Treatment with once-weekly alendronate 70 mg compared with once-weekly risedronate 35 mg in women with postmenopausal osteoporosis: a randomized double-blind study

Long-term outcome of weekly bisphosphonates

Bisphosphonates currently are the preferred therapy for treating osteoporosis. Treatment with potent bisphosphonates such as alendronate or risedronate decreases biochemical markers of bone turnover and increases bone mineral density. These changes are associated with significant reductions in vertebral and nonvertebral fracture risk. Clinical trial data with up to 10 years of followup shows these agents are effective and well tolerated for long-term periods. Daily administration is effective and generally well tolerated. However, once weekly doses are more convenient, which may enhance long-term compliance and lead to more successful outcomes. The pharmacokinetics and mechanism of action predict the short-term and long-term skeletal effects and safety profile of once-weekly doses of bisphosphonates are similar to daily doses. These predictions are supported by authors of trials of up to 2 years who report once-weekly doses are therapeutically equivalent to daily doses in terms of BMD and biochemical markers of bone remodeling. Once-weekly bisphosphonate doses have safety and tolerability profiles as good as daily doses and are comparable with the placebo.

LEVEL OF EVIDENCE

Therapeutic study, Level V (expert opinion). See the Guidelines for Authors for a complete description of the levels of evidence.

A randomized, placebo-controlled, 6-month study of once-weekly alendronate oral solution for postmenopausal osteoporosis

OBJECTIVE

This study evaluated the overall safety and tolerability of once-weekly (OW) alendronate 70 mg oral solution (OS) versus OW placebo OS.

METHODS

Postmenopausal, osteoporotic women were enrolled at 51 centers in the United States in a 6-month double-blind, randomized trial. Patients were randomized (1:1) to OW alendronate 70 mg OS or placebo OS. The primary end point was the proportion of patients reporting any upper gastrointestinal (UGI) adverse event (AE) at 6 months. Secondary end points included mean percentage change in urinary N-telopeptide of type I human collagen (NTx) and serum bone-specific alkaline phosphatase (BSAP) at 6 months.

RESULTS

Initially, 454 women were enrolled; 392 (86.3%) completed the study. The mean (SD) age was 65.2 (10) years, and the mean (SD) time since menopause was 19.1 (12) years. The proportion of patients experiencing any UGI AE was significantly higher with alendronate OS (23.7%) compared with placebo solution (15.3%), with a treatment difference of 8.3% (95% CI, 0.8%-15.8%; P = 0.024). The proportion of patients experiencing any esophageal AE was 4.0% with alendronate and 3.0% with placebo (treatment difference, 1.0% [95% CI, -2.7% to 4.8%]). In addition, 4.5% of alendronate and 8.7% of placebo patients discontinued the study due to any clinical AE, and 3.3% of alendronate and 1.8% of placebo patients discontinued due to a UGI AE (difference, 1.5% [95% CI, -1.5% to 4.4%]). Alendronate OS produced significantly greater reductions in both NTx and BSAP than placebo (differences, -47.5% and -38.7%, respectively [both, P < 0.001]).

CONCLUSIONS

In this 6-month study, patients receiving OW alendronate 70 mg OS had a higher rate of UGI AEs than placebo patients. However, rates of serious UGI AEs, discontinuations due to UGI AEs, and esophageal AEs were similar between groups. UGI AEs in the study were generally mild to moderate in severity and did not result in treatment discontinuation. In addition, OW alendronate 70 mg OS significantly reduced biochemical markers of bone turnover.

