The effects of strontium ranelate in Asian women with postmenopausal osteoporosis

Metabolic bone disorders and the promise of marine osteoactive compounds

Metabolic bone disorders and associated fragility fractures are major causes of disability and mortality worldwide and place an important financial burden on the global health systems. These disorders result from an unbalance between bone anabolic and resorptive processes and are characterized by different pathophysiological mechanisms. Drugs are available to treat bone metabolic pathologies, but they are either poorly effective or associated with undesired side effects that limit their use. The molecular mechanism underlying the most common metabolic bone disorders, and the availability, efficacy, and limitations of therapeutic options currently available are discussed here. A source for the unmet need of novel drugs to treat metabolic bone disorders is marine organisms, which produce natural osteoactive compounds of high pharmaceutical potential. In this review, we have inventoried the marine osteoactive compounds (MOCs) currently identified and spotted the groups of marine organisms with potential for MOC production. Finally, we briefly examine the availability of in vivo screening and validation tools for the study of MOCs.

A network meta-analysis on the short-term efficacy and adverse events of different anti-osteoporosis drugs for the treatment of postmenopausal osteoporosis

A network meta-analysis was conducted to compare the short-term efficacy and adverse events of different drugs for the treatment of postmenopausal osteoporosis (PMO), providing a more effective treatment for PMO. We initially searched through various databases like PubMed, Cochrane Library, and EMBASE from inception till October 2016. All randomized controlled trials (RCTs) of drugs for the treatment of PMO were included for direct and indirect comparison. A combination of direct and indirect evidence of different inhibitors of anti-diabetic drugs for treatment of PMO were considered for calculating the weighted mean difference (WMD) value or odd ratio (OR) value and to draw surface under the cumulative ranking (SUCRA) curves. Twenty-seven RCTs were ultimately incorporated into this network meta-analysis comprising of 48 200 patients suffering from PMO. The network meta-analysis revealed that compared with placebo, alendronate had better efficacy on improving bone mineral density (BMD) at lumbar spine, femoral neck, and total hip. Risedronate and raloxifene had relatively lower incidence of new vertebral fractures. The SUCRA analysis showed that alendronate had better efficacy on improving BMD, risedronate could significantly decrease the incidence of fresh fracture and bazedoxifene was relatively safe. The available evidence suggested that alendronate and risedronate might be the superior choices for the treatment of PMO, while bazedoxifene was a comparatively safer option for patients.

Effect of OPG gene mutation on protein expression and biological activity in osteoporosis

The effect of an osteoprotegerin (OPG) gene mutation was investigated on its protein expression and biological activity in osteoporosis. The pcDNA3.0-OPG plasmid or wild-type plasmid were transfected into HEK293 cells. Osteoclast tartrate-resistant acid phosphatase (TRAP) staining and counting were then performed, and the expression of genes related to osteoclast differentiation and activation were measured by RT-PCR. The wild-type or mutant-type OPG at concentrations of 0, 10, 20, 50 and 100 ng/ml were added respectively to RAW264.7 cells and incubated for 24 h. The viability of cells treated with the wild-type and mutant-type OPG at a concentration of 100 ng/ml was still over 99%, which indicated that the wild-type and mutant-type OPG at this concentration had no cytotoxic effect on RAW264.7 cells. The number of TRAP-positive cells decreased with increasing concentration of wild-type or mutant-type OPG. At the concentrations of 20, 50 and 100 ng/ml, the inhibitory effect of wild-type OPG was significantly higher than that of mutant-type OPG (p<0.05). Both mutant-type and wild-type OPG inhibited the bone resorption activity of osteoclasts, and the inhibitory effect of wild-type OPG was significantly higher than that of mutant-type OPG at the concentrations of 20, 50 and 100 ng/ml (p<0.05). The levels of TRAP and RANK mRNA in the wild-type OPG treatment group were significantly lower than those in the control group, while the levels of TRAP and RANK mRNA in the mutant-type OPG treatment group were significantly lower than those in the wild-type group (p<0.05). The genetic mutation did not affect the protein expression levels of OPG, but inhibited the normal activity of OPG.

A comparison of adverse event and fracture efficacy data for strontium ranelate in regulatory documents and the publication record

OBJECTIVE

Recently, the European Medicines Agency reported that strontium ranelate increases myocardial infarction risk in postmenopausal women, 8.5 years after it was registered for use in osteoporosis. Unreported serious adverse events in clinical trials for other pharmaceuticals have been described in recent years. We assessed reporting of adverse events and fracture efficacy of strontium.

