Changes in biochemical markers and bone mass after withdrawal of ibandronate treatment: prediction of bone mass changes during treatment

Pre-treatment bone turnover does not influence the level of the response to alendronate in postmenopausal osteoporosis at the bone tissue level

PURPOSE

The main effect of anti-resorptive agents such as bisphosphonates is a reduction of bone resorption, with a consequent marked decrease of bone turnover. This post-hoc analysis investigated the changes of histomorphometric parameters of bone turnover after alendronate (ALN), according to the baseline turnover.

METHODS

Ninety postmenopausal women underwent a transiliac bone biopsy before and after 6 (n = 44) or 12 (n = 46) months of treatment with ALN (70 mg/week). The dynamic parameters reflecting the bone formation and bone turnover were mineralizing surface (MS/BS; %), bone formation rate (BFR/BS; μm3/μm2/d), and activation frequency (Ac.f; /yr). Biochemical markers sPINP and the sCTX were assessed before treatment and after 3, 6, and 12 months. Subjects were divided into quartiles based on the baseline values of BFR/BS.

RESULTS

At baseline, MS/BS and Ac.f were significantly different (p < 0.0001) among the BFR quartiles. sCTX and sP1NP were not significantly different among quartiles. After ALN treatment, MS/BS was not significantly different among quartiles but Ac.f remained significantly lower in the first quartile compared to the third and fourth ones (p < 0.03). The absolute value of the difference between pre- and post-treatment significantly correlated with the baseline BFR/BS but when expressed in percent of the baseline value, the magnitude of the diminutions of MS/BS, Ac.f, sCTX, and sP1NP was similar in the four baseline BFR quartiles.

CONCLUSION

The percentage response to ALN appeared independent of the baseline level of bone turnover. After treatment, the bone turnover tended to be similar in all BFR quartiles. This analysis investigated the influence of baseline turnover measured by bone histomorphometry on the effect of alendronate. When expressed in percent of pre-treatment values, the decreases of histomorphometric parameters and biochemical markers of bone turnover were independent of the baseline turnover.

Bisphosphonate alternative regimens for the prevention of osteoporotic fragility fractures: BLAST-OFF, a mixed-methods study

Background

Bisphosphonates are a class of medication commonly used to treat osteoporosis. Alendronate is recommended as the first-line treatment; however, long-term adherence (both treatment compliance and persistence) is poor. Alternative bisphosphonates are available, which can be given intravenously and have been shown to improve long-term adherence. However, the most clinically effective and cost-effective alternative bisphosphonate regimen remains unclear. What is the most cost-effective bisphosphonate in clinical trials may not be the most cost-effective or acceptable to patients in everyday clinical practice.

Objectives

1. Explore patient, clinician and stakeholder views, experiences and preferences of alendronate compared to alternative bisphosphonates. 2. Update and refine the 2016 systematic review and cost-effectiveness analysis of bisphosphonates, and estimate the value of further research into their benefits. 3. Undertake stakeholder/consensus engagement to identify important research questions and further rank research priorities.

Methods

The study was conducted in two stages, stages 1A and 1B in parallel, followed by stage 2: • Stage 1A - we elicited patient and healthcare experiences to understand their preferences of bisphosphonates for the treatment of osteoporosis. This was undertaken by performing a systematic review and framework synthesis of qualitative studies, followed by semistructured qualitative interviews with participants. • Stage 1B - we updated and expanded the existing Health Technology Assessment systematic review and clinical and cost-effectiveness model, incorporating a more comprehensive review of treatment efficacy, safety, side effects, compliance and long-term persistence. • Stage 2 - we identified and ranked further research questions that need to be answered about the effectiveness and acceptability of bisphosphonates.

Results

Patients and healthcare professionals identified a number of challenges in adhering to bisphosphonate medication, balancing the potential for long-term risk reduction against the work involved in adhering to oral alendronate. Intravenous zoledronate treatment was generally more acceptable, with such regimens perceived to be more straightforward to engage in, although a portion of patients taking alendronate were satisfied with their current treatment. Intravenous zoledronate was found to be the most effective, with higher adherence rates compared to the other bisphosphonates, for reducing the risk of fragility fracture. However, oral bisphosphonates are more cost-effective than intravenous zoledronate due to the high cost of zoledronate administration in hospital. The importance of including patients and healthcare professionals when setting research priorities is recognised. Important areas for research were related to patient factors influencing treatment selection and effectiveness, how to optimise long-term care and the cost-effectiveness of delivering zoledronate in an alternative, non-hospital setting.