Pharmacologic and nonpharmacologic management of osteoporosis

Fractures that occur as a result of osteoporosis are associated with significant morbidity, mortality, and cost. A treatment regimen consisting of both nonpharmacologic and pharmacologic interventions can be used to decrease the risk of fracture. Nonpharmacologic interventions include calcium and vitamin D supplementation, weight-bearing exercise, muscle strengthening, and fall prevention. Pharmacologic options include: the bisphosphonates, estrogen therapy, raloxifene, salmon calcitonin, and the anabolic agent teriparatide. Although bone mineral density is used clinically to diagnose osteoporosis, it is of limited value when evaluating pharmacologic treatment; the primary indicator of treatment efficacy is fracture risk reduction. The bisphosphonates are the preferred therapy for osteoporosis. Studies have demonstrated that in postmenopausal women, both risedronate and alendronate are associated with reductions in vertebral and nonvertebral fracture risk. The newest approved bisphosphonate, ibandronate, reduces vertebral fracture risk. Studies also support a reduction in fracture risk when alendronate and risedronate are used in men with osteoporosis and patients with corticosteroid-induced osteoporosis. When used appropriately, the bisphosphonates are well tolerated. Estrogen and raloxifene decrease fracture risk in postmenopausal women with osteoporosis but are associated with thromboembolic events. Use of estrogen therapy is also limited by concerns about the safety of this type of therapy. Although the anabolic agent teriparatide is associated with reductions in vertebral and nonvertebral fractures, its use has been limited by the necessity of subcutaneous administration and its cost relative to other agents. Regardless of which treatment regimen is selected, health care providers need to emphasize the importance of compliance and adherence to improve persistence with therapy, and subsequent fracture reduction efficacy.

Clinical significance of risedronate for osteoporosis in the initial treatment of male patients with Graves' disease

It has been well established that hyperthyroidism leads to diminished bone mineral density (BMD), and that a previous history of hyperthyroidism remains a risk factor for fractures. However, little is known about how to manage the reduction in BMD caused by hyperthyroidism. The purpose of this study was to evaluate the efficacy of risedronate for the treatment of osteoporosis/osteopenia in patients with Graves' disease (GD). Of 34 Japanese male patients with newly diagnosed GD, 27 with osteoporosis/osteopenia were included in this study. They were randomly divided into two groups by therapeutic regimen. Group A consisted of 14 patients treated with an antithyroid drug and risedronate. Group B consisted of 13 patients treated with the same antithyroid drug only. We used dual-energy X-ray absorptiometry to measure BMD at the lumber spine, femoral neck, and distal radius at baseline, and at 6 and 12 months after the trial. Bone-specific alkaline phosphatase and urinary N-terminal telopeptide of type I collagen normalized by creatinine were significantly more reduced in group A than in group B after both 6 and 12 months. The percentage increases in BMD at the lumbar spine and distal radius were significantly greater in group A than in group B. These beneficial effects of risedronate for patients with osteoporosis/osteopenia caused by GD may lead to a reduced risk of future fractures. We thus conclude that risedronate should be considered for the treatment of decreased bone mass associated with GD.

Long-Term Safety of Bisphosphonate Therapy for Osteoporosis

This article reviews the long-term safety profile of bisphosphonates for the treatment and prevention of osteoporosis in postmenopausal women. Bisphosphonates inhibit osteoclastic resorption and reduce the rate of bone turnover, thereby reducing fracture risk. Placebo-controlled trials of oral amino-bisphosphonates of up to 4 years' duration and continuous treatment for up to 10 years in extensions of these trials (without continuous placebo comparison groups) have reported that bone quality remains normal, and suggest that the early reductions in fracture risk may be sustained for as long as treatment continues. Studies in animals using high doses of bisphosphonates have also reported normal quality bone with increased strength. The adverse experience profile (including upper gastrointestinal tolerability) of the oral bisphosphonates alendronic acid and risedronic acid has been similar to placebo in randomised trials with thousands of participants, whereas the incidence of flu-like symptoms was increased with the high doses used in oral monthly and intravenous ibandronic acid. Thus, the existing data are reassuring for long-term continued daily (or its weekly equivalent) administration of alendronic acid and risedronic acid, with no evidence of an adverse effect on bone health. For other dosing regimens, additional data are needed to evaluate their long-term safety.

Alendronic Acid Produces Greater Effects than Risedronic Acid on Bone??Density and Turnover in Postmenopausal Women with Osteoporosis

BACKGROUND

The objective of the study was to evaluate the effects of alendronic acid once weekly relative to risedronic acid once weekly on bone mineral density (BMD), markers of bone turnover and tolerability in the treatment of osteoporosis in postmenopausal women.

