Safety considerations with bisphosphonates for the treatment of osteoporosis

Bazedoxifene: a new selective estrogen receptor modulator for postmenopausal osteoporosis

An ongoing need for safe and effective pharmacological therapies exists for postmenopausal osteoporosis, which imposes a significant burden on both women and the health-care system. Bazedoxifene is a novel selective estrogen receptor modulator with a unique tissue-selectivity profile. In phase 3 clinical trials of nearly 10,000 postmenopausal women, bazedoxifene was shown to significantly reduce the risk of new vertebral fracture versus placebo, with favourable effects on bone mineral density, bone turnover markers and the lipid profile. Moreover, in a subgroup of women at increased risk of fracture, bazedoxifene significantly decreased non-vertebral fracture risk versus both placebo and raloxifene. Bazedoxifene has been shown to be safe and well tolerated, with no evidence of endometrial or breast stimulation. These data suggest that bazedoxifene may offer significant clinical benefit for postmenopausal women with or at risk of developing osteoporosis, which may subsequently lessen the medical and economic burden of this disease.

Gastrointestinal tolerability and patterns of switching in patients treated for primary osteoporosis: the Swedish Adherence Register Analysis (SARA)

The objective of this study was to describe and analyze the gastrointestinal tolerability and medication switching in patients receiving treatment for primary osteoporosis in Sweden. The study was based on all patients starting therapy with alendronate, risedronate, strontium ranelate, and raloxifene in Sweden between 2005 and 2009. The primary outcome measure was start of treatment with a gastroprotective agent, and the secondary outcome was hospitalization for a gastrointestinal adverse event (GIAE). Switching was analyzed while patients were on treatment. The crude incidence of gastroprotective treatment during the first 6 months after initiation of osteoporosis therapy was 5.14%, 5.93%, 4.25%, and 2.86% for patients prescribed alendronate, risedronate, strontium ranelate, and raloxifene, respectively. Patients prescribed raloxifene had a significantly lower risk of filling a prescription for a gastroprotective agent compared with alendronate. There was no significant difference in the risk of hospitalization for GIAEs. Less than 3% switched therapy while on treatment. Patients prescribed risedronate, strontium ranelate, and raloxifene had a significantly higher risk of switching compared with patients taking alendronate. In conclusion, no significant difference in the incidence of GIAEs was found between patients prescribed alendronate, risedronate, and strontium ranelate. Individuals prescribed raloxifene had a significantly lower risk of GIAEs compared with patients prescribed alendronate. No significant difference was found in the frequency of hospitalization for GIAEs. Switching between osteoporosis medications and drug classes was uncommon. Prescribers should consider the real-world gastrointestinal safety of osteoporosis drugs when choosing between treatment options to potentially improve medication adherence and consequently effectiveness.

Safety of long-term bisphosphonate therapy for the management of osteoporosis

Drugs in the bisphosphonate class are the most commonly prescribed therapeutic agents for the treatment of osteoporosis. Prospective, randomized, placebo-controlled clinical trials have demonstrated efficacy in reducing fracture risk, with favourable safety profiles, in women with postmenopausal osteoporosis. However, long-term use in clinical practice has been associated with reports of undesirable events not previously recognized. These have included gastrointestinal intolerance, osteonecrosis of the jaw, atypical femur fractures, oesophageal cancer, atrial fibrillation and chronic musculoskeletal pain. Physicians must be alert to newly recognized safety concerns, understand the level of evidence supporting them and be able to effectively communicate the balance of expected benefit and potential risk to patients. Usually, post-marketing adverse events are first presented as case reports or observational studies with variable levels of supporting evidence for plausibility, pathophysiology and causality. Widespread coverage in the news media, which can be alarming to patients and their physicians, may not present a balanced view of the proven benefits, the uncertain risks of therapy and the relative magnitude of these events. There may be confusion about the risks associated with bisphosphonate use for the treatment of osteoporosis versus treatment of other conditions, such as cancer, which typically involves a very different patient population and different doses or frequency of drug administration. Often reports of possible adverse events do not provide information on the number of patients exposed to the drug in proportion to the reported adverse event, or do not describe the incidence of the adverse event in a comparator population not exposed to the drug. Gastrointestinal intolerance with oral bisphosphonates, and hypocalcaemia, acute phase reactions and renal toxicity with intravenous bisphosphonates are characterized by biological plausibility and demonstration of causality. Safety concerns with uncertain biological plausibility and unproven causality include osteonecrosis of the jaw, atypical femur fractures, oesophageal cancer and ocular inflammation. Suspected concerns that are unlikely to be causally related include atrial fibrillation and hepatotoxicity. When making the decision to use a bisphosphonate for the treatment of osteoporosis, the balance between benefit and potential risks according to clinical circumstances of each patient should be considered.

Alendronate and raloxifene use related to cardiovascular diseases: differentiation by different dosing regimens of alendronate

BACKGROUND

Bisphosphonates are the class of medication used most widely to treat osteoporosis. Since an article reported that patients who used zoledronic acid, a bisphosphonate, had a higher proportion of atrial fibrillation (AF) in 2007, the issue of bisphosphonates and AF has become a growing concern. Due to the widespread use of bisphosphonates, it is necessary to explore the relationship between bisphosphonates and AF and other cardiovascular diseases.

OBJECTIVE

We aimed to investigate the risk of AF, stroke, or acute myocardial infarction (AMI) associated with the use of the bisphosphonates alendronate and raloxifene in patients with osteoporosis. We also focused our analysis on the impact of different dosing regimens of alendronate.

