Category Archives: Minerals

Vitamin K2 (MK-4) + D + Calcium Reduces Lifetime Probability of Fracture by 25%

Abstract

Vitamin K supplementation for the primary prevention of osteoporotic fractures: is it cost-effective and is future research warranted?

Lifetime supplementation with vitamin K, vitamin D(3), and calcium is likely to reduce fractures and increase survival in postmenopausal women. It would be a cost-effective intervention at commonly used thresholds, but high uncertainty around the cost-effectiveness estimates persists. Further research on the effect of vitamin K on fractures is warranted.
Vitamin K might have a role in the primary prevention of fractures, but uncertainties about its effectiveness and cost-effectiveness persist.
We developed a state-transition probabilistic microsimulation model to quantify the cost-effectiveness of various interventions to prevent fractures in 50-year-old postmenopausal women without osteoporosis. We compared no supplementation, vitamin D(3) (800 IU/day) with calcium (1,200 mg/day), and vitamin K(2) (45 mg/day) with vitamin D(3) and calcium (at the same doses). An additional analysis explored replacing vitamin K(2) with vitamin K(1) (5 mg/day).
Adding vitamin K(2) to vitamin D(3) with calcium reduced the lifetime probability of at least one fracture by 25%, increased discounted survival by 0.7 quality-adjusted life-years (QALYs) (95% credible interval (CrI) 0.2; 1.3) and discounted costs by $8,956, yielding an incremental cost-effectiveness ratio (ICER) of $12,268/QALY. At a $50,000/QALY threshold, the probability of cost-effectiveness was 95% and the population expected value of perfect information (EVPI) was $28.9 billion. Adding vitamin K(1) to vitamin D and calcium reduced the lifetime probability of at least one fracture by 20%, increased discounted survival by 0.4 QALYs (95% CrI -1.9; 1.4) and discounted costs by $4,014, yielding an ICER of $9,557/QALY. At a $50,000/QALY threshold, the probability of cost-effectiveness was 80% while the EVPI was $414.9 billion. The efficacy of vitamin K was the most important parameter in sensitivity analyses.
Lifetime supplementation with vitamin K, vitamin D(3), and calcium is likely to reduce fractures and increase survival in postmenopausal women. Given high uncertainty around the cost-effectiveness estimates, further research on the efficacy of vitamin K on fractures is warranted.

Gajic-Veljanoski O, Bayoumi AM, Tomlinson G, Khan K…
Osteoporos Int Nov 2012
PMID: 22398856

Bisphosphonates Showed the Smallest Increase In Fracture Rate Over 10 Years

Abstract

Ten-year fracture risk in the assessment of osteoporosis management efficacy in postmenopausal women: a pilot study.

The aim of the reported longitudinal, retrospective pilot study was to establish changes in 10-year fracture risk in postmenopausal women with respect to applied fracture management.
A group of 191 postmenopausal women with a mean age of 68.76± 6.72 years was divided into subgroups. The subgroups were made up of untreated patients (n = 41), patients treated with vitamin D plus calcium (n = 46), and patients treated with bisphosphonates, vitamin D and calcium (n = 104). Repeated densitometric measurements and clinical data were taken into consideration (both baseline and follow-up). Ten-year fracture risk was established, using FRAX(TM) and Garvan nomograms. The mean follow-up period was 2.01±1.87 years.
Generally, the mean fracture probability increased in the studied women over the observation period. Patients on bisphosphonate therapy demonstrated the smallest increase in fracture probability. The probability rate for either any fractures or hip fractures decreased when the T-score increased. A diminished number of falls non-significantly decreased the probability for hip fractures and any fractures.
Ten-year fracture risk increased irrespective of applied management, while a decreased risk was observed only in women with improved bone status.

Pluskiewicz W, Drozdzowska B, Adamczyk P
Climacteric Feb 2013
PMID: 22335356

European Medicines Agency Recommends Restricting the use of Strontium Ranelate

In January 2014, the European Medicines Agency’s Pharmacovigilance Risk Assessment Committee (PRAC) recommended that Protelos/Osseor (Strontium Ranelate) should no longer be used to treat osteoporosis. Then, in February 2014,  it concluded its review of Protelos/Osseor and recommended further restricting the use of the medicine to patients who cannot be treated with other medicines approved for osteoporosis.

