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Concept: Strontium ranelate


BACKGROUND: Strontium ranelate is currently used for osteoporosis. The international, double-blind, randomised, placebo-controlled Strontium ranelate Efficacy in Knee OsteoarthrItis triAl evaluated its effect on radiological progression of knee osteoarthritis. METHODS: Patients with knee osteoarthritis (Kellgren and Lawrence grade 2 or 3, and joint space width (JSW) 2.5-5 mm) were randomly allocated to strontium ranelate 1 g/day (n=558), 2 g/day (n=566) or placebo (n=559). The primary endpoint was radiographical change in JSW (medial tibiofemoral compartment) over 3 years versus placebo. Secondary endpoints included radiological progression, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and knee pain. The trial is registered (ISRCTN41323372). RESULTS: The intention-to-treat population included 1371 patients. Treatment with strontium ranelate was associated with smaller degradations in JSW than placebo (1 g/day: -0.23 (SD 0.56) mm; 2 g/day: -0.27 (SD 0.63) mm; placebo: -0.37 (SD 0.59) mm); treatment-placebo differences were 0.14 (SE 0.04), 95% CI 0.05 to 0.23, p<0.001 for 1 g/day and 0.10 (SE 0.04), 95% CI 0.02 to 0.19, p=0.018 for 2 g/day. Fewer radiological progressors were observed with strontium ranelate (p<0.001 and p=0.012 for 1 and 2 g/day). There were greater reductions in total WOMAC score (p=0.045), pain subscore (p=0.028), physical function subscore (p=0.099) and knee pain (p=0.065) with strontium ranelate 2 g/day. Strontium ranelate was well tolerated. CONCLUSIONS: Treatment with strontium ranelate 1 and 2 g/day is associated with a significant effect on structure in patients with knee osteoarthritis, and a beneficial effect on symptoms for strontium ranelate 2 g/day.

Concepts: Knee, Joint, Acupuncture, Strontium ranelate


The objective was to undertake a health economic analysis of denosumab for the treatment of osteoporosis in women from the UK, using the FRAX® tool. Denosumab was cost-effective in women with a risk of major osteoporotic fracture meeting or exceeding approximately 20 % who are unable to take, comply with or tolerate generic alendronate. INTRODUCTION: Denosumab is a novel biologic agent developed for the treatment of osteoporosis, which has been shown to reduce the risk of fractures in a phase-III trial. The objective of the present study was to undertake a health economic analysis of denosumab in women from the UK. Ten-year probabilities of a major osteoporotic fracture at which denosumab is a cost-effective alternative to no treatment, generic alendronate, risedronate and strontium ranelate were estimated. METHODS: A previously published Markov model was adapted to incorporate fracture and mortality risk assessments based on absolute fracture probability, as estimated by FRAX®. The model included treatment persistence and residual effect after discontinuation. RESULTS: At a willingness-to-pay (WTP) of £30,000 per quality-adjusted life year and a 10-year fracture probability equivalent to a woman with a prior fragility fracture, denosumab was cost-effective compared to no treatment from the age of 70 years. At the same WTP, denosumab was-irrespective of age-cost-effective compared to no treatment at a major osteoporotic fracture probability of approximately 20 %. Denosumab was estimated to cost-effectively replace strontium, risedronate and generic alendronate at 10-year probabilities exceeding 11, 19 and 32 %, respectively. CONCLUSION: FRAX® facilitates the estimation of cost-effectiveness-based intervention thresholds applicable to patients with different combinations of clinical risk factors, which more closely matches the situation in clinical practice. Denosumab is cost-effective in patients with major osteoporotic fracture probabilities meeting or exceeding approximately 20 % who are unable to take, comply with or tolerate generic alendronate.

Concepts: Osteoporosis, Health economics, Risk, Cost-effectiveness analysis, Estimation, Cost-utility analysis, Cost-Effectiveness Analysis Registry, Strontium ranelate