METHODS

The National Health Insurance Research Database was used to conduct an 8-year, population-based, retrospective cohort study. The study population comprised women who first took alendronate or raloxifene between 2002 and 2006 and who had a history of osteoporosis and vertebral or spinal fracture. Follow-up was conducted for every patient until the first diagnosis of AF, stroke, or AMI or until the end of the 1-year follow-up period. The Cox proportional hazards model was used to evaluate the association between the risk of cardiovascular disease and the prescription of alendronate or raloxifene.

RESULTS

We identified 9609 women who had been prescribed either alendronate (n = 6949) or raloxifene (n = 2660). The patients treated with alendronate were at a lower risk of AF, stroke, or AMI compared with the raloxifene group (AF: hazard ratio [HR] = 0.60 [95% CI, 0.42-0.85]; stroke: HR = 0.47 [95% CI, 0.39-0.57]; AMI: HR = 0.51 [95% CI, 0.36-0.72]). However, when analyzing the groups by different alendronate dosing regimens, those patients who received alendronate 10 mg had a significantly higher risk of AF and stroke compared with patients who received raloxifene (AF: HR = 1.66 [95% CI, 1.12-2.46]; stroke: HR = 1.56 [95% CI, 1.23-1.98]). The alendronate 70-mg group demonstrated a lower risk of cardiovascular disease, be it AF, stroke, or AMI (AF: HR = 0.28 [95% CI, 0.18-0.43]; stroke: HR = 0.23 [95% CI, 0.18-0.30]; AMI: HR = 0.28 [95% CI, 0.18-0.41]). When we assigned alendronate 10 mg as the reference group, the alendronate 70 mg group had a lower risk of 3 cardiovascular diseases (AF: HR = 0.17 [95% CI, 0.10-0.27]; stroke: HR = 0.16 [95% CI, 0.12-0.22]; AMI: HR = 0.21 [95% CI, 0.13-0.35]).

CONCLUSIONS

Alendronate 10 mg was associated with a higher risk of cardiovascular disease than alendronate 70 mg. Further studies are required to investigate this relationship.

Adverse reactions and drug-drug interactions in the management of women with postmenopausal osteoporosis

The pharmacological management of disease should involve consideration of the balance between the beneficial effects of treatment on outcome and the probability of adverse effects. The aim of this review is to explore the risk of adverse drug reactions and drug-drug interactions with treatments for postmenopausal osteoporosis. We reviewed evidence for adverse reactions from regulatory documents, randomized controlled trials, pharmacovigilance surveys, and case series. Bisphosphonates are associated with gastrointestinal effects, musculoskeletal pain, and acute-phase reactions, as well as, very rarely, atrial fibrillation, atypical fracture, delayed fracture healing, osteonecrosis of the jaw, hypersensitivity reactions, and renal impairment. Cutaneous effects and osteonecrosis of the jaw are of concern for denosumab (both very rare), though there are no pharmacovigilance data for this agent yet. The selective estrogen receptor modulators are associated with hot flushes, leg cramps, and, very rarely, venous thromboembolism and stroke. Strontium ranelate has been linked to hypersensitivity reactions and venous thromboembolism (both very rare) and teriparatide with headache, nausea, dizziness, and limb pain. The solidity of the evidence base depends on the frequency of the reaction, and causality is not always easy to establish for the very rare adverse reactions. Drug-drug interactions are rare. Osteoporosis treatments are generally safe and well tolerated, though they are associated with a few very rare serious adverse reactions. While these are a cause for concern, the risk should be weighed against the benefits of treatment itself, i.e., the prevention of osteoporotic fracture.

The Rapidly Evolving Research on Vitamin D Among HIV-Infected Populations

With ongoing improvement in antiretroviral therapy, mortality among HIV-infected persons has dramatically decreased. For HIV-infected persons who remain engaged in care on suppressive therapy, life expectancy approaches that of the general population. Additionally, we have seen increases in comorbidities traditionally associated with aging: diabetes, hypertension, dyslipidemia, ischemic heart disease, and osteoporosis. Vitamin D deficiency has also been identified as a highly prevalent entity among HIV-infected populations. The association of vitamin D deficiency with several of these comorbidities and its impact on immune function provide the impetus for well-designed studies to evaluate the impact of vitamin D supplementation on HIV disease and antiretroviral therapy. This review summarizes the role of vitamin D in several disease states that are prevalent among HIV populations, with a specific focus on bone health and the interactions with antiretroviral medications.

Fluvastatin does not prevent the acute-phase response to intravenous zoledronic acid in post-menopausal women

The acute-phase response (APR) to aminobisphosphonates is triggered by activation of γδ T cells, resulting in pro-inflammatory cytokine release. Statins prevent aminobisphosphonate-induced γδ T cell activation in vitro, raising the possibility that statins might prevent the APR in vivo. The objective of this study was to determine whether fluvastatin prevents the APR to zoledronic acid in post-menopausal women. A double-blind, randomised, placebo-controlled study was conducted in 60 healthy, post-menopausal, female volunteers (mean age 60.6 ± 4.0). Volunteers received 5 mg zoledronic acid by intravenous infusion, and either three times 40 mg fluvastatin (0 hr, 24 hr and 48 hr), 40 mg fluvastatin (0 hr) plus placebo (24 hr and 48 hr), or placebo (0 hr, 24 hr and 48 hr), orally. Post-infusion symptoms were assessed by questionnaire. Changes in γδ T cell levels, pro-inflammatory cytokines (TNFα, IFNγ, IL-6) and C-reactive protein (CRP) were measured in peripheral blood at various time-points post-infusion. Zoledronic acid administration triggered increased serum levels of TNFα, IFNγ, IL-6 and CRP in ≥70% of study volunteers, whilst characteristic APR symptoms were observed in >50% of participants. Zoledronic acid also induced a transient fall in circulating Vγ9Vδ2 T cell levels at 48 hr, consistent with Vγ9Vδ2 T cell activation. Concurrent fluvastatin administration did not prevent zoledronic acid-induced cytokine release, alter circulating Vγ9Vδ2 T cell levels, nor diminish the frequency or severity of APR symptoms. In conclusion, intravenous zoledronic acid induced pro-inflammatory cytokine release and APR symptoms in the majority of study participants, which was not prevented by co-administration of fluvastatin.