METHODS

We compared data on adverse effects (myocardial infarction, venous thromboembolism and pulmonary embolism) and fracture efficacy of strontium in publicly available regulatory documents with data in publications retrieved from searching PubMed.

RESULTS

We identified 5 regulatory documents and 9 primary publications of 7 randomised, placebo-controlled trials of strontium that reported relevant data. We identified several areas of concern in these reports: the increased risk of myocardial infarction with strontium was not identified in a pivotal phase 3 clinical trial despite specific regulatory review of cardiovascular events; data on myocardial infarction were not included in any primary publication; increased risks of venous thromboembolism and pulmonary embolism with strontium were not reported in either of the phase 3 clinical trials; data on venous thromboembolism were reported in only 5 of 9 primary publications, data on pulmonary embolism in only 2 of 9 primary publications, and either was discussed in <50% of subsequent review articles. There were differences in participant numbers, fracture cases and venous thromboembolism cases between regulatory documents and primary publications. Based on all available data from primary publications and regulatory documents, the number of fractures prevented by strontium use is similar to the number of extra cases of venous thromboembolism, pulmonary embolism and myocardial infarction caused by strontium use.

CONCLUSIONS

The risks of strontium use are similar to the benefits. Full disclosure of the clinical trial data and regulatory documents would allow clinicians and their patients to decide whether use of the drug is worthwhile.

Vitamin D status in non-supplemented postmenopausal Taiwanese women with osteoporosis and fragility fracture

BACKGROUND

Vitamin D is essential for calcium metabolism, Vitamin D deficiency can precipitate osteoporosis, cause muscle weakness and increase the risk of fracture. The aim of this study was to assess the prevalence of vitamin D inadequacy among non-supplemented postmenopausal women with osteoporosis and fragility fractures of the hip or vertebrae in Taiwan.

METHODS

This multi-center, cross-sectional, observational study analyzed the vitamin D inadequacy [defined as 25(OH) D level less than 30 ng/mL] in Taiwanese postmenopausal osteoporotic patients who suffered from a low trauma, non-pathological fragility hip or vertebral fracture that received post-fracture medical care when admitted to hospital or at an outpatient clinic.

RESULTS

A total of 199 patients were enrolled at 8 medical centers in Taiwan; 194 patients met the study criteria with 113 (58.2%) and 81 (41.8%) patients diagnosed with hip and vertebral fracture, respectively. The mean serum 25(OH) D level was 21.1 ± 9.3 ng/mL, resulting in a prevalence of vitamin D inadequacy of 86.6% of the patients.

CONCLUSIONS

High prevalence of vitamin D inadequacy across all age groups was found among non-supplemented women with osteoporosis and fragility hip or vertebral fracture in Taiwan.

Clinical practice guidelines for the prevention and treatment of osteoporosis in Taiwan: summary

Osteoporosis is recognized as a major public health problem worldwide and in Taiwan. However, many patients with osteoporotic fractures do not receive appropriate assessments or treatments. This guideline, proposed by the Taiwanese Osteoporosis Association, is to serve as a quick reference for healthcare providers to improve the assessment of osteoporosis and development of optimal strategies for osteoporotic management in Taiwan. To review and update osteoporosis management, the guideline is constituted with Taiwan-specific osteoporosis epidemiological data, medication protocols, and the 10-year FRAX(®). The guideline is based on evidence-based medicine and public health considerations. Recommendations are not limited to the reimbursement regulations permitted by the National Health Insurance of Taiwan.

Study on the role of zoledronic acid in treatment of postmenopausal osteoporosis women

OBJECTIVE

We aimed to assess the role of zoledronic acid (ZOL) on the risk of fracture and bone mineral density (BMD) in women with osteoporosis.

METHODS

A double-blind and placebo-controlled design was taken in our study. 327 patients who received an intravenous 5-mg infusion zoledronic acid at day 0, at 12 months were enrolled in treatment group, and the remaining 333 patients who received placebo at the same time of the treatment group were included as control group. The incidence of fracture and BMD in the femoral neck and total hip were assessed.