Strontium ranelate is an approved pharmacotherapy for osteoporosis in Europe and Australia, but not in Canada or the United States. Strontium citrate, an alternative strontium salt, however, is available for purchase over-the-counter as a nutritional supplement. The effects of strontium citrate on bone are largely unknown. The study’s objectives were 1) to quantify bone strontium accumulation in female Sprague Dawley rats administered strontium citrate (N=7) and compare these levels to rats administered strontium ranelate (N=6) and vehicle (N=6) over 8weeks, and 2) to verify an in vivo X-ray fluorescence spectroscopy (XRF) system for measurement of bone strontium in the rat. Daily doses of strontium citrate and strontium ranelate were determined with the intention to achieve equivalent amounts of elemental strontium. However, post-hoc analyses of each strontium compound conducted using energy dispersive spectrometry microanalysis revealed a higher elemental strontium concentration in strontium citrate than strontium ranelate. Bone strontium levels were measured at baseline and 8weeks follow-up using a unique in vivo XRF technique previously used in humans. XRF measurements were validated against ex vivo measurements of bone strontium using inductively coupled plasma mass spectrometry. Weight gain in rats in all three groups was equivalent over the study duration. A two-way ANOVA was conducted to compare bone strontium levels amongst the three groups. Bone strontium levels in rats administered strontium citrate were significantly greater (p<0.05) than rats administered strontium ranelate and vehicle. ANCOVA analyses were performed with Sr dose as a covariate to account for differences in strontium dosing. The ANCOVA revealed differences in bone strontium levels between the strontium groups were not significant, but that bone strontium levels were still very significantly greater than vehicle.

Concepts: Fluorescence, Spectroscopy, X-ray fluorescence, Strontium, In vivo, Rat, Laboratory rat, Strontium ranelate


Low persistence with osteoporosis medication is associated with higher fracture risk. Previous studies estimated that 1-year persistence with osteoporosis medication is low. Our aim was to study persistence with osteoporosis medication among patients with long-term follow-up (to 5 years). The InterAction Database (IADB) was used to analyze persistence of 8610 Dutch patients initiating osteoporosis drugs between 2003 and 2011. Drugs under study were alendronate, risedronate, ibandronate, etidronate, raloxifene and strontium ranelate. Cumulative persistence rates were calculated after different time frames (3 months-5 years) using survival analysis. Multivariate Cox proportional hazard analyses were used to identify determinants of non-persistence. Furthermore, switching rates of persistent patients who initiated bisphosphonate therapy were analyzed. Persistence with osteoporosis therapy was 70.7 % (95 % CI, 69.7-71.7), 58.5 % (95 % CI, 57.4-59.6 %), 25.3 % (95 % CI, 24.1-26.5) after 6 months, 1 and 5 years, respectively. Determinants associated with higher risk to non-persistence within the first year were daily dosing regimen [HR, 1.76 (95 % CI, 1.46-2.14)], age <60 years [HR, 1.26 (95 % CI, 1.19-1.34)] and use of glucocorticoids [HR, 1.16 (95 % CI, 1.07-1.26)]. Monthly dosing schedule and use of generic brands of alendronate did not show a significant association with non-persistence. Approximately 4.0 % of patients initiating therapy with weekly alendronate or weekly risedronate switched therapy. Persistence with osteoporosis medication is low. Because low persistence is strongly associated with higher fracture risk, interventions to improve persistence are recommended. This study identified several patient groups in whom such interventions may be most relevant.

Concepts: Bisphosphonate, Osteoporosis, Bisphosphonates, Strontium, Proportional hazards models, Initiation, Approximation, Strontium ranelate


This study was designed to compare the effects of alendronate (ALN), strontium ranelate (SR), and zoledronic acid (ZOL) on bone-implant osseointegration in ovariectomized rats. Histological examination and biomechanical tests show that ZOL, ALN, and SR enhance bone-implant osseointegration; ALN and SR have similar effects, while ZOL enhances bone-implant osseointegration more than ALN and SR INTRODUCTION: This study aims to compare the effects of ALN, SR, and ZOL on bone-implant osseointegration in ovariectomized rats. METHODS: Sixty female Sprague-Dawley rats were included in this study. Of them, 48 rats were ovariectomized (OVX) and assigned to four groups: OVX (OVX + Veh), ALN (OVX + ALN), SR (OVX + SR), and ZOL (OVX + ZOL). And another 12 rats were sham-operated as a control group (Sham). Four weeks after ovariectomy, HA-coated titanium implants were inserted into the tibias bilaterally in all rats. Then the rats in groups ALN, SR, and ZOL were systemically administrated with alendronate (7 mg/kg/week, orally), strontium ranelate (500 mg/kg/day, orally), or a single injection of zoledronic acid (0.1 mg/kg, iv), respectively. Twelve weeks after implantation, all rats were sacrificed to get the femurs and tibias. Histological examination and biomechanical tests were used to evaluate bone-implant osseointegration in all groups. RESULTS: ALN, SR, and ZOL significantly increased distal femoral BMD when compared with group OVX; ZOL increased BMD significantly more than ALN and SR (P < 0.05). Significant increase of bone-to-implant contact and peri-implant bone fraction were observed in groups ALN, SR, and ZOL when compared with group OVX (P < 0.05). Groups ALN and SR were inferior to groups ZOL and Sham (P < 0.05) in bone-to-implant contact and peri-implant bone fraction. Similar results were found in biomechanical testing (max pushout force). CONCLUSIONS: In rats losing bone rapidly after ovariectomy, systemic administration of ZOL, ALN, and SR causes better bone-implant osseointegration when compared to OVX; ALN and SR have similar positive effects on osseointegration, while ZOL, that was given in a dose with more positive BMD effect than that of ALN or SR, causes better osseointegration than either ALN or SR.