Conclusions

Intravenous zoledronate treatment was generally more acceptable to patients and found to be the most effective bisphosphonate and with greater adherence; however, the cost-effectiveness relative to oral alendronate is limited by its higher zoledronate hospital administration costs.

Future work

Further research is needed to support people to make decisions influencing treatment selection, effectiveness and optimal long-term care, together with the clinical and cost-effectiveness of intravenous zoledronate administered in a non-hospital (community) setting.

Limitations

Lack of clarity and limitations in the many studies included in the systematic review may have under-interpreted some of the findings relating to effects of bisphosphonates.

Trial registration

This trial is registered as ISRCTN10491361.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR127550) and is published in full in Health Technology Assessment; Vol. 28, No. 21. See the NIHR Funding and Awards website for further award information.

UK clinical guideline for the prevention and treatment of osteoporosis

The National Osteoporosis Guideline Group (NOGG) has revised the UK guideline for the assessment and management of osteoporosis and the prevention of fragility fractures in postmenopausal women, and men age 50 years and older. Accredited by NICE, this guideline is relevant for all healthcare professionals involved in osteoporosis management.

INTRODUCTION

The UK National Osteoporosis Guideline Group (NOGG) first produced a guideline on the prevention and treatment of osteoporosis in 2008, with updates in 2013 and 2017. This paper presents a major update of the guideline, the scope of which is to review the assessment and management of osteoporosis and the prevention of fragility fractures in postmenopausal women, and men age 50 years and older.

METHODS

Where available, systematic reviews, meta-analyses and randomised controlled trials were used to provide the evidence base. Conclusions and recommendations were systematically graded according to the strength of the available evidence.

RESULTS

Review of the evidence and recommendations are provided for the diagnosis of osteoporosis, fracture-risk assessment and intervention thresholds, management of vertebral fractures, non-pharmacological and pharmacological treatments, including duration and monitoring of anti-resorptive therapy, glucocorticoid-induced osteoporosis, and models of care for fracture prevention. Recommendations are made for training; service leads and commissioners of healthcare; and for review criteria for audit and quality improvement.

CONCLUSION

The guideline, which has received accreditation from the National Institute of Health and Care Excellence (NICE), provides a comprehensive overview of the assessment and management of osteoporosis for all healthcare professionals involved in its management. This position paper has been endorsed by the International Osteoporosis Foundation and by the European Society for the Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases.

Bone Mineral Density Loss and Fracture Risk After Discontinuation of Anti-osteoporotic Drug Treatment: A Narrative Review

The number of patients on long-term anti-osteoporotic drug therapy is rising. Unfortunately, there are few data to guide decisions about duration of pharmacologic therapy for osteoporosis. Many practitioners discontinue therapy after a period of 5 years because of the risk of rare but severe side effects that may occur in long-term users. The objective of this narrative review was to describe the effects of discontinuation of anti-osteoporotic drugs and to investigate what is not yet known on this topic. For each anti-osteoporotic agent, PubMed was searched for evidence from randomized clinical trials in patients with osteoporosis on osteoporotic drugs lasting ≥ 3 years, followed by ≥ 1 year of follow-up after discontinuation of therapy and reported at least one item of the following: changes in bone mineral density, bone turnover markers and/or the risk of vertebral and/or nonvertebral fractures after discontinuation of therapy. The% change in bone mineral density (BMD) after 1 year of discontinuation of therapy is − 0.4% or less at the hip and femoral neck in both alendronate- and zoledronic acid-treated patients. In the other reported agents (risedronate, ibandronate, raloxifene, teriparatide, denosumab and romosozumab) this percentage of bone loss at the femoral neck and total hip was at least 1%, with the largest decrease in BMD after discontinuation of denosumab and romosozumab. In all studies reporting bone turnover markers, a substantial rapid rise in these markers was observed after discontinuation of therapy, with a large rebound increase to far above baseline levels in the denosumab-treated patients. There were few data on fracture risk after discontinuation of therapy; data showed that discontinuing alendronate, zoledronic acid and especially denosumab significantly increases the risk of vertebral fractures. In conclusion, osteoporosis should be considered more as a chronic condition. Therefore, in modern fracture risk management, continuous monitoring and treatment is required, as is the case with other chronic diseases, to sustain the benefits of therapy, especially in denosumab- and romosozumab-treated patients. The exception is alendronate and zoledronic acid, in these patients a discontinuation of drug therapy of 1 year or more might be acceptable.