The following is from their press release:

In addition these patients should continue to be evaluated regularly by their doctor and treatment should be stopped if patients develop heart or circulatory problems, such as uncontrolled high blood pressure or angina. As recommended in a previous review, patients who have a history of certain heart or circulatory problems, such as stroke and heart attack, must not use the medicine.

These final recommendations from the Agency’s Committee for Medicinal Products for Human Use (CHMP) come after initial advice from the Pharmacovigilance Risk Assessment Committee (PRAC) to suspend the medicine due to its cardiovascular risk.

‘The CHMP agreed with the PRAC’s overall assessment of the risks of Protelos/Osseor. Both committees worked in close collaboration and the PRAC’s recommendation was instrumental for us to fully assess the benefit-risk profile of the medicine’, said Tomas Salmonson, chair of the CHMP. ‘However, the CHMP considered that, for patients who have no alternative treatment, regular screening and monitoring to exclude cardiovascular disease will sufficiently reduce the risk identified by the PRAC so that these patients can continue to have access to the medicine.’

In arriving at its conclusions, the CHMP noted that study data showed a beneficial effect in preventing fractures, including in patients at high risk of fracture. In addition, available data do not show evidence of an increased cardiovascular risk with Protelos/Osseor in patients who did not have a history of heart or circulatory problems.

The CHMP considered that the cardiovascular risk in patients taking Protelos/Osseor can be managed by restricting its use to patients with no history of heart and circulatory problems and limiting its use to those who cannot take other medicines approved for the treatment of osteoporosis. In addition, patients treated with Protelos/Osseor should be screened and monitored regularly, every 6 to 12 months.

Additional risk minimisation measures include providing educational material to prescribers to ensure that only the appropriate patients are treated with the medicine. Importantly, the company is required to conduct further research to demonstrate the effectiveness of the new measures. The Committee concluded that given the benefits seen in preventing fractures in patients at high risk, Protelos/Osseor should remain an option for patients with no history of cardiovascular disease who cannot take other medicines.

In deciding on how Protelos/Osseor should be used, the CHMP took into account thePRAC’s analysis of its benefits and risks as well as advice from osteoporosis experts that there is a group of patients who could benefit from the medicine.

‘The PRAC has worked closely with the CHMP throughout the procedure and while we acknowledge that the recommendations of the two committees differed, our understanding of the medicine’s benefit-risk profile is closely aligned and we share a common view of the importance of effective monitoring of cardiovascular risk’, said June Raine, chair of the PRAC. ‘The PRAC will continue to monitor the safety of Protelos /Osseor and the effectiveness of risk minimisation in long term use.’

The CHMP’s recommendation will now be sent to the European Commission, which will then issue a final decision.

 Information to patients

  • Protelos/Osseor will only be prescribed for preventing fractures in post-menopausal women and men with severe osteoporosis who have a high risk of fracture and cannot be treated with other medicines approved for osteoporosis.
  • Before starting treatment, your doctor will assess your risk of heart disease and high blood pressure and continue to check your risk at regular intervals during treatment.
  • You should not take Protelos/Osseor if you have or have had heart or circulatory problems such as stroke, heart attack, or obstruction of the blood flow in the arteries.
  • Your treatment with Protelos/Osseor will be stopped if you develop heart or circulatory problems during treatment.
  • If you have any questions, speak to your doctor or pharmacist.

Information to healthcare professionals

Healthcare professionals in the EU Member States will receive a letter informing them of the updated recommendations on the use of Protelos/Osseor. The letter will advise them of the following:

  • Protelos/Osseor should only be used to treat severe osteoporosis in postmenopausal women and men at high risk of fracture, for whom treatment with other medicinal products approved for the treatment of osteoporosis is not possible due to, for example, contraindications or intolerance;
  • Protelos/Osseor must not be used in patients with established, current or past history of ischaemic heart disease, peripheral arterial disease and/or cerebrovascular disease, or those with uncontrolled hypertension;
  • Doctors should continue to base their decision to prescribe Protelos/Osseor on an assessment of the individual patient’s risks. The patient’s risk of developing cardiovascular disease should be evaluated before starting treatment and on a regular basis thereafter, generally every 6 to 12 months;
  • Protelos/Osseor should be stopped if the patient develops ischaemic heart disease, peripheral arterial disease or cerebrovascular disease, or if hypertension is uncontrolled;
  • Doctors should review their patients currently on Protelos/Osseor as necessary.