Concepts: Strontium, Histology, Dental implant, Strontium ranelate


We have reviewed 47 drug rash with eosinophilia and systemic symptoms (DRESS) cases associated to strontium ranelate reported up to March 2011 to the Marketing Holder. The main signs were skin rash, fever, face oedema hypereosinophilia and liver involvement. For ten patients, persistence of DRESS symptoms was reported at the latest news obtained, and DRESS was identified as the direct cause of death in one case. The maximum incidence of DRESS associated with strontium ranelate was 1/24,112 [95 % CI (1/14,859; 1/42,194)] newly treated patients in France. Because DRESS is a severe drug reaction, the occurrence of a rash in a patient treated with strontium ranelate should lead to prompt and permanent treatment discontinuation. INTRODUCTION: This study aims to describe cases of DRESS reported to the Marketing Authorisation Holder worldwide for patients receiving strontium ranelate by practitioner or by regulatory authorities. METHODS: Spontaneously reported hypersensitivity events from the strontium ranelate pharmacovigilance database since marketing authorisation (2004) to March 2011 were reviewed by an expert committee. Cases of DRESS were classified as established, probable, possible or no DRESS according to expert judgement. National incidences of DRESS were estimated in relation to the number of newly treated patients. RESULTS: Up to March 2011, 325 cases of strontium ranelate-induced hypersensitivity events were assessed from which 47 DRESS cases were confirmed. Mean age was 68.7 years and besides skin rash, the main signs and symptoms were hypereosinophilia, liver involvement, fever and face oedema. Median time to skin reaction was 33.5 days after treatment start. Most patients (62 %) recovered at the time of reporting or were recovering. For ten patients, persistence of DRESS symptoms was reported at the latest news obtained. Relapses were observed in a single case. The mortality rate was 8.5 %. The maximum incidence of DRESS associated with strontium ranelate was 1/24,112 [95 % CI (1/14,859; 1/42,194)] newly treated patients in France. CONCLUSION: DRESS is a well-identified and characterised adverse reaction to strontium ranelate. This risk should be integrated in the risk-benefit balance evaluation of patient treatment, and the occurrence of a rash should lead to prompt and permanent treatment discontinuation with careful follow-up.

Concepts: Pharmacology, Mortality rate, Medical terms, Median, Adverse drug reaction, Medical sign, Strontium ranelate, Rash


Osteoarthritis is a primary cause of disability and functional incapacity. Pharmacological treatment is currently limited to symptomatic management, and in advanced stages, surgery remains the only solution. The therapeutic armamentarium for osteoarthritis remains poor in treatments with an effect on joint structure, that is, disease-modifying osteoarthritis drugs (DMOADs). Glucosamine sulfate and chondroitin sulfate are the only medications for which some conclusive evidence for a disease-modifying effect is available. Strontium ranelate is currently indicated for the prevention of fracture in severe osteoporosis. Its efficacy and safety as a DMOAD in knee osteoarthritis has recently been explored in the SEKOIA trial, a 3-year randomized, double-blind, placebo-controlled trial. Outpatients with knee osteoarthritis, Kellgren and Lawrence grade 2 or 3, and joint space width (JSW) of 2.5-5 mm received strontium ranelate 1 g/day (n = 558) or 2 g/day (n = 566), or placebo (n = 559). This sizable population was aged 62.9 years and had a JSW of 3.50 ± 0.84 mm. Treatment with strontium ranelate led to significantly less progression of knee osteoarthritis: estimates for annual difference in joint space narrowing versus placebo were 0.14 mm [95% confidence interval (CI) 0.05-0.23 mm; p < 0.001] for 1 g/day and 0.10 mm (95% CI 0.02-0.19 mm; p = 0.018) for 2 g/day, with no difference between strontium ranelate groups. Radiological progression was less frequent with strontium ranelate (22% with 1 g/day and 26% with 2 g/day versus 33% with placebo, both p < 0.05), as was radioclinical progression (8% and 7% versus 12%, both p < 0.05). Symptoms also improved with strontium ranelate 2 g/day only in terms of total WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score (p = 0.045), and its components for pain (p = 0.028) and physical function (p = 0.099). Responder analyses using a range of criteria for symptoms indicated that the effect of strontium ranelate 2 g/day on pain and physical function was clinically meaningful. Strontium ranelate was well tolerated. The observation of both structure and symptom modification with strontium ranelate 2 g/day makes SEKOIA a milestone in osteoarthritis research and treatment.