Bisphosphonate drug holidays: Risk of fractures and mortality in a prospective cohort study

PURPOSE

This study examined osteoporotic fractures and mortality in patients pretreated with bisphosphonates (BPs) during BP holidays and ongoing BP use.

METHODS

Interview-based prospective observational study in a cohort of 1973 patients with BP treatment for at least 80% of the total time of the preceding 4 years. Patients were recruited from 146 primarily endocrinological, orthopedic and rheumatological practices and clinics across Germany between May 2013 and June 2015. Outcomes were analyzed by Cox proportional hazards regression in relation to treatment status at the time of the first interview (model 1) or using time-dependent treatment variables (model 2). Temporal changes in fracture risk during BP holidays were evaluated by comparisons among 3 incremental levels of simple moving averages of BP treatment during the preceding 12 months (BP-SMA levels 0%, >0% to <50%, and ≥50%).

RESULTS

For an observation period of up to 25 months, the adjusted hazard ratios (HRs) in model 1 for BP holidays compared to ongoing BP use were 0.87 (95% confidence interval [CI] 0.59-1.28) for major osteoporotic fractures (MOFs), 0.95 (95% CI 0.70-1.28) for any clinical osteoporotic fracture, 0.96 (95% CI 0.55-1.68) for clinical vertebral fractures, and 0.86 (95% CI 0.50-1.48) for mortality. The risk of MOFs was higher for the BP-SMA level 0%, corresponding to a time >12 months since the start of a BP holiday, than for the BP-SMA level >0% to <50%, corresponding mainly to a time >6 to ≤12 months since the start of a BP holiday (adjusted HR 2.28, 95% CI 1.07-4.86). We found an interaction between prevalent vertebral fractures (PVFs) and BP-SMA-related time to first MOF for BP-SMA as a continuous variable (p for interaction 0.046 in the adjusted model). The adjusted HR for MOFs for the BP-SMA level 0% compared to the BP-SMA level >0% to <50% was 3.53 (95% CI 1.19-10.51) with a PVF but was 1.44 (95% CI 0.49-4.22) without a PVF.

CONCLUSIONS

Fracture risk and mortality in patients with preceding BP treatment did not significantly differ between BP holidays and ongoing BP use for an observation period up to 25 months when outcomes were analyzed in relation to treatment at the time of the first interview. However, in the presence of a PVF, the risk of MOFs was higher for a BP-SMA level corresponding to a time >12 months since the start of a BP holiday than for a BP-SMA level corresponding mainly to a time >6 to ≤12 months since the start of a BP holiday. The presence of a PVF may increase the relative risk of MOFs associated with a longer BP holiday.

Practical guidance for the use of bisphosphonates in osteoporosis

Bisphosphonates are widely used in the treatment of osteoporosis in postmenopausal women and older men. In clinical trials they have been shown to reduce fractures in women with osteoporosis and there is increasing evidence that they are also effective in women with osteopenia, in whom the majority of fractures occur. In addition to their role as initial therapy in individuals at increased risk of fracture, bisphosphonates are used as sequential therapy after treatment with anabolic drugs. There are no head-to head studies to compare the anti-fracture efficacy of different bisphosphonates, but there is limited evidence that zoledronate treatment results in greater increases in BMD than risedronate or alendronate. This, together with the need for less frequent administration of zoledronate, supports its wider use in clinical practice, particularly if longer dosing intervals than those currently recommended are shown to be effective.