Denosumab and bisphosphonates: different mechanisms of action and effects

To treat systemic bone loss as in osteoporosis and/or focal osteolysis as in rheumatoid arthritis or periodontal disease, most approaches target the osteoclasts, the cells that resorb bone. Bisphosphonates are currently the most widely used antiresorptive therapies. They act by binding the mineral component of bone and interfere with the action of osteoclasts. The nitrogen-containing bisphosphonates, such as alendronate, act as inhibitors of farnesyl-pyrophosphate synthase, which leads to inhibition of the prenylation of many intracellular signaling proteins. The discovery of RANKL and the essential role of RANK signaling in osteoclast differentiation, activity and survival have led to the development of denosumab, a fully human monoclonal antibody. Denosumab acts by binding to and inhibiting RANKL, leading to the loss of osteoclasts from bone surfaces. In phase 3 clinical studies, denosumab was shown to significantly reduce vertebral, nonvertebral and hip fractures compared with placebo and increase areal BMD compared with alendronate. In this review, we suggest that the key pharmacological differences between denosumab and the bisphosphonates reside in the distribution of the drugs within bone and their effects on precursors and mature osteoclasts. This may explain differences in the degree and rapidity of reduction of bone resorption, their potential differential effects on trabecular and cortical bone, and the reversibility of their actions.

Use of oral bisphosphonates by older adults with fractures and impaired renal function

BACKGROUND

The manufacturers of oral bisphosphonates (alendronate, risedronate) recommend avoiding use of these drugs in patients with renal impairment. However, many patients who have osteoporosis or who are at risk of fracture are elderly and may have renal impairment. This situation poses a quandary for clinicians in deciding how best to manage osteoporosis in this high-risk population.

OBJECTIVE

To synthesize published evidence regarding the use and safety of oral bisphosphonates for patients with impaired renal function.

METHODS

The following databases were searched up to October 2010: PubMed, MEDLINE, Embase, the Cochrane Library, and International Pharmaceutical Abstracts. The following key words and terms were used for the searches: bisphosphonates, alendronate, risedronate, Fosamax, Actonel, "renal failure", "renal insufficiency", "chronic kidney disease", and "end-stage renal disease". The manufacturers of Fosamax and Actonel were asked to provide information about use of their products in patients with renal impairment, including unpublished pharmacokinetic studies or reports of adverse drug events.

RESULTS

The search yielded 2 post hoc analyses of safety data, 1 case-control study, 1 case series, 4 retrospective chart analyses, and 2 prospective studies. According to these publications, numerous patients with decreased renal function have received bisphosphonates and have experienced improvement in bone mineral density and/or reduction in risk of fractures, with no increase in adverse effects. Increased renal damage occurred in some individuals with underlying renal disorders, as described in case reports.

CONCLUSIONS

Although the literature is limited, there is evidence that alendronate and risedronate are well tolerated and effective when used by individuals with renal impairment. Further research is required to confirm the benefits and risks of using these medications in patients with renal impairment.

Evaluation of a novel osteoporotic drug delivery system in vitro: alendronate-loaded calcium phosphate cement

As a new drug delivery system, calcium phosphate cement was fabricated with different concentrations of alendronate (2, 5, 10 wt%), which is widely used to treat diseases related to bone loss. This study investigated the properties of the novel composite alendronate-loaded calcium phosphate cement in vitro, and found that the structure and chemical properties of the composites were not different from the calcium phosphate cement. However, the calcium phosphate cement set time was significantly faster compared with other groups (P<.01), and the strength of the calcium phosphate cement was significantly greater than the other groups (P<.01). The alendronate release rate from the composite increased with increase in drug concentration in the cement, and release was sustained over 21 days. The composite showed good biocompatibility in terms of the proliferation of rat mesenchymal stem cells. The alendronate-loaded calcium phosphate cement displayed satisfactory properties in vitro, which may be of benefit locally for osteoporotic bone in vivo.

Long-term treatment with bisphosphonates and their safety in postmenopausal osteoporosis

Bisphosphonates are the leading drugs for the treatment of osteoporosis. In randomized controlled trials (RCTs), alendronate, risedronate, and zoledronate have shown to reduce the risk of vertebral, nonvertebral, and hip fractures, whereas RCTs with ibandronate show antifracture efficacy at vertebral sites. Bisphosphonates are generally well tolerated and safe. Nevertheless, adverse events have been noted, and it is important to consider the strength of the evidence for causal relationships. Effects on the gastrointestinal tract and kidney function are well recognized, as are transient acute-phase reactions. Atrial fibrillation was first identified as a potential adverse event in a zoledronate trial, but subsequent trials and analyses failed to substantiate an association with bisphosphonates. Case reports have suggested a relationship between oral bisphosphonates and esophageal cancer, but this has not been demonstrated in epidemiologic studies. A possible association between bisphosphonate use and osteonecrosis of the jaw (ONJ) has also been suggested. However, the risk of ONJ in patients with osteoporosis appears to be very low, with no evidence from prospective RCTs of a causal association. There are reports of occasional occurrence of subtrochanteric or diaphyseal fractures in osteoporotic patients, but an association with bisphosphonate therapy is not substantiated by epidemiologic studies or prospective RCTs.