METHODS

This was a randomised, double-masked, double-dummy multicentre international study (75 centres in 27 countries in Europe, the Americas and Asia-Pacific). A total of 1303 women were screened and 936 with low bone density (T-score < or = -2.0 at the spine, hip trochanter, total hip or femoral neck) were randomised; 91% (n = 854) completed the study. Patients were randomised to treatment with either active alendronic acid 70 mg weekly (Fosamax) and placebo identical to risedronic acid weekly or active risedronic acid 35 mg weekly (Actonel) and placebo identical to alendronic acid weekly for 12 months. The primary efficacy endpoint was the percentage change from baseline in hip trochanter BMD at 12 months. Secondary endpoints included the percentage change from baseline in lumbar spine, total hip and femoral neck BMD; biochemical markers of bone turnover (including serum bone-specific alkaline phosphatase [BSAP] and urinary type I collagen N-telopeptides [NTx]); and safety and tolerability as assessed by reporting of adverse experiences.

RESULTS

Alendronic acid produced greater increases in BMD than did risedronic acid at 12 months at all sites measured. Mean percentage increases from baseline in hip trochanter BMD at month 12 were 3.56% and 2.71% in the alendronic acid and risedronic acid groups, respectively (treatment difference [95% CI]: 0.83% [0.22, 1.45; p = 0.008]). Mean percentage increases from baseline were greater with alendronic acid than risedronic acid at the lumbar spine, total hip and femoral neck BMD at month 12 (p = 0.002, p < 0.001, p = 0.039, respectively). Increases in BMD with alendronic acid compared with risedronic acid were also significantly greater at 6 months at the trochanter and total hip. There was a greater reduction in bone turnover with alendronic acid compared with risedronic acid: NTx decreased 58% with alendronic acid compared with 47% with risedronic acid at 12 months (p < 0.001); and BSAP decreased 45% with alendronic acid compared with 34% with risedronic acid at 12 months (p < 0.001). Overall tolerability and upper gastrointestinal tolerability were similar for both agents.

CONCLUSIONS

Alendronic acid once weekly produced greater BMD increases at both hip and spine sites and greater reductions in bone turnover relative to risedronic acid once weekly. Both agents were well tolerated with no significant difference in upper gastrointestinal adverse experiences. Clinicians should consider these results when making treatment decisions for postmenopausal women with osteoporosis.

Channeling and adherence with alendronate and risedronate among chronic glucocorticoid users

INTRODUCTION

Despite the efficacy of bisphosphonates to reduce fractures in high risk populations, bisphosphonate adherence among chronic glucocorticoid users has received limited attention. Moreover, perceived differences in GI tolerability may lead physicians to preferentially prescribe particular bisphosphonates.

METHODS

Among chronic glucocorticoid users (>60 days of therapy) enrolled in managed care, we identified individuals initiating therapy with alendronate or risedronate during 2001-2004. Multivariable logistic regression and proportional hazards models were used to examine factors associated with channeling patients to risedronate (versus alendronate) and with discontinuation (>3-month gap without refill). The Medication Possession Ratio (MPR) was calculated as the filled days of medication divided by the interval of time between prescriptions.

RESULTS

Of 1,158 glucocorticoid users initiating bisphosphonate therapy, demographic characteristics of alendronate users (n=754) and risedronate users (n=404) were similar for age (mean 53 years) and gender (approximately 80% female). Past history of a GI symptom or event was associated with risedronate receipt (OR=2.24, 95% CI 1.15-4.35). After multivariable adjustment, rates of discontinuation (mean time to discontinuation approximately 18 months) and adherence (mean MPR=73%) were similar between users of the two bisphosphonates. Younger age, greater medical comorbidity, and lack of BMD testing were significantly associated with discontinuation.

CONCLUSIONS

Overall persistence rates were suboptimal for bisphosphonate use among chronic glucocorticoids users and did not differ significantly by drug. Newer strategies to promote long-term adherence are needed to improve osteoporosis therapeutic effectiveness.