RESULTS

ZOL group had lower incidence of fracture at any clinical fracture, clinical vertebral fracture, non-vertebral fracture and hip fracture compared with placebo group at the time of one year and three years. We found that the BMD were significantly increased at femoral neck and total hip in ZOL group at the time of one year and three years follow-up when compared with placebo group (P<0.05). The adverse events in the ZOL within three days of drug infusion were significantly higher than the control group, but we did not find significant difference in the serious adverse effect between the two groups.

CONCLUSIONS

Zoledronic acid (ZOL) could be used as a safe and effective method for female with osteoporosis.

Randomized controlled trial of zoledronic acid for treatment of osteoporosis in women

Objective

To assess the effect of zoledronic acid (ZOL) on bone mineral density (BMD) and fracture risk at the L1–L4 vertebrae, femoral neck, hip and trochanter in Chinese women with osteoporosis.

Methods

A randomized controlled trial was conducted in female patients with osteoporosis, randomized to receive one 5-mg ZOL intravenous infusion per year or placebo equivalent. Facture risk and BMD were measured over a 2-year follow-up period.

Results

A statistically significant reduction in the risk of fracture was observed at the trochanter in the ZOL group ( n = 242) compared with the placebo group ( n = 241); (odds ratio 0.54 [95% confidence interval 0.29, 0.98]): BMD was 0.24, 0.28, 0.31 and 0.22 greater at the L1–L4 vertebrae, total hip, femoral neck and trochanter, respectively, in the ZOL group. The incidence of adverse events was comparable between treatment groups.

Conclusions

This study indicated that ZOL could increase BMD and reduce fracture risk in women with osteoporosis over a 2-year follow-up period, and was not associated with any serious drug-related adverse effects.

Alopecia associated with strontium ranelate use in a 62-year-old woman

Strontium ranelate is an effective drug that was developed for treating osteoporosis. Here, we report the case of a 62-year-old woman who developed headache and diffuse scalp hair loss 1 week after receiving strontium ranelate treatment for osteoporosis. The treatment was subsequently stopped because of the intractable headache. Nevertheless, the patient continued to lose hair for 6 weeks following treatment discontinuation. Histopathological analysis of scalp tissues revealed anagen effluvium. The patient's hair started regrowing slowly 2 months after treatment with strontium ranelate was discontinued.

Monitoring bone strontium levels of an osteoporotic subject due to self-administration of strontium citrate with a novel diagnostic tool, in vivo XRF: a case study

A previously developed in vivo X-ray fluorescence (IVXRF) I-125 based system was used to measure bone strontium levels non-invasively in an osteoporotic female volunteer. The volunteer was recruited in December 2008, as part of the Ryerson and McMaster University Strontium in Bone Research Study and measured at twice weekly, weekly and monthly intervals. Thirty minute measurements were taken at the finger and ankle bone sites, representing primarily cortical and trabecular bone, respectively and the strontium K-alpha X-ray peak at 14.16 keV was used in the analysis. Since the volunteer had no prior history of strontium based medications or supplementation, baseline natural strontium levels were obtained followed by a 24h measurement of first intake of strontium citrate supplements (680 mg Sr/day). While the baseline levels of 0.38 ± 0.05 and 0.39 ± 0.10 for the finger and ankle, respectively, were on par with those previously reported in Caucasians among twenty-two healthy non-supplementing strontium individuals by our group, an increase began to be seen after 24 hrs of 0.62 ± 0.14 and 0.45 ± 0.12 for the finger and ankle, respectively. By 120 h, the increase was statistically significant at 0.68 ± 0.07 and 0.93 ± 0.05, respectively. Further increases occurred within an interval of 90-180 days, with the most recent, after 800 days, at the finger and ankle being 7 and 15 times higher than the initial baseline reading. The intriguing results show bone strontium incorporation and retention follow a pattern, suggesting strontium levels, at least in the ankle, do not plateau within two to three years and will continue to increase over time, as an individual takes strontium supplements. The ability of this IVXRF system to monitor and measure bone strontium levels over time provides a useful diagnostic tool to help gain insight into strontium bone kinetics.