Efficacy and safety of bazedoxifene, a novel selective estrogen receptor modulator for the prevention and treatment of postmenopausal osteoporosis

OBJECTIVE

Osteoporosis affects millions of individuals, particularly postmenopausal women, and imposes a severe burden on patients and the healthcare system. Several therapeutic options are commercially available for the prevention and treatment of osteoporosis, including bisphosphonates, hormone therapy, and the selective estrogen receptor modulator (SERM), raloxifene. Because each of these agents has its own individual risk-benefit profile, their use should be tailored to specific patient populations. While many agents are approved for osteoporosis, new therapies are needed that maximize efficacy outcomes and minimize safety concerns. Several new SERMs are being evaluated in an effort to achieve an ideal tissue selectivity profile, with beneficial effects on bone without negative effects on the endometrium and breast. Bazedoxifene is a novel SERM that was recently approved in the European Union and is undergoing regulatory review in the United States for the prevention and treatment of postmenopausal osteoporosis. This article reviews the clinical efficacy and safety data for bazedoxifene in postmenopausal women with or at risk for osteoporosis.

METHODS

The PubMed database and relevant congress abstract databases were searched to identify all pertinent literature on bazedoxifene for the prevention and/or treatment of postmenopausal osteoporosis.

RESULTS

In phase 3 clinical studies, bazedoxifene has demonstrated significant reduction in the risk of new vertebral fracture versus placebo and positive effects on bone mineral density and bone turnover. Moreover, in a subgroup analysis of women at high risk for fracture, bazedoxifene significantly reduced the risk of nonvertebral fracture versus both placebo and raloxifene. Bazedoxifene was generally safe and well-tolerated in women with and at risk for osteoporosis, with no evidence of endometrial or breast stimulation. Data inclusion for this review article was limited by what was available in the public domain.

CONCLUSION

The available clinical data suggest that bazedoxifene may offer a favorable risk-benefit profile for the prevention and treatment of postmenopausal osteoporosis.

Osteoporosis and venous thromboembolism: a retrospective cohort study in the UK General Practice Research Database

In a retrospective cohort study using the General Practice Research Database (GPRD), there was a greater association of venous thromboembolism (VTE) in osteoporotic than in non-osteoporotic female patients. No greater association was shown in treated patients with strontium ranelate or alendronate compared to untreated osteoporotic female patients.

INTRODUCTION

We explored the risk of VTE in usual practice in osteoporotic and non-osteoporotic women with and without anti-osteoporotic treatment.

METHODS

A retrospective study was conducted using the GPRD in the UK. The cohorts consisted of untreated osteoporotic women (N = 11,546), osteoporotic women treated with alendronate (N = 20,084), or strontium ranelate (N = 2,408), and a sample of non-osteoporotic women (N = 115,009). Cohorts were compared using a Cox proportional hazards regression model.

RESULTS

There was a significantly increased relative risk for VTE in untreated osteoporotic women versus non-osteoporotic women (annual incidence 5.6 and 3.2 per 1,000 patient-years, respectively; relative risk 1.75 [95% confidence interval (CI), 1.09-1.84]). Results were confirmed using adjusted models. The annual incidences of VTE in osteoporotic patients treated with strontium ranelate and alendronate were 7.0 and 7.2 per 1,000 patient-years, respectively, with no significant difference between untreated and treated patients whatever the treatment. Adjusted hazard ratios for treated versus untreated osteoporotic women were 1.09 (95% CI, 0.60-2.01) for strontium ranelate and 0.92 (95% CI, 0.63-1.33) for alendronate.

CONCLUSION

This study shows a greater association of VTE in osteoporotic compared to non-osteoporotic patients, but does not show any greater association in treated patients with strontium ranelate or alendronate compared to untreated osteoporotic patients.

Ibandronate and nonvertebral fracture efficacy: results of a recent pooled analysis

PRACTICE PEARL

The nonvertebral efficacy of ibandronate is demonstrated by a pooled analysis of all relevant clinical trials. ORIGINAL ARTICLE: Cranney A, Wells GA, Yetisir E, et al. Ibandronate for the prevention of nonvertebral fractures: a pooled analysis of individual patient data. Osteoporos Int. 2009;20(2):291-297.

Serum 25-hydroxyvitamin D levels modulate the acute-phase response associated with the first nitrogen-containing bisphosphonate infusion

The acute-phase response (APR) is the most frequent side effect after the first dose of intravenous nitrogen-containing bisphosphonates (N-BPs). It has been demonstrated in vitro that N-BPs stimulate gammadelta T-cell proliferation and production of cytokines and that vitamin D is able to modulate them. Therefore, we have studied the relationship between bone metabolism parameters, particularly for 25-hydroxyvitamin D [25(OH)D], and APR in patients treated with 5 mg zoledronic acid intravenously. Ninety N-BP-naive osteoporotic women (63.7 +/- 10.6 years of age) were stratified for the occurrence of APR (APR(+)) or not (APR(-)) and quantified by body temperature and C-reactive protein (CRP). The APR(+) women had significantly lower 25(OH)D levels than the APR(-) women. Levels of 25(OH)D were normal (>30 ng/mL) in 31% of APR(+) women and in 76% of APR(-) women. The odds ratio (OR) to have APR in 25(OH)D-depleted women was 5.8 [95% confidence interval (CI) 5.30-6.29; p < .0002] unadjusted and 2.38 (95% CI 1.85-2.81; p < .028) after multiple adjustments (for age, body mass index, CRP, calcium, parathyroid hormone, and C-telopeptide of type I collagen). Levels of 25(OH)D were negatively correlated with postdose body temperature (r = -0.64, p < .0001) and CRP (r = -0.79, p < .001). An exponential increase in fever and CRP has been found with 25(OH)D levels lower than 30 ng/mL and body temperature less than 37 degrees C, whereas normal CRP was associated with 25(OH)D levels above 40 ng/mL. The association between post-N-BPs APR and 25(OH)D suggests an interesting interplay among N-BPs, 25(OH)D, and the immune system, but a causal role of 25(OH)D in APR has to be proven by a randomized, controlled trial. However, if confirmed, it should have some practical implications in preventing APR.