This final EMA recommendation on the use of Protelos/Osseor was based on an analysis of pooled data from randomised studies in around 7,500 post-menopausal women with osteoporosis. The results showed an increased risk of myocardial infarction with Protelos/Osseor as compared with placebo (1.7% versus 1.1 %), with a relative risk of 1.6 (95% CI, 1.07 to 2.38), and an increased risk of venous thrombotic and embolic events — 1.9% versus 1.3 % with a relative risk of 1.5 (95% CI, 1.04 to 2.19).

Available data do not show evidence of an increased cardiovascular risk in patients without established, current or past history of ischaemic heart disease, peripheral arterial disease or cerebrovascular disease, or in those without uncontrolled hypertension.

Regarding the benefits, the efficacy data showed an effect in preventing fractures, including in patients at high risk of fracture.

More about the medicine

Protelos/Osseor (strontium ranelate) is authorised in the EU to treat severe osteoporosis (a disease that makes bones fragile) in women who have been through the menopause and who are at high risk of fracture (broken bones) to reduce the risk of fractures of the spine and the hip. It is also used to treat severe osteoporosis in men who are at high risk of fracture.

The current recommendations add to EMA recommendations made in April 2013 not to use Protelos/Osseor in patients with known circulatory problems.

More about the procedure

The review of Protelos/Osseor was initiated in May 2013 at the request of European Commission under Article 20 of Regulation (EC) No 726/2004.

The first stage of this review was conducted by the Pharmacovigilance Risk Assessment Committee (PRAC), the committee responsible for the evaluation of safety issues for human medicines, which made a set of recommendations. The PRAC’s recommendations were then sent to the Committee for Medicinal Products for Human Use (CHMP) responsible for all questions concerning medicines for human use, which adopted the Agency’s final opinion.

Further information on the PRAC recommendation and the background to this review can be found on Agency’s website. The CHMP opinion will now be forwarded to the European Commission, which will issue a final decision in due course.

Review: Exercise Only Beneficial with Calcium > 1000mg per Day

Abstract

Evidence for an interaction between calcium intake and physical activity on changes in bone mineral density.

Results of trials on the effects of physical activity on bone mineral density (BMD) are conflicting. The current hypothesis was that calcium intake modifies the bone response to physical activity. Published trials on physical activity and bone density were reviewed, and the results of 17 trials are summarized. Physical activity has beneficial effects on BMD at high calcium intakes, with no effect at mean calcium intakes less than a mean of 1000 mg/day. The modifying effect of calcium intake on BMD among exercise groups is more pronounced in the lumbar spine than in the radius. This analysis may explain conflicting results of trials on physical activity and calcium effects on bone. Controlled trials designed to test adequately this hypothesis are needed.

Specker BL
J. Bone Miner. Res. Oct 1996
PMID: 8889855

Calcium Threonate may Influence Bone Mineralization Through its Action on Vitamin C

Abstract

Pharmacokinetics and safety of calcium L-threonate in healthy volunteers after single and multiple oral administrations.

To evaluate the pharmacokinetics of L-threonate after single or multiple oral administrations and its safety profile in healthy Chinese volunteers. This was an open-label, single- and multiple-dose study. The subjects were assigned to receive a single dose, 675, 2025, or 4050 mg, of calcium L-threonate (n=12) or repeated doses of 2025 mg twice daily for 4 d (n=12). Serial plasma and urine samples were analyzed with HPLC-MS/MS. Pharmacokinetic parameters of L-threonate were calculated using non-compartmental analysis with WinNonlin software.
In the single dose group, C(max) reached at 2.0 h and the mean t(1/2) was approximately 2.5 h. Area under curve (AUC) and C(max) increased with dose escalation, but dose proportionality was not observed over the range of 675 to 4050 mg. AUC and C(max) in the fasted subjects were lower compared with those in the non-fasted subjects. Cumulative urinary excretion of L-threonate over 24 h represented 5.9% of the administered dose with a mean Cl/r of 0.8 L/h. In the multiple-dose study, no accumulation appeared upon repeated doses of 2025 mg twice daily for 4 d. There were no serious adverse events that occurred during this study.
Calcium L-threonate was well tolerated in healthy Chinese subjects, with no pattern of dose-related adverse events. Plasma exposure increased with dose escalation, but linear pharmacokinetics were not observed over the studied doses. L-threonate was absorbed rapidly, and its absorption was enhanced by food intake. No systemic accumulation appeared after repeated administrations.