Concepts: Osteoporosis, Chondroitin sulfate, Glucosamine, Osteoarthritis, Knee, Joint, Glycosaminoglycan, Strontium ranelate


1. Pharmacokinetics of exogenous Sr and bioequivalence of a new oral formulation of strontium ranelate compared with the brand-name drug in healthy Chinese subjects was evaluated. 2. A balanced, randomized, single-dose, 2-treatment parallel study was conducted in 36 healthy Chinese subjects. Subjects were randomly allocated into two groups of 18 to receive a single oral dose of test formulation and reference formulation under a fasting state, respectively. Blood samples were collected at 19 designated time points up to 240 h post-dose. Serum concentrations of Sr were quantified by ICP-MS. 3. A total of 36 subjects were enrolled and completed the study. 9 mild adverse events in 6 subjects were reported. The Cmax, AUC0-72 h, AUC0-t, and AUC0-∞ of test and reference formulations shown as mean ± SD were 6.97 ± 1.78 and 6.78 ± 1.80 µg/mL, 199 ± 51 and 187 ± 38 µg·h/mL, 303 ± 89 and 278 ± 54 µg·h/mL, and 337 ± 109 and 305 ± 60 µg·h/mL, respectively. 4. Two formulations were bioequivalent, and both were generally well tolerated.

Concepts: Pharmacology, Strontium, Randomness, Pharmacokinetics, Bioavailability, Bioequivalence, Strontium ranelate, Formulation


Recently, the use of the pharmacological agents strontium ranelate (SR), parathyroid hormone (1-34, PTH) and zoledronic acid (ZA) has come to prominence for the treatment of osteoporosis due to their ability to prevent bone loss in osteoporotic patients. Although much emphasis has been placed on using pharmacological agents for the prevention of disease, much less attention has been placed on which one is more effective. There is still no direct comparative study on these three drugs. The aim of the present study was to investigate the effect of SR, PTH, ZA on preventing ovariectomy-induced osteoporosis in rats. After bilateral ovariectomy the rats randomly received vehicle, SR (500 mg/kg body weight/day, orally), PTH (20 μg/kg/day, subcutaneously) or a single injection of ZA (0.1 mg/kg, i.v.) until death at 12 weeks. The distal femurs were harvested for evaluation of bone metabolism. The rats treated with ZA demonstrated the highest levels of new bone formation as assessed by microcomputed tomography (CT), biomechanical strength, histological analysis and bone metabolism. Furthermore, PTH and SR showed a stronger effect on improving trabecular bone mass at 12 weeks. The results from the present study demonstrate that systemic administration of PTH, SR and ZA could prevent bone loss, while a single dose of ZA has a better effect on preventing ovariectomy-induced osteoporosis than either PTH or SR.

Concepts: Osteoporosis, Bone, Vitamin D, Calcitonin, Skeletal system, Osteoclast, Hyperparathyroidism, Strontium ranelate


An investigation of bone samples taken from the left ulna of New Zealand white rabbits, with and without stresses and hysteresis loop, was undertaken using Small Angle X-ray Scattering technique. The purpose of this study is to investigate the nanostructural changes in the mean size of hydroxyapatite crystals thickness (T) during different mechanical conditions. The experiments were performed using bone samples aged 2 and 4 weeks, with and without strontium ranelate treatment, after compressive load and hysteresis loop. We did not observe any clear effects of strontium ranelate on the bones since the MANOVA test for epiphysis and diaphysis were found. On the other hand, a significant difference appears in epiphysis between 2 and 4 weeks. Furthermore, a reduction in the mean size of hydroxyapatite crystal thickness was observed when the loading pressure force increased, due to the buckling phenomenon. A return of memory points in the elastic region of the bone was observed. The significance of these results lays on the development of nanoproducts, with properties that are closer to the actual bone structure.

Concepts: Bone, Fundamental physics concepts, Statistical significance, Observation, Hypothesis, Materials science, Phenomenon, Strontium ranelate