The effects of strontium ranelate on the risk of vertebral fracture in women with postmenopausal osteoporosis. Strontium ranelate reduces the risk of nonvertebral fractures in postmenopausal women with osteoporosis: Treatment of Peripheral Osteoporosis (TROPOS) study. Strontium ranelate: dose-dependent effects in established postmenopausal vertebral osteoporosis--a 2-year randomized placebo controlled trial. Prevention of early postmenopausal bone loss by strontium ranelate: the randomized, two-year, double-masked, dose-ranging, placebo-controlled PREVOS trial.
Osteoporotic structural damage and bone fragility result from reduced bone formation and increased bone resorption. In a phase 2 clinical trial, strontium ranelate, an orally active drug that dissociates bone remodeling by increasing bone formation and decreasing bone resorption, has been shown to reduce the risk of vertebral fractures and to increase bone mineral density.
                To evaluate the efficacy of strontium ranelate in preventing vertebral fractures in a phase 3 trial, we randomly assigned 1649 postmenopausal women with osteoporosis (low bone mineral density) and at least one vertebral fracture to receive 2 g of oral strontium ranelate per day or placebo for three years. We gave calcium and vitamin D supplements to both groups before and during the study. Vertebral radiographs were obtained annually, and measurements of bone mineral density were performed every six months.
                New vertebral fractures occurred in fewer patients in the strontium ranelate group than in the placebo group, with a risk reduction of 49 percent in the first year of treatment and 41 percent during the three-year study period (relative risk, 0.59; 95 percent confidence interval, 0.48 to 0.73). Strontium ranelate increased bone mineral density at month 36 by 14.4 percent at the lumbar spine and 8.3 percent at the femoral neck (P<0.001 for both comparisons). There were no significant differences between the groups in the incidence of serious adverse events.
                Treatment of postmenopausal osteoporosis with strontium ranelate leads to early and sustained reductions in the risk of vertebral fractures.
                Copyright 2004 Massachusetts Medical Society Strontium ranelate, a new oral drug shown to reduce vertebral fracture risk in postmenopausal women with osteoporosis, was studied in the Treatment of Peripheral Osteoporosis (TROPOS) study to assess its efficacy and safety in preventing nonvertebral fractures also.
                Strontium ranelate (2 g/d) or placebo were randomly allocated to 5091 postmenopausal women with osteoporosis in a double-blind placebo-controlled 5-yr study with a main statistical analysis over 3 yr of treatment.
                In the entire sample, relative risk (RR) was reduced by 16% for all nonvertebral fractures (P = 0.04), and by 19% for major fragility fractures (hip, wrist, pelvis and sacrum, ribs and sternum, clavicle, humerus) (P = 0.031) in strontium ranelate-treated patients in comparison with the placebo group. Among women at high risk of hip fracture (age > or = 74 yr and femoral neck bone mineral density T score < or = -3, corresponding to -2.4 according to NHANES reference) (n = 1977), the RR reduction for hip fracture was 36% (P = 0.046). RR of vertebral fractures was reduced by 39% (P < 0.001) in the 3640 patients with spinal x-rays and by 45% in the subgroup without prevalent vertebral fracture. Strontium ranelate increased bone mineral density throughout the study, reaching at 3 yr (P < 0.001): +8.2% (femoral neck) and +9.8% (total hip). Incidence of adverse events (AEs) was similar in both groups.
                This study shows that strontium ranelate significantly reduces the risk of all nonvertebral and in a high-risk subgroup, hip fractures over a 3-yr period, and is well tolerated. It confirms that strontium ranelate reduces vertebral fractures. Strontium ranelate offers a safe and effective means of reducing the risk of fracture associated with osteoporosis. The aim of the strontium ranelate (SR) for treatment of osteoporosis (STRATOS) trial was to investigate the efficacy and safety of different doses of SR, a novel agent in the treatment of postmenopausal osteoporosis. A randomized, multicenter, double-blind, placebo-controlled trial was undertaken in 353 osteoporotic women with at least one previous vertebral fracture and a lumbar T-score <-2.4. Patients were randomized to receive placebo, 0.5 g, 1 g, or 2 g SR/d for 2 yr. The primary efficacy endpoint was lumbar bone mineral density (BMD), assessed by dual-energy x-ray absorptiometry. Secondary outcome measures included femoral BMD, incidence of new vertebral deformities, and biochemical markers of bone metabolism. Lumbar BMD, adjusted for bone strontium content, increased in a dose-dependent manner in the intention-to-treat population: mean annual slope increased from 1.4% with 0.5 g/d SR to 3.0% with 2 g/d SR, which was significantly higher than placebo (P < 0.01). There was a significant reduction in the number of patients experiencing new vertebral deformities in the second year of treatment with 2 g/d SR [relative risk 0.56; 95% confidence interval (0.35; 0.89)]. In the 2 g/d group, there was a significant increase in serum levels of bone alkaline phosphatase, whereas urinary excretion of cross-linked N-telopeptide, a marker of bone resorption, was lower with SR than with placebo. All tested doses were well tolerated; the 2 g/d dose was considered to offer the best combination of efficacy and safety. In conclusion, SR therapy increased vertebral BMD and reduced the incidence of vertebral fractures. Early postmenopausal women ( n = 160) were randomised to receive placebo or strontium ranelate (SR) 125 mg/day, 500 mg/day or 1 g/day for 2 years (40 participants per group). All participants received calcium 500 mg/day. The primary efficacy parameter was the percent variation in lumbar bone mineral density (BMD), measured using dual-energy X-ray absorptiometry. Secondary efficacy criteria included hip BMD and biochemical markers of bone turnover. At month 24, SR 1 g/day significantly increased lumbar BMD compared with placebo [mean (SD) +5.53% (5.12); p<0.001] for measured values and [mean (SD) +1.41% (5.33%); p<0.05] for values adjusted for bone strontium content. The annual increase for adjusted values was +0.66% compared with -0.5% with placebo, with an overall beneficial effect after 2 years of about 2.4% with SR 1 g/day relative to placebo. There were no other significant between-group differences in adjusted lumbar BMD. Femoral neck and total hip BMD were also significantly increased at month 24 with SR 1 g/day compared with placebo [mean (SD): +2.46% (4.78) and +3.21% (4.68), respectively; both p<0.001)]. SR 1 g/day significantly increased bone alkaline phosphatase at all time points ( p<0.05) compared with baseline and between-group analysis showed a significant increase, compared with placebo, at month 18 ( p = 0.048). No effect on markers of bone resorption was observed. SR was as well tolerated as placebo. The minimum does at which SR is effective in preventing bone loss in early postmenopausal non-osteoporotic women is therefore 1 g/day.
There is silver level evidence (www.cochranemsk.org) to support the efficacy of strontium ranelate for the reduction of fractures (vertebral and to a lesser extent, non-vertebral) in postmenopausal osteoporotic women and an increase in BMD in postmenopausal women with/without osteoporosis. Diarrhea may occur, however, adverse events leading to study withdrawal were not significantly increased. Potential vascular and neurological side-effects need to be further explored.