Current and emerging pharmacologic therapies for the management of postmenopausal osteoporosis

Postmenopausal osteoporosis is an asymptomatic skeletal disease that is often underdiagnosed and undertreated. Osteoporotic fractures are associated with substantial morbidity and mortality and impaired quality of life-socially, emotionally, and financially. Considering the growing burden of osteoporotic fractures worldwide, there remains an ongoing need for progress in the diagnosis of osteoporosis, identification of individuals at high fracture risk, and treatment to prevent fractures. Adequate intake of calcium and vitamin D is recommended as baseline therapy for osteoporosis prevention and treatment. Available pharmacological agents for the management of postmenopausal osteoporosis may not be appropriate for all women. Oral bisphosphonates are generally considered first-line therapy for patients with osteoporosis, but their use may be limited by gastrointestinal side effects. Other agents include hormone therapy, the selective estrogen receptor modulator (SERM) raloxifene, salmon calcitonin, teriparatide (human recombinant parathyroid hormone), and strontium ranelate (in some countries). Factors that may contribute to poor compliance and persistence with current osteoporosis therapies include drug intolerance, complexity of dosing regimens, and poor understanding of the relative benefit and risk with treatment. Emerging therapies for postmenopausal osteoporosis include novel SERMs (bazedoxifene, lasofoxifene, ospemifene, arzoxifene) and denosumab. Because SERMs can display mixed functional estrogen receptor agonist or antagonist activity depending on the target tissue, they may confer beneficial effects on bone with limited stimulation of other tissues (e.g., breast, endometrium). Clinical investigation of these promising new agents is ongoing to evaluate efficacy and safety, with the goal of developing effective strategies to maximize long-term tolerance, compliance, and persistence with therapy.

Ibandronate: a review of its vertebral and nonvertebral antifracture efficacy

After the Ibandronate Osteoporosis Vertebral Fracture Trial in North America and Europe (BONE) study had demonstrated the strong vertebral and nonvertebral antifracture efficacy of daily and intermittent oral ibandronate, the Monthly Oral Ibandronate In Ladies (MOBILE) study gave evidence for an increased efficacy on the bone mineral density (BMD) of higher intermittent oral ibandronate doses (150 mg monthly) compared with 2.5 mg daily. The BONE study also observed nonvertebral antifracture efficacy in patients with a high risk for fractures (mean femoral neck T score of -3.0 or less). A recently published meta-analysis assessing the nonvertebral antifracture efficacy corresponding to the annual cumulative exposure (ACE) of ibandronate demonstrated a significantly better antifracture efficacy of higher compared with lower doses of ibandronate. The Dosing Intravenous Administration (DIVA) study demonstrated evidence for the high efficacy and good tolerability of intravenous ibandronate delivered by quarterly injections. This review summarizes the efficacy and tolerability data of ibandronate concerning monthly oral treatment as well as quarterly injection therapy.

Differences in persistence among different weekly oral bisphosphonate medications

SUMMARY

We evaluated the differences in persistence with weekly oral bisphosphonate therapy according to the initial drug. Persistence to weekly oral preparations remains suboptimal, particularly in patients who receive generic alendronate. Alternative solutions are needed to improve the real life effectiveness of osteoporosis therapies.

INTRODUCTION

Poor persistence is widespread with oral osteoporosis (OP) therapy. The objective of this study was to evaluate the persistence among OP patients started on weekly oral bisphosphonates (BP).

METHODS

Patients newly initiated on branded risedronate, branded alendronate, or generic alendronate once weekly were selected from the Régie de l'Assurance Maladie du Québec databases. The cohort included patients with and without a previous OP fracture. The probability and the risk factors for early discontinuation were estimated using Cox regression models.

RESULTS

The study cohort included 32,804 patients. After 1 year, a significant difference in persistence on oral BP therapy was found. The patients started on branded risedronate were 11% more likely to stop OP therapy than patients started on branded alendronate. Risk of discontinuation doubled in patients initiated with generic alendronate compared to patients started on branded alendronate. Male gender was associated with a 25% increase risk of early discontinuation. No statistical association was found between previous OP fracture and early discontinuation.

CONCLUSION

This study provides further evidence of poor persistence to newly initiated oral weekly BP therapies, particularly for the patients started on generic alendronate.

Efficacy and safety of risedronate 150 mg once a month in the treatment of postmenopausal osteoporosis

Fragility fractures that occur as a result of osteoporosis are frequently associated with chronic pain and decreased quality of life as well as significant morbidity and mortality. Fracture reduction, however, is often less than optimal due to poor compliance with medications. Studies have demonstrated that risedronate, a heterocyclic nitrogen containing bisphosphonate can reduce vertebral, nonvertebral, and hip fracture incidence in postmenopausal women, in men, and in subsets of older patients at great risk of falls and fragility. The mechanism, efficacy, dosing options, and tolerability of risedronate are reviewed.