Bone mineral density and lipid changes during 5 years of follow-up in a study of prevention of breast cancer with toremifene in healthy, high-risk pre- and post-menopausal women

A double-blind, randomised, placebo-controlled pilot study was initiated to evaluate the feasibility of chemoprevention with toremifene 60 mg/day in healthy women at high risk for breast cancer. Enrolment in the study was terminated earlier than planned because of slow patient accrual, although 13% of patients continued for 5 years. The revised efficacy outcomes were change in bone mineral density (BMD) from baseline at four skeletal sites, plus effects on serum lipids. In premenopausal women there was a trend for sustained increase in BMD during toremifene therapy after year 1 in lumbar spine. In postmenopausal women, toremifene had little or no effect on BMD trends. Levels of total and low-density lipoprotein (LDL) cholesterol were largely unchanged from baseline in premenopausal women treated with toremifene but were often slightly lower than in the placebo group during follow-up. Total and LDL cholesterol levels declined slightly from baseline in the postmenopausal women and were, at several points during the first 3 years, significantly lower than in the corresponding placebo group (p < 0.01). We conclude that: (a) assessment of toremifene 60 mg/day in chemoprevention will require further clinical trials; (b) toremifene 60 mg/day has no substantive negative effects on BMD in pre- or postmenopausal women and may exert a minor favourable influence (in particular, the effects of toremifene 60 mg/day on BMD in premenopausal women may make the drug an attractive alternative to tamoxifen 20 mg/day for that patient subset); (c) lipid effects of toremifene 60 mg/day are, at minimum, neutral and may be modestly favourable for reducing cardiovascular risk.

Who will benefit from antiresorptive treatment (bisphosphonates)?

Bisphosphonates are very effective treatments of postmenopausal osteoporosis. They suppress bone turnover, increase bone mineral density (BMD), and maintain or improve structural and material properties of bone, thereby decreasing the risk of fractures. All patients selected for treatment according to current international guidelines can benefit from bisphosphonate therapy independently of their prevalent rate of bone turnover. Long-term extensions (up to 10 years) of pivotal clinical trials with daily bisphosphonate administration showed sustained efficacy with no evidence of adverse effects on bone metabolism and skeletal fragility. Recent studies focus on the resolution of the effects of bisphosphonates on bone metabolism and fracture risk following cessation of long-term treatment. Such studies may help to formulate treatment recommendations according to the risk of the individual patient.

Management of Bone Health in Postmenopausal Women

Osteoporosis is a major public health problem. We now have an approach to case finding that involves the measurement of bone mineral density in people at high risk of fractures. The management of the individual includes the identification of risk factors, the choice of optimal therapy and the encouragement of long-term adherence with the planned treatment. The drugs that are available for the prevention of fractures are classed as anticatabolic or anabolic. The efficacy of these agents can be evaluated in the individual by monitoring changes in bone mineral density or bone turnover markers.

Biological properties and mechanism of action of ibandronate: application to the treatment of osteoporosis

Bisphosphonates, with their proven efficacy and safety, are the most commonly prescribed treatment for women with postmenopausal osteoporosis; however, optimal efficacy is often not achieved due to poor patient adherence to medication. Poor adherence leads to an increased risk of fracture, which itself results in morbidity, elevated healthcare costs and potentially, mortality. Although weekly rather than daily dosing of bisphosphonates has improved adherence, there remains a significant problem, and dosing less frequently than weekly has been suggested as a possible means for further improving adherence. Ibandronate is a new bisphosphonate that has a specific structure and set of characteristics that enable less frequent dosing than currently available bisphosphonates. This review provides details of the general structural features of all bisphosphonates and how these are understood to contribute to their functions in osteoporosis treatment. From this, the unique structure of ibandronate is described, along with how this translates into the high antiresorptive potency, favorable bone-binding, persistence in bone, and good tolerability that permits less frequent dosing. Finally, the clinical evidence for ibandronate is briefly presented, demonstrating the viability of less frequent dosing, with its potential benefits for patient convenience and adherence to therapy.

Review of Treatment Modalities for Postmenopausal Osteoporosis

This review summarizes and updates data presented at recent annual Southern Medical Association conferences on postmenopausal osteoporosis. As part of any osteoporosis treatment program, it is important to maintain adequate calcium and 25-hydroxyvitamin D levels either through diet or supplementation. Among the available pharmacologic therapies, the bisphosphonates alendronate and risedronate have demonstrated the most robust fracture risk reductions-approximately 40 to 50% reduction in vertebral fracture risk, 30 to 40% in nonvertebral fracture risk, and 40 to 60% in hip fracture risk. Ibandronate, a new bisphosphonate, has demonstrated efficacy in reducing vertebral fracture risk. Salmon calcitonin nasal spray and raloxifene demonstrated significant reductions in vertebral fracture risk in pivotal studies. Teriparatide significantly reduced vertebral and nonvertebral fracture risk. Drugs on the horizon include strontium ranelate, which has been shown to reduce vertebral and nonvertebral fracture risk, and zoledronic acid, an injectable bisphosphonate that increased bone density with once-yearly administration.