Wang HY, Hu P, Jiang J
Acta Pharmacol. Sin. Dec 2011
PMID: 21986570 | Free Full Text

The introduction is the most interesting part of the article.

L-Threonic acid is an active metabolite of vitamin C5, 6, 7, 8. It has been reported that L-threonic acid exhibits significant stimulatory action on vitamin C uptake and prolongs the retention of vitamin C in human T-lymphoma cells9, 10. It is also well known that vitamin C is a marker for osteoblast formation and has been shown to stimulate procollagen and enhance collagen synthesis11, 12, 13, 14. Therefore, L-threonic acid may play a role in the mineralization process through its positive action on vitamin C. This hypothesis was confirmed in 1999 by Rowe DJ15. It was reported that in vitro treatment with ascorbate-containing vitamin C metabolites enhanced the formation of the mineralized nodules and collagenous proteins and that L-threonate was one of the metabolites that was found to influence the mineralization process15. Recently, a preclinical study was performed to investigate the effect of L-threonate on bone resorption of rabbit osteoclasts16. This study contained a total of six culture groups, including one control group and five groups treated with drugs (calcium L-threonate, sodium L-threonate, alendronate, 17β-estradiol and calcium gluconate). The levels of type I collagen C-telopeptide (CTx) and bone slice resorptive area were measured. This study found that L-threonate, especially calcium L-threonate, inhibited the bone resorption of osteoclasts in vitro; however, the reductive effects on the CTx level and resorptive area were not as significant as alendronate and 17β-estradiol at the same concentration.

Calcium L-threonate ((2R,3S)-2,3,4-trihydroxy butyric acid calcium) (Figure 1) is a novel drug developed for the treatment of osteoporosis and as a calcium supplement. Phase I clinical trials of calcium L-threonate, including tolerance, pharmacokinetics and calcium absorption evaluation, were performed in Peking Union Medical College Hospital. In this paper, the pharmacokinetics of L-threonate after single or multiple oral administrations and its safety profile in healthy Chinese volunteers are presented.

Strontium Increases Bone Density Measurement by Increased Attenuation of X-rays

Abstract

The correction of BMD measurements for bone strontium content.

Strontium ranelate (SR) is a new oral treatment for osteoporosis associated with large increases in bone mineral density (BMD) compared with alternative therapies such as bisphosphonates. Much of the BMD increase during SR treatment is a physical effect caused by the increased attenuation of X-rays due to the accumulation of strontium in bone tissue. The aim of this study was to assess the contribution made by bone strontium content (BSC) to the overall BMD increase by evaluating the percentage F of the BMD change explained by the physical presence of strontium in bone. A value of F less than 100% would provide evidence of the anabolic effect of SR as an additional factor contributing to the overall BMD increase. Studies of mixtures of strontium hydroxyapatite (SrHA) and calcium hydroxyapatite (CaHA) scanned on a variety of dual-energy X-ray absorptiometry (DXA) systems show that a 1% molar ratio of SrHA/(CaHA+SrHA) causes a 10% overestimation of BMD. The correction of spine BMD measurements for the physical effects of strontium depends on knowledge of 2 further factors: (1) bone biopsy measurements of iliac crest BSC and (2) the ratio R of BSC at the DXA site to BSC at the iliac crest measured in animal studies. We used clinical trial data and values of R(spine) measured in studies of monkeys and beagle dogs to determine values of F(spine) for 1, 2, and 3 yr treatment with SR. Based on the average value of R(spine) approximately 0.7 for male and female monkeys, we found values for F(spine) approximately 75-80% for 1, 2, and 3 yr of treatment. Using the value of R(spine) approximately 1.0 from the beagle study gave values of F(spine) approximately 100%. Although values of F(spine) as low as 40% are possible, we conclude that the most likely figure is 75% or greater. However, it is apparent that there are large uncertainties in the correction of BMD results for the effect of bone strontium and that the most important of these is the inference of BSC values at DXA scan sites from measurements of iliac crest bone biopsy specimens.

Blake GM, Fogelman I
J Clin Densitom
PMID: 17543560

Review: Strontium Increases Bone Formation and Reduces Resorption, but may Increase Risk of Venous Thromboembolism

Abstract

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.