The effects of intravenous zoledronic acid in Chinese women with postmenopausal osteoporosis

The aim of this study was to assess the efficacy and safety of a once-yearly zoledronic acid treatment for Chinese women with postmenopausal osteoporosis in Taiwan and Hong Kong. This post hoc subpopulation analysis, from the Health Outcome and Reduced Incidence with Zoledronic Acid One Yearly Pivotal Fracture Trial, enrolled 323 Chinese women with osteoporosis who were randomly given either annual infusions of zoledronic acid or placebo for 3 consecutive years. The incidence of fractures and changes in bone mineral density (BMD) were measured; adverse events (AEs) and tolerability were recorded and assessed. The results of this study at 36 months demonstrate that there was a significantly reduced risk of morphometric vertebral fracture and clinical vertebral fracture in subjects treated with zoledronic acid (P < 0.05). In addition, there were significant increases of BMD by 4.9%, 4.3%, and 7.0% in the total hip, femoral neck, and trochanter, respectively, in the zoledronic acid group compared with the placebo group (P < 0.001 for all comparisons). The incidences of AEs were comparable between the two groups. Thus, once-yearly zoledronic acid treatment showed bone protection effects by reducing the risk of vertebral fracture and increasing BMD in Chinese women with postmenopausal osteoporosis.

Spotlight on strontium ranelate: in postmenopausal osteoporosis

This is a review of the pharmacology of strontium ranelate (Protelos, Protos, Protaxos, Bivalos, Osseor), and its efficacy and tolerability in the treatment of patients with postmenopausal osteoporosis. Strontium ranelate is a divalent strontium salt of ranelic acid that is capable of increasing bone formation and reducing bone resorption, thereby uncoupling and rebalancing bone turnover in favour of bone formation. The drug is effective in reducing the risk of fractures, including both vertebral and nonvertebral fractures, in patients with postmenopausal osteoporosis, according to data from two large, double-blind, placebo-controlled, multicentre trials of 5 years' duration, and reduced the risk of hip fracture in high-risk patients in a post hoc analysis of one trial. Moreover, data from patients who continued to receive the drug during the 3-year extension phase of these trials indicate that strontium ranelate continues to provide protection against new vertebral fractures and nonvertebral fractures for up to 8 years of therapy. It also improves bone mineral density at numerous sites and both increases markers of bone formation and decreases markers of bone resorption. Strontium ranelate is administered orally as a suspension and is generally well tolerated. The nature of adverse events was generally similar regardless of treatment duration in clinical trials, with the most commonly reported being nausea and diarrhoea over 5 years of treatment, and memory loss and diarrhoea during longer-term treatment. Although an increased risk of venous thromboembolism was associated with strontium ranelate relative to placebo over 5 years of treatment in a pooled analysis of clinical trials, postmarketing data have not confirmed this finding. Overall, the clinical data available suggest that strontium ranelate is an effective and generally well tolerated option for the first-line treatment of postmenopausal osteoporosis.

Strontium ranelate: a review of its use in the treatment of postmenopausal osteoporosis

This is a review of the pharmacology of strontium ranelate (Protelos, Protos, Protaxos, Bivalos, Osseor), and its efficacy and tolerability in the treatment of patients with postmenopausal osteoporosis. Strontium ranelate is a divalent strontium salt of ranelic acid that is capable of increasing bone formation and reducing bone resorption, thereby uncoupling and rebalancing bone turnover in favour of bone formation. The drug is effective in reducing the risk of fractures, including both vertebral and nonvertebral fractures, in patients with postmenopausal osteoporosis, according to data from two large, double-blind, placebo-controlled, multicentre trials of 5 years' duration, and reduced the risk of hip fracture in high-risk patients in a post hoc analysis of one trial. Moreover, data from patients who continued to receive the drug during the 3-year extension phases of these trials indicate that strontium ranelate continues to provide protection against new vertebral fractures and nonvertebral fractures for up to 8 years of therapy. It also improves bone mineral density at numerous sites and both increases markers of bone formation and decreases markers of bone resorption. Strontium ranelate is administered orally as a suspension and is generally well tolerated. The nature of adverse events was generally similar regardless of treatment duration in clinical trials, with the most commonly reported being nausea and diarrhoea over 5 years of treatment, and memory loss and diarrhoea during longer-term treatment. Although an increased risk of venous thromboembolism was associated with strontium ranelate relative to placebo over 5 years of treatment in a pooled analysis of clinical trials, postmarketing data have not confirmed this finding. Overall, the clinical data available suggest that strontium ranelate is an effective and generally well tolerated option for the first-line treatment of postmenopausal osteoporosis.