Drug-induced esophagitis

Drug-induced esophagitis is being recognized increasingly in the past few years. Since 1970 more than 650 cases have been reported worldwide caused by 30 or more medications. We have reviewed these cases with a view to classifying this disease based on underlying pathological mechanism. Drug-induced esophageal injury tends to occur at the anatomical site of narrowing, with the middle third behind the left atrium predominating (75.6%). The disease is broadly classified into two groups. The first group being transient and self-limiting as exemplified by the tetracycline group induced injury (65.8%). The second is the persistent esophagitis group, often with stricture, with two distinct entities: (i) patients on nonsteroidal anti-inflammatory agents whose injury is aggravated by gastroesophageal reflux (21.8%) (reflux aggravated); and (ii) patients with potasium chloride and quinidine sulphate induced injury (12.4%) (persistent drug injury). Severe esophageal injury has been reported in some women taking biphosphonates as treatment for postmenopausal osteoporosis. Endoscopic findings in such patients with esophageal injury generally suggested a chemical esophagitis, with erosions or ulcerations and exudative inflammation accompanied by thickening of the esophageal wall. Most cases of medication-induced esophageal injury heal without intervention within a few days. Thus, the most important aspect of therapy is to make the correct diagnosis and then to avoid reinjury with the drug. When possible, potentially caustic oral medications should be discontinued.

Zoledronic acid and risedronate in the prevention and treatment of glucocorticoid-induced osteoporosis (HORIZON): a multicentre, double-blind, double-dummy, randomised controlled trial

BACKGROUND

Persistent use of glucocorticoid drugs is associated with bone loss and increased fracture risk. Concurrent oral bisphosphonates increase bone mineral density and reduce frequency of vertebral fractures, but are associated with poor compliance and adherence. We aimed to assess whether one intravenous infusion of zoledronic acid was non-inferior to daily oral risedronate for prevention and treatment of glucocorticoid-induced osteoporosis.

METHODS

This 1-year randomised, double-blind, double-dummy, non-inferiority study of 54 centres in 12 European countries, Australia, Hong Kong, Israel, and the USA, tested the effectiveness of 5 mg intravenous infusion of zoledronic acid versus 5 mg oral risedronate for prevention and treatment of glucocorticoid-induced osteoporosis. 833 patients were randomised 1:1 to receive zoledronic acid (n=416) or risedronate (n=417). Patients were stratified by sex, and allocated to prevention or treatment subgroups dependent on duration of glucocorticoid use immediately preceding the study. The treatment subgroup consisted of those treated for more than 3 months (272 patients on zoledronic acid and 273 on risedronate), and the prevention subgroup of those treated for less than 3 months (144 patients on each drug). 62 patients did not complete the study because of adverse events, withdrawal of consent, loss to follow-up, death, misrandomisation, or protocol deviation. The primary endpoint was percentage change from baseline in lumbar spine bone mineral density. Drug efficacy was assessed on a modified intention-to-treat basis and safety was assessed on an intention-to-treat basis. This trial is registered with ClinicalTrials.gov, number NCT00100620.

FINDINGS

Zoledronic acid was non-inferior and superior to risedronate for increase of lumbar spine bone mineral density in both the treatment (least-squares mean 4.06% [SE 0.28] vs 2.71% [SE 0.28], mean difference 1.36% [95% CI 0.67-2.05], p=0.0001) and prevention (2.60% [0.45] vs 0.64% [0.46], 1.96% [1.04-2.88], p<0.0001) subgroups at 12 months. Adverse events were more frequent in patients given zoledronic acid than in those on risedronate, largely as a result of transient symptoms during the first 3 days after infusion. Serious adverse events were worsening rheumatoid arthritis for the treatment subgroup and pyrexia for the prevention subgroup.

INTERPRETATION

A single 5 mg intravenous infusion of zoledronic acid is non-inferior, possibly more effective, and more acceptable to patients than is 5 mg of oral risedronate daily for prevention and treatment of bone loss that is associated with glucocorticoid use.

Optimizing dosing frequencies for bisphosphonates in the management of postmenopausal osteoporosis: patient considerations

Postmenopausal osteoporosis is common and underrecognized among elderly women. Osteoporotic fractures cause disability and disfigurement and threaten patients' mobility, independence, and survival. Care for incident fractures in this age group must go beyond orthopedic repair, to assessment and treatment of the underlying bone fragility. Fracture risk can be reduced by vitamin D and calcium supplementation along with antiresorptive drug treatment. First-line osteoporosis pharmacotherapy employs nitrogen-containing bisphosphonates. The inconvenience of daily oral treatment has motivated development of weekly, monthly, and intermittent oral regimens, as well as quarterly and yearly intravenous (i.v.) regimens. Ibandronate is the first bisphosphonate to have shown direct anti-fracture efficacy with a non-daily regimen; it was approved for once-monthly oral dosing in 2005 and for quarterly i.v. dosing in 2006. Intermittent oral risedronate and yearly i.v. zoledronic acid were approved in 2007. Newly available regimens with extended dosing intervals reduce the inconvenience of bisphosphonate therapy and provide patients with a range of options from which to select a maximally sustainable course of treatment. This review discusses the development, efficacy, safety, and tolerability of extended-interval bisphosphonate regimens and examines their potential to improve patient acceptance and long-term success of osteoporosis treatment.

Ibandronate: a review of its use in the management of postmenopausal osteoporosis

Ibandronate (ibandronic acid; Bonviva, Boniva), a nitrogen-containing bisphosphonate available in once-monthly oral and quarterly intravenous formulations for intermittent administration, has been approved for the treatment of osteoporosis in postmenopausal women in the EU, the US and many other countries worldwide. The once-monthly oral formulation has also been approved for the prevention of postmenopausal osteoporosis in the US. Ibandronate is an effective and generally well tolerated bisphosphonate that offers an alternative to other bisphosphonates as a first-line treatment for postmenopausal osteoporosis. It occupies a similar position with respect to the prevention of osteoporosis in postmenopausal women at risk for the disease. The once-monthly oral and quarterly intravenous dosage regimens have the potential to improve treatment adherence and persistence, and hence clinical outcomes, compared with more frequently administered oral bisphosphonates. Intravenous ibandronate may be particularly useful for postmenopausal osteoporotic women who are noncompliant with, or are unable to tolerate or receive, oral bisphosphonates. Thus, intermittent ibandronate extends the range of pharmacological therapies for the treatment and prevention of postmenopausal osteoporosis.