Bone density and markers of bone turnover in predicting fracture risk and how changes in these measures predict fracture risk reduction

Surrogate markers in clinical medicine provide a useful means to assess therapeutic response to pharmacologic therapy in a wide range of chronic disease states. In the area of osteoporosis, the surrogate markers of change in bone mineral density (BMD) and bone turnover markers (BTM) provide the clinician with a means of assessing the biologic response to osteoporosis-specific pharmacologic agents. Increases in BMD and/or reductions in BTM can independently be correlated to reductions in vertebral and nonvertebral fracture risk. In managing osteoporosis patients, the BTM change at an earlier point of time after initiation of therapy and a change in BTM can provide earlier feed-back to the patient and clinician regarding issues such as compliance and a bone biologic response. An increase in BMD at 12 or 24 months after initiation of therapy is also evidence of an improvement in bone strength though with antiresorptive agents no change in BMD may also be associated with risk reduction within clinical trial sets. In this regard, changes in BMD and BTM are complimentary in their application to patient management.

Pharmacokinetics/pharmacodynamics of bisphosphonates: use for optimisation of intermittent therapy for osteoporosis

Bisphosphonates suppress osteoclast-mediated bone resorption and are widely used in the management of osteoporosis. Daily oral administration of alendronic acid and risedronic acid have been shown to reduce the risk of vertebral and non-vertebral fractures. Once-weekly regimens with these bisphosphonates are pharmacologically equivalent to daily regimens. Regimens with treatment-free intervals longer than 1 week present an attractive therapeutic option as they may offer additional patient convenience and long-term adherence to treatment. However, until recently, such regimens, usually referred to as intermittent or cyclical, have not shown any convincing antifracture efficacy in clinical trials, probably because of the empirical manner in which the design of these regimens has been approached. Investigation of pharmacokinetics/pharmacodynamics of bisphosphonates may help in the design of effective intermittent dosage regimens. Bisphosphonates are poorly absorbed from the gastrointestinal tract and about 50% of the absorbed drug is taken up selectively by the skeleton, while the rest is excreted unaltered in urine. Bisphosphonates exert their action at the bone surface, where they are taken up by the osteoclasts during bone resorption. Therefore, when describing the pharmacokinetics of bisphosphonates in relation to the pharmacodynamics, the amount of bisphosphonate at the skeleton should be accounted for. Few of the reported clinical pharmacokinetic studies addressed this issue. This is partly due to the absence of study design elements to account for skeletal binding of the drugs. Pharmacokinetic studies have also been hampered by technical difficulties in determining the concentration of bisphosphonates in serum and urine. Moreover, most clinical pharmacokinetic (but also pharmacokinetic/pharmacodynamic) studies have primarily used noncompartmental analysis, leaving out the distinct advantages of modelling and simulation techniques. Clinically, the primary action of bisphosphonates can be assessed by the measurement of biochemical markers of bone resorption. Recent studies indicate that the pattern of these markers during bisphosphonate treatment may be predictive of antifracture efficacy; however, only limited data are available for the development of pharmacokinetic/pharmacodynamic models that are able to predict the response of these markers to different treatment regimens with bisphosphonates. Recently, pharmacokinetic/pharmacodynamic models for response to bisphosphonates have been described and, at present, some of them are being used in the design of bisphosphonate regimens with long drug-free intervals.