Denosumab, raloxifene, romosozumab and teriparatide to prevent osteoporotic fragility fractures: a systematic review and economic evaluation

BACKGROUND

Fragility fractures are fractures that result from mechanical forces that would not ordinarily result in fracture.

OBJECTIVES

The objectives were to evaluate the clinical effectiveness, safety and cost-effectiveness of non-bisphosphonates {denosumab [Prolia®; Amgen Inc., Thousand Oaks, CA, USA], raloxifene [Evista®; Daiichi Sankyo Company, Ltd, Tokyo, Japan], romosozumab [Evenity®; Union Chimique Belge (UCB) S.A. (Brussels, Belgium) and Amgen Inc.] and teriparatide [Forsteo®; Eli Lilly and Company, Indianapolis, IN, USA]}, compared with each other, bisphosphonates or no treatment, for the prevention of fragility fracture.

DATA SOURCES

For the clinical effectiveness review, nine electronic databases (including MEDLINE, EMBASE and the World Health Organization International Clinical Trials Registry Platform) were searched up to July 2018.

REVIEW METHODS

A systematic review and network meta-analysis of fracture and femoral neck bone mineral density were conducted. A review of published economic analyses was undertaken and a model previously used to evaluate bisphosphonates was adapted. Discrete event simulation was used to estimate lifetime costs and quality-adjusted life-years for a simulated cohort of patients with heterogeneous characteristics. This was done for each non-bisphosphonate treatment, a strategy of no treatment, and the five bisphosphonate treatments previously evaluated. The model was populated with effectiveness evidence from the systematic review and network meta-analysis. All other parameters were estimated from published sources. An NHS and Personal Social Services perspective was taken, and costs and benefits were discounted at 3.5% per annum. Fracture risk was estimated from patient characteristics using the QFracture® (QFracture-2012 open source revision 38, Clinrisk Ltd, Leeds, UK) and FRAX® (web version 3.9, University of Sheffield, Sheffield, UK) tools. The relationship between fracture risk and incremental net monetary benefit was estimated using non-parametric regression. A probabilistic sensitivity analysis and scenario analyses were used to assess uncertainty.

RESULTS

Fifty-two randomised controlled trials of non-bisphosphonates were included in the clinical effectiveness systematic review and an additional 51 randomised controlled trials of bisphosphonates were included in the network meta-analysis. All treatments had beneficial effects compared with placebo for vertebral, non-vertebral and hip fractures, with hazard ratios varying from 0.23 to 0.94, depending on treatment and fracture type. The effects on vertebral fractures and the percentage change in bone mineral density were statistically significant for all treatments. The rate of serious adverse events varied across trials (0-33%), with most between-group differences not being statistically significant for comparisons with placebo/no active treatment, non-bisphosphonates or bisphosphonates. The incremental cost-effectiveness ratios were > £20,000 per quality-adjusted life-year for all non-bisphosphonate interventions compared with no treatment across the range of QFracture and FRAX scores expected in the population eligible for fracture risk assessment. The incremental cost-effectiveness ratio for denosumab may fall below £30,000 per quality-adjusted life-year at very high levels of risk or for high-risk patients with specific characteristics. Raloxifene was dominated by no treatment (resulted in fewer quality-adjusted life-years) in most risk categories.

LIMITATIONS

The incremental cost-effectiveness ratios are uncertain for very high-risk patients.

CONCLUSIONS

Non-bisphosphonates are effective in preventing fragility fractures, but the incremental cost-effectiveness ratios are generally greater than the commonly applied threshold of £20,000-30,000 per quality-adjusted life-year.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018107651.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 29. See the NIHR Journals Library website for further project information.