Conjugation of salmon calcitonin to a combed-shaped end functionalized poly(poly(ethylene glycol) methyl ether methacrylate) yields a bioactive stable conjugate

Salmon calcitonin (sCT) was conjugated via its N-terminal cysteine to a comb-shaped end-functionalized poly(poly(ethylene glycol) methyl ether methacrylate) (PolyPEG, 6.5 kDa), and to linear PEG (5 kDa). Conjugate molecular weight and purity was assessed by SEC-HPLC and MALDI-TOF MS. Bioactivity of conjugates was measured by cyclic AMP assay in T47D cells. Calcium and calcitonin levels were measured in rats following intravenous injections. Stability of conjugates was tested against serine proteases, intestinal and liver homogenates and serum. Cytotoxicity of conjugates was assessed by lactate dehydrogenase (LDH) assay and by haemolytic assay of rat red blood cells. Results showed that the two conjugates were of high purity with molecular weights similar to predictions. Both conjugates retained more than 85% bioactivity in vitro and had nanomolar EC(50) values similar to sCT. While both sCT-PolyPEG(6.5 K) and sCT-PEG(5 K) were resistant to metabolism by serine proteases, homogenates and serum, PolyPEG (6.5 K) was more so. Although both conjugates reduced serum calcium to levels similar to those achieved with sCT, PolyPEG(6.5 K) extended the T(1/2) and AUC of serum sCT over values achieved with sCT-PEG and sCT itself. None of PolyPEG, PEG or methacrylic acid displayed significant cytotoxicity. PolyPEG may therefore have potential to improve pharmacokinetic profiles of injected peptides.

Randomized, active-controlled study of once-weekly alendronate 280 mg high dose oral buffered solution for treatment of Paget's disease

Daily oral tablet bisphosphonate therapy for Paget's disease of bone may cause serious upper gastrointestinal adverse events. A once-weekly alendronate 280 mg oral buffered solution was compared with an alendronate 40 mg/day tablet. While both were similarly effective, the tablet appeared to be better tolerated in this study.

INTRODUCTION

Although daily doses of oral bisphosphonates are a generally safe and effective treatment for Paget's disease of bone (PDB), some patients may experience upper gastrointestinal adverse events (UGI AEs) or find the dosing requirements inconvenient and become noncompliant. A once-weekly (OW) oral dose of bisphosphonate in buffered solution (OBS) may be as effective, better tolerated, and more convenient.

METHODS

Sixty-three patients were randomized to either alendronate (ALN) 280 mg OW OBS (n = 42) or an ALN 40 mg/day tablet (n = 21) during a 6-month, randomized, double-blind, active-controlled trial. The primary endpoint was the mean percent decrease in total serum alkaline phosphatase (total ALP) from baseline at 6 months.

RESULTS

There were no significant differences in total ALP between groups during the 6-month period. There was a higher incidence of clinical AEs in the ALN 280 mg OW OBS (79%) vs. the ALN 40 mg/day tablet group (67%), including drug related AEs (48% and 10%, respectively), which led to study discontinuation (19.0% and 10%, respectively).

CONCLUSIONS

Although ALN 280 mg OW OBS was similarly effective as ALN 40 mg/day in reducing total ALP in patients with PDB, the ALN 40 mg/day tablet appears to be better tolerated than ALN 280 mg OW OBS.

Consensus guidelines for oral dosing of primarily renally cleared medications in older adults

OBJECTIVES

To establish consensus oral dosing guidelines for primarily renally cleared medications prescribed for older adults.

DESIGN

Literature search followed by a two-round modified Delphi survey.

SETTING

A nationally representative survey of experts in geriatric clinical pharmacy.

PARTICIPANTS

Eleven geriatric clinical pharmacists.

MEASUREMENTS

After a comprehensive literature search and review by an investigative group of six physicians (2 general internal medicine, 2 nephrology, 2 geriatrics), 43 dosing recommendations for 30 medications at various levels of renal function were created. The expert panel rated its agreement with each of these 43 dosing recommendations using a 5-point Likert scale (1=strongly disagree to 5=strongly agree). Recommendation-specific means and 95% confidence intervals were estimated. Consensus was defined as a lower 95% confidence limit of greater than 4.0 for the recommendation-specific mean score.

RESULTS

The response rate was 81.8% (9/11) for the first round. All respondents who completed the first round also completed the second round. The expert panel reached consensus on 26 recommendations involving 18 (60%) medications. For 10 medications (chlorpropamide, colchicine, cotrimoxazole, glyburide, meperidine, nitrofurantoin, probenecid, propoxyphene, spironolactone, and triamterene), the consensus recommendation was not to use the medication in older adults below a specified level of renal function (e.g., creatinine clearance <30 mL/min). For the remaining eight medications (acyclovir, amantadine, ciprofloxacin, gabapentin, memantine, ranitidine, rimantadine, and valacyclovir), specific recommendations for dose reduction or interval extension were made.

CONCLUSION

An expert panel of geriatric clinical pharmacists was able to reach consensus agreement on a number of oral medications that are primarily renally cleared.

[Bisphosphonate-induced collapsing focal segmental glomerulosclerosis; two clinical cases and literature review]

Collapsing focal segmental glomerulosclerosis is well described in its idiopathic form, mostly seen in young African American patients, and in association with HIV virus. Its clinical presentation typically includes proteinuria and renal failure rapidly progressing to end stage renal disease. However, a new form has recently been described related to treatment with high doses of intravenous bisphosphonates, especially pamidronate. We report two cases of collapsing focal segmental glomerulosclerosis in patients treated with intravenous pamidronate. In opposition to previous reports, interruption of pamidronate administration did not improve renal function. The latter should be evaluated before initiating treatment with bisphosphonates and regularly monitored. For patients with chronic kidney disease, introduction of bisphosphonates should be reconsidered given the risk of rapid progression to end stage renal disease and the lack of evidence for reduction of fracture risk in this population.