Osteoporosis therapy: an example of putting evidence-based medicine into clinical practice

A major aim of evidence-based medicine is to assist clinical decision-making by providing the most current and reliable medical information. Systematic reviews and meta-analyses are important tools in this process. Systematic reviews identify and compile relevant evidence, while meta-analyses summarize and quantify the results of such reviews. Results from meta-analyses are, at present, the main source of summary evidence for the efficacy of treatments for a specific condition. They are important tools for helping to choose among treatment options, although they cannot be used to directly compare the magnitude of the effect of various therapies. However, the methods used and the consequent clinical value of the results, may be poorly understood by clinicians, who may therefore not take full advantage of the evidence. Recently, a panel of experts in osteoporosis and evidence-based medicine applied rigorous, validated, scientific standards to produce a systematic review and meta-analysis of randomized controlled trials of anti-resorptive agents used to treat osteoporosis. They found that, although several agents reduced the risk of vertebral fracture, only two, alendronate and risedronate, demonstrated convincing evidence for both non-vertebral and vertebral fracture risk reductions. The clinical implication of these results is that there are important differences in anti-fracture efficacy among currently available agents. In the absence of evidence from head-to-head clinical trials and because of the systematic nature and methodological rigor of the analyses, these data provide important information for clinical decision-making.

How useful are measures of BMD and bone turnover?

Measurements of bone mineral density (BMD) and biochemical markers of bone turnover are useful in the diagnosis and management of osteoporosis, as well as in research relating to the pathogenesis and treatment of the disease. Recent challenges to the utility of these measures have resulted in some confusion among both researchers and clinicians. BMD accounts for the great majority of bone strength and is the current gold standard for the diagnosis of osteoporosis, as well as for prediction of fracture risk. Although bone turnover increases sharply after menopause, biochemical markers of bone turnover have limited usefulness in fracture risk prediction. Persistently elevated bone turnover throughout the menopause is associated with structural decrements, cannot be measured routinely and non-invasively. In research applications, both BMD and markers of bone turnover are used to identify candidate agents in preclinical and clinical studies. In addition, head-to-head comparisons of treatments utilize these measures, because fracture endpoint trials would need to be extraordinarily large and complex. Analyses that have suggested that change in BMD or bone turnover 'explains' little of change in fracture risk with treatment appear to be flawed. Although neither can perfectly predict fracture, they are our current best alternatives.

Discovery, clinical development, and therapeutic uses of bisphosphonates

OBJECTIVE

To review the literature concerning the history, development, and therapeutic uses of bisphosphonates.

DATA SOURCES

English-language articles were identified through a search of MEDLINE (through December 2004) using the key word bisphosphonate. Reference lists of pivotal studies, reviews, and full prescribing information for the approved agents were also examined.

STUDY SELECTION AND DATA EXTRACTION

Selected studies included those that discussed the discovery and initial applications of bisphosphonates, as well as their historical development, pharmacokinetic and pharmacodynamic properties, and current therapeutic uses.

DATA SYNTHESIS

Bisphosphonates structurally resemble pyrophosphates (naturally occurring polyphosphates) and have demonstrated similar physicochemical effects to pyrophosphates. In addition, bisphosphonates reduce bone turnover and resist hydrolysis when administered orally. The information gained from initial work with etidronate generated a considerable scientific effort to design new and more effective bisphosphonates. The PCP moiety in the general bisphosphonate structure is essential for binding to hydroxyapatite and allows for a number of chemical variations by changing the 2 lateral side chains (designated R(1) and R(2)). The R(1) side chain determines binding affinity to hydroxyapatite, and the R(2) side chain determines antiresorptive potency. Accordingly, each bisphosphonate has its own characteristic profile of activity.

CONCLUSIONS

The bisphosphonates reduce bone turnover, increase bone mass, and decrease fracture risk and therefore have a significant place in the management of skeletal disorders including osteoporosis, Paget's disease, bone metastases, osteogenesis imperfecta, and heterotopic ossification.

Rehabilitation of orthopedic and rheumatologic disorders. 1. Osteoporosis assessment, treatment, and rehabilitation

This self-directed learning module highlights a clinical vignette of a female patient with osteoporosis and addresses the clinical presentation, assessment, medical management, and rehabilitation approaches to a patient with an acute vertebral fracture. It is part of the study guide on osteoporosis in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This chapter emphasizes the differential diagnosis, clinical diagnostic considerations, current pharmacotherapy, invasive procedure options, and orthotic and exercise interventions for a patient with postmenopausal osteoporosis.

OVERALL ARTICLE OBJECTIVE

To summarize the clinical evaluation, medical management, and rehabilitation strategies in women with postmenopausal osteoporosis and acute vertebral fracture presentation.