Deeks ED, Dhillon S
Drugs Apr 2010
PMID: 20394457

Strontium Safe and Reduces Fracture Risk Over 10 Years in Postmenopausal Women

Abstract

Maintenance of antifracture efficacy over 10 years with strontium ranelate in postmenopausal osteoporosis.

In an open-label extension study, BMD increased continuously with strontium ranelate over 10 years in osteoporotic women (P < 0.01). Vertebral and nonvertebral fracture incidence was lower between 5 and 10 years than in a matched placebo group over 5 years (P < 0.05). Strontium ranelate’s antifracture efficacy appears to be maintained long term.
Strontium ranelate has proven efficacy against vertebral and nonvertebral fractures, including hip, over 5 years in postmenopausal osteoporosis. We explored long-term efficacy and safety of strontium ranelate over 10 years.
Postmenopausal osteoporotic women participating in the double-blind, placebo-controlled phase 3 studies SOTI and TROPOS to 5 years were invited to enter a 5-year open-label extension, during which they received strontium ranelate 2 g/day (n = 237, 10-year population). Bone mineral density (BMD) and fracture incidence were recorded, and FRAX® scores were calculated. The effect of strontium ranelate on fracture incidence was evaluated by comparison with a FRAX®-matched placebo group identified in the TROPOS placebo arm.
The patients in the 10-year population had baseline characteristics comparable to those of the total SOTI/TROPOS population. Over 10 years, lumbar BMD increased continuously and significantly (P < 0.01 versus previous year) with 34.5 ± 20.2% relative change from baseline to 10 years. The incidence of vertebral and nonvertebral fracture with strontium ranelate in the 10-year population in years 6 to 10 was comparable to the incidence between years 0 and 5, but was significantly lower than the incidence observed in the FRAX®-matched placebo group over 5 years (P < 0.05); relative risk reductions for vertebral and nonvertebral fractures were 35% and 38%, respectively. Strontium ranelate was safe and well tolerated over 10 years.
Long-term treatment with strontium ranelate is associated with sustained increases in BMD over 10 years, with a good safety profile. Our results also support the maintenance of antifracture efficacy over 10 years with strontium ranelate.

Reginster JY, Kaufman JM, Goemaere S, Devogelaer JP…
Osteoporos Int Mar 2012
PMID: 22124575 | Free Full Text

Strontium Prevents Inhibitory Effect of AGEs on Osteoblasts

Abstract

Strontium ranelate prevents the deleterious action of advanced glycation endproducts on osteoblastic cells via calcium channel activation.

Accumulation of advanced glycation endproducts (AGEs) in bone tissue occurs in ageing and in Diabetes mellitus, and is partly responsible for the increased risk of low-stress bone fractures observed in these conditions. In this study we evaluated whether the anti-osteoporotic agent strontium ranelate can prevent the deleterious effects of AGEs on bone cells, and possible mechanisms of action involved. Using mouse MC3T3E1 osteoblastic cells in culture we evaluated the effects of 0.1mM strontium ranelate and/or 100 μg/ml AGEs-modified bovine serum albumin (AGEs-BSA) on cell proliferation, osteogenic differentiation and pro-inflammatory cytokine production. We found that AGEs-BSA alone decreased osteoblastic proliferation and differentiation (P<0.01) while increasing IL-1β and TNFα production (P<0.01). On its own, strontium ranelate induced opposite effects: an increase in osteoblast proliferation and differentiation (P<0.01) and a decrease in cytokine secretion (P<0.01). Additionally, strontium ranelate prevented the inhibitory and pro-inflammatory actions of AGEs-BSA on osteoblastic cells (P<0.01). These effects of strontium ranelate were blocked by co-incubation with either the MAPK inhibitor PD98059, or the calcium channel blocker nifedipine. We also evaluated by Western blotting the activation status of ERK (a MAPK) and b-catenin. Activation of both signaling pathways was decreased by AGEs treatment, and this inhibitory effect was prevented if AGEs were co-incubated with strontium ranelate (P<0.01). On its own, strontium ranelate increased both pERK and activated b-catenin levels. In conclusion, this study demonstrates that strontium ranelate can prevent the deleterious in vitro actions of AGEs on osteoblastic cells in culture by mechanisms that involve calcium channel, MAPK and b-catenin activation.

Fernández JM, Molinuevo MS, Sedlinsky C, Schurman L…
Eur. J. Pharmacol. Apr 2013
PMID: 23499695