Bisphosphonates in the management of postmenopausal osteoporosis--optimizing efficacy in clinical practice

Nitrogen-containing bisphosphonates are potent inhibitors of osteoclastic bone resorption. With their individually proven efficacy to significantly reduce the incidence of vertebral and/or non-vertebral fractures and with their overall beneficial safety profile, alendronate, ibandronate, risedronate, and zoledronate are considered today a treatment of first choice in postmenopausal osteoporosis. However, treatment effects in an individual patient and cost-effectiveness in public health perspective are vitally dependent on the long-term patient adherence as well as on compliance and persistence. As compliance and persistence with daily oral bisphosphonates are shown to be suboptimal in many patients, leading to an increased fracture incidence in non-compliant patients, there is a need to improve overall adherence for bisphosphonate treatment in order to achieve maximum treatment effects. One option is to extend dosing intervals to weekly (alendronate, risedronate) or monthly (ibandronate) oral regimens. Less frequent oral regimens are generally preferred by majority of patients. Another alternative is intravenous, instead of oral application (ibandronate, zoledronate). Treatment acceptance could be further improved by IV bisphosphonates with their benefit of only quarterly, or even once-yearly, application. Treatment decisions should be based on anti-fracture efficacy data first. In addition, to ensure best possible patient adherence and maximum treatment benefits, physicians should consider individual patient conditions affecting compliance and persistence as well as patient preferences.

Bisphosphonates and bone fractures in long-term kidney transplant recipients

BACKGROUND

There is little information on the role of bisphosphonates and bone mineral density (BMD) measurements for the follow-up and management of bone loss and fractures in long-term kidney transplant recipients.

METHODS

To address this question, we retrospectively studied 554 patients who had two BMD measurements after the first year posttransplant and compared outcomes in patients treated, or not with bisphosphonates between the two BMD assessments. Kaplan-Meier survival and stepwise Cox regression analyses were performed to examine fracture-free survival rates and the risk-factors associated with fractures.

RESULTS

The average time (+/-SE) between transplant and the first BMD was 1.2+/-0.05 years. The time interval between the two BMD measurements was 2.5+/-0.05 years. There were 239 and 315 patients in the no-bisphosphonate and bisphosphonate groups, respectively. Treatment was associated with significant preservation of bone loss at the femoral neck (HR 1.56, 95% CI 1.21-2.06, P=0.0007). However, there was no association between bone loss at the femoral neck and fractures regardless of bisphosphonate therapy. Stepwise Cox regression analyses showed that type-1 diabetes, baseline femoral neck T-score, interleukin-2 receptor blockade, and proteinuria (HR 2.02, 0.69, 0.4, 1.23 respectively, P<0.01), but not bisphosphonates, were associated with the risk of fracture.

CONCLUSIONS

Bisphosphonates may prevent bone loss in long-term kidney transplant recipients. However, these data suggest a limited role for the initiation of therapy after the first posttransplant year to prevent fractures.

Quarterly intravenous ibandronate for postmenopausal osteoporosis

Osteoporosis is under-recognized and undertreated among postmenopausal women. Nitrogen-containing bisphosphonates are its first-line pharmacotherapy. Oral bisphosphonate treatment requires stringent dosing guidelines to minimize gastrointestinal irritation and enhance absorption. This paper reviews the efficacy, safety and tolerability of quarterly intravenous ibandronate 3 mg injection, approved in 2006 in the USA and Europe. Quarterly intravenous ibandronate injection has shown superior efficacy to daily oral ibandronate for bone mineral density increase and fracture prevention. No drug-related serious atrial fibrillation events have been reported with intravenous ibandronate. The regimen has a favorable renal safety profile. Quarterly intravenous ibandronate is administered as a simple 15-30-s intravenous injection in a physician's office and provides a beneficial option for patients who are unable to tolerate oral administration.

Cost effectiveness of screen-and-treat strategies for low bone mineral density: how do we screen, who do we screen and who do we treat?

Bone densitometry is currently widely recommended for, and considered central to, identifying post-menopausal women and older men at high risk of fracture and establishing an indication for pharmacological fracture-prevention therapy. The purpose of this article is to comprehensively review cost-effectiveness modelling studies published to date of bone mass measurement technologies (primarily dual energy x-ray absorptiometry [DXA]) designed to identify those individuals at sufficiently high risk of fracture to warrant pharmacological fracture-prevention therapy.Based on older paradigms of the pharmacological treatment of those with a bone density value below a specific threshold, bone densitometry appears to be cost effective for post-menopausal women aged > or =65 years, regardless of the presence or absence of other clinical risk factors. For younger post-menopausal women, bone densitometry is likely to be cost effective only for those with specific clinical risk factors, such as prior fracture or low bodyweight. For older men, bone densitometry may be cost effective for those who have had a prior fracture and/or are aged > or =80 years, but the subset of men for whom bone densitometry is likely to be cost effective may vary from country to country depending on societal willingness to pay for health benefits, fracture rates in the population and the costs of bone densitometry and drug treatment. The cost effectiveness of other technologies such as heel ultrasound, peripheral DXA and quantitative CT remains uncertain.However, in the context of the new WHO paradigm of directing treatment based on absolute fracture risk rather than bone density, a new generation of cost-effectiveness modelling studies will be required to define the most cost-effective way bone densitometry can be used to identify those who are likely to benefit sufficiently from pharmacological fracture-prevention therapies.