the risk of nonvertebral and vertebral fractures in postmenopausal osteoporosis Reginster J-Y et al

Arthritis & Rheumatism 2008; 58(6):1687-1695

The TReatment Of Peripheral OSteoporosis (TROPOS) trial was primarily designed to investigate the long-term effects of strontium ranelate (Protelos®) in reducing the risk of non-vertebral fractures in postmenopausal osteoporosis (although vertebral fractures were investigated as a secondary endpoint). Of the 5,091 patients randomised, 2,714 completed the study up to 5 years. Results, at 5 years, showed that patients receiving strontium ranelate (2g/day) had a 15% reduction in risk of non-vertebral fractures compared with placebo (relative risk 0.85 [95% confidence interval 0.73-0.99]). The risk of hip fracture was decreased by 43% (relative risk 0.57 [95% confidence interval 0.33-0.97]), and the risk of vertebral fractures was decreased by 24% in the strontium ranelate group (relative risk 0.76 [95% confidence interval 0.65-0.88]).

These findings indicate that strontium ranelate results in a sustained reduction in the incidence of osteoporotic non-vertebral fractures, including hip fractures, and vertebral fractures over 5 years.

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Strontium ranelate reduces the risk of vertebral fracture in young postmenopausal women with severe osteoporosis Roux C et al

Annals of the Rheumatic Diseases 2008;67:1736-1738

The Spinal Osteoporosis Therapeutic Intervention (SOTI) was an international, double blind, placebo controlled trial, supporting the efficacy of strontium ranelate 2g/day in reducing the risk of vertebral fractures in postmenopausal women with osteoporosis and a prevalent vertebral fracture. 353 of these randomly assigned women were included in this analysis. Over 4 years, strontium ranelate significantly reduced the risk of vertebral fracture by 35% (relative risk 0.65; 95% CI 0.42 to 0.99, p<0.05). In the strontium ranelate group, the bone mineral density increased from baseline by 15.8% at lumbar spine and 7.1% at femoral neck. These data demonstrate a significant vertebral antifracture efficacy of strontium ranelate in young postmenopausal women aged 50–65 years with severe osteoporosis and confirm the efficacy of this antiosteoporotic treatment to prevent vertebral fractures, whatever the age of the patient.

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Strontium ranelate: Long-term efficacy over 8 years efficacy on vertebral and non-vertebral fractures in post-menopausal osteoporotic women Reginster J-Y et al

Presented at the European Congress on Clinical and Economic aspects of Osteoporosis (ECCEO), April 2008.

Two double blind placebo-controlled studies included a total of 6,740 Caucasian women with postmenopausal osteoporosis. In Spinal Osteoporosis Therapeutic Intervention (SOTI), patients were randomly assigned to receive strontium ranelate (2g/day) or placebo for 4 years and during the 5th year, half of the strontium ranelate (SR) group continued with SR. In the TReatment Of Peripheral OSteoporosis (TROPOS) trial, patients were randomly assigned to receive SR 2g/day or placebo for 5 years. Both studies were extended by a 3-year open label extension study to assess the efficacy of a 2g/day SR administration over 8 years.

Year-on-year increases in Bone Mineral Density (BMD) at both lumbar and femoral neck sites were demonstrated. Over the 8-year follow-up, the mean changes in BMD were 0.204±0.140g/cm2 and 0.057±0.067g/cm2 at lumbar and femoral neck sites respectively. Over the 3-year extension period, the mean change in lumbar BMD was 0.041±0.078g/cm2 representing an increase of 4.47±8.44%. The lumbar BMD increase remained significant (p<0.001) over the entire 8-year period.

The cumulative incidence of new vertebral fractures over the 3-year extension was 13.7%, as compared to 11.5% during SOTI/TROPOS first 3 years. The cumulative incidence of new osteoporotic non-vertebral fractures over the additional 3 years was 11.9% in patients from TROPOS in comparison with 9.6% during TROPOS first 3 years. The number of vertebral and non-vertebral fractures experienced over the 3-year extension was not significantly different (p=0.94) from that observed over the first 3 years in SOTI/TROPOS patients treated with SR despite an increased fracture risk with ageing.

There was no significant difference in the incidence of fractures during the extension phase compared with the first three years of the studies, confirming the sustained efficacy of strontium ranelate over time on vertebral and non-vertebral fractures.