THERAPY OF ENDOCRINE DISEASE: Denosumab vs bisphosphonates for the treatment of postmenopausal osteoporosis

The most widely used medications for the treatment of osteoporosis are currently bisphosphonates (BPs) and denosumab (Dmab). Both are antiresorptives, thus targeting the osteoclast and inhibiting bone resorption. Dmab achieves greater suppression of bone turnover and greater increases of bone mineral density (BMD) at all skeletal sites, both in naïve and pretreated patients. No superiority on fracture risk reduction has been documented so far. In long-term administration, BPs reach a plateau in BMD response after 2-3 years, especially at the hip, while BMD increases progressively for as long as Dmab is administered. Both BPs and Dmab are generally considered safe, although they have been correlated to rare adverse events, such as osteonecrosis of the jaw and atypical femoral fractures. Dmab should be preferred in patients with impaired renal function. BPs are embedded in the bone, from which they are slowly released during bone remodeling, therefore continuing to act for years after their discontinuation. In contrast, Dmab discontinuation fully and rapidly reverses its effects on bone markers and BMD and increases the risk for fractures; therefore, Dmab discontinuation should be discouraged, especially in previously treatment-naïve patients, regardless of the conventional fracture risk. In case of discontinuation, other treatment, mainly BPs, should immediately follow, although the optimal sequential treatment strategy is yet to be defined. Combination of teriparatide with Dmab or zoledronic acid, but not alendronate, provides increased BMD gains at all sites. In conclusion, both BPs and Dmab are safe and efficient therapeutic options although their particularities should be carefully considered in an individual basis.

UK clinical guideline for the prevention and treatment of osteoporosis

INTRODUCTION

In 2008, the UK National Osteoporosis Guideline Group (NOGG) produced a guideline on the prevention and treatment of osteoporosis, with an update in 2013. This paper presents a major update of the guideline, the scope of which is to review the assessment and management of osteoporosis and the prevention of fragility fractures in postmenopausal women and men age 50 years or over.

METHODS

Where available, systematic reviews, meta-analyses and randomised controlled trials were used to provide the evidence base. Conclusions and recommendations were systematically graded according to the strength of the available evidence.

RESULTS

Review of the evidence and recommendations are provided for the diagnosis of osteoporosis, fracture-risk assessment, lifestyle measures and pharmacological interventions, duration and monitoring of bisphosphonate therapy, glucocorticoid-induced osteoporosis, osteoporosis in men, postfracture care and intervention thresholds.

CONCLUSION

The guideline, which has received accreditation from the National Institute of Health and Care Excellence (NICE), provides a comprehensive overview of the assessment and management of osteoporosis for all healthcare professionals who are involved in its management.

An update of the Malaysian Clinical Guidance on the management of glucocorticoid-induced osteoporosis, 2015

OBJECTIVES

This Clinical Guidance is aimed to help practitioners assess, diagnose and manage their patients with glucocorticoid-induced osteoporosis (GIO), using the best available evidence.

METHODS

A literature search using PubMed (MEDLINE) and The Cochrane Library identified all relevant articles on GIO and its assessment, diagnosis and treatment, from 2011, to update from the 2012 edition. The studies were assessed and the level of evidence assigned. For each statement, studies with the highest level of evidence were used to frame the recommendation.

RESULTS

Consider treatment early in all patients on glucocorticoids (GC) as fracture risk increases within 3-6 months of starting GC. The decision to start treatment for GIO depends on the presence of prior fracture, category of risk (as calculated using Fracture Risk Assessment Tool), daily dose and duration of GC treatment, age, and menopausal status. General measures include adequate calcium and vitamin D intake and reducing the dose of GC to the minimum required to achieve disease control. In patients on GC with osteoporotic fractures or confirmed osteoporosis on dual-energy X-ray absorptiometry, bisphosphonates are the first-line treatment. Treatment should be continued as long as patients remain on GC. Algorithms for the management of GIO in both pre- and post-menopausal women and men have been updated.

CONCLUSIONS

In post-menopausal women and men above 50 years, bisphosphonates remain the mainstay of treatment in GIO. In pre-menopausal women and men below 50 years, bisphosphonates are recommended for those with a prevalent fracture or at very high risk only.

Biochemical markers of bone turnover in children with clinical bone fragility

BACKGROUND

The role of biochemical bone turnover markers (BTMs) in assessing low bone mass and monitoring bisphosphonate treatment in pediatric patients with clinical bone fragility is not well established. The aim of the study was to examine the correlations of BTMs and the bone mineral density (BMD), and evaluate the effects of bisphosphonates therapy on BTMs in children with clinical bone fragility.

METHODS

Clinical data of 115 patients with clinical bone fragility (mean age 9.7±5.8 years), 102 of whom received bisphosphonates, were studied. Serum alkaline phosphatase (ALP), osteocalcin (OC), urine pyridinoline (PD) and deoxypyridinoline (DPD), BMD at baseline and subsequent years were analyzed.

RESULTS

There was a significant negative correlation between urine PD and lumbar BMD (slope=-0.29, p<0.001). There were no correlations between BTMs and lumbar BMD Z-score. There was a significant positive correlation between serum OC and serum ALP, urine PD and DPD (p<0.001). Serum OC, urine PD and DPD index, as expressed as measured value/upper limit of normal value for age, decreased during the first 3 years of bisphosphonate therapy.

CONCLUSIONS

In children with clinical bone fragility, BTMs correlated with each other, but not with lumbar BMD Z-score. While they were not reliable predictors of degree of low BMD, the bone markers showed suppression during bisphosphonate therapy and may be helpful in monitoring the response to therapy.

Managing Osteoporosis in Patients on Long-Term Bisphosphonate Treatment: Report of a Task Force of the American Society for Bone and Mineral Research

Bisphosphonates (BPs) are the most commonly used medications for osteoporosis. This ASBMR report provides guidance on BP therapy duration with a risk-benefit perspective. Two trials provided evidence for long-term BP use. In the Fracture Intervention Trial Long-term Extension (FLEX), postmenopausal women receiving alendronate for 10 years had fewer clinical vertebral fractures than those switched to placebo after 5 years. In the HORIZON extension, women who received 6 annual infusions of zoledronic acid had fewer morphometric vertebral fractures compared with those switched to placebo after 3 years. Low hip T-score, between -2 and -2.5 in FLEX and below -2.5 in HORIZON extension, predicted a beneficial response to continued therapy. Hence, the Task Force suggests that after 5 years of oral BP or 3 years of intravenous BP, reassessment of risk should be considered. In women at high risk, for example, older women, those with a low hip T-score or high fracture risk score, those with previous major osteoporotic fracture, or who fracture on therapy, continuation of treatment for up to 10 years (oral) or 6 years (intravenous), with periodic evaluation, should be considered. The risk of atypical femoral fracture, but not osteonecrosis of the jaw, clearly increases with BP therapy duration, but such rare events are outweighed by vertebral fracture risk reduction in high-risk patients. For women not at high fracture risk after 3 to 5 years of BP treatment, a drug holiday of 2 to 3 years can be considered. The suggested approach for long-term BP use is based on limited evidence, only for vertebral fracture reduction, in mostly white postmenopausal women, and does not replace the need for clinical judgment. It may be applicable to men and patients with glucocorticoid-induced osteoporosis, with some adaptations. It is unlikely that future trials will provide data for formulating definitive recommendations. © 2015 American Society for Bone and Mineral Research.

The use of bisphosphonates in women: when to use and when to stop

INTRODUCTION

Bisphosphonates (BPs) are the most commonly used drugs in osteoporosis.

AREAS COVERED

This review focuses on the criteria for identifying patients who should be treated with BPs and also the rational for the duration of treatment.

EXPERT OPINION

BPs remain the mainstay for the treatment of osteoporosis. For their low cost, the treatment threshold is related exclusively to the ratio between expected benefits and the risk of side effects. This is the case of patients with prior fragility fracture or with low bone density and the presence of other relevant risk factors. The treatment should continue for 3 - 5 years or until fracture risk is no longer high. Afterward a treatment holiday should be considered on the light of the increasing risk of side effects but its duration is still controversial. The duration of this treatment holiday depends on the drug used. Discontinuation of risedronate and ibandronate is associated with the quick loss of the acquired benefits and with these two BPs discontinuation should not exceed 6 months. Alendronate and zoledronate are characterized by a persistent effect after discontinuing treatment and this would allow a more prolonged drug holiday.

Using early biomarker data to predict long-term bone mineral density: application of semi-mechanistic bone cycle model on denosumab data

Osteoporosis is a chronic skeletal disease characterized by low bone strength resulting in increased fracture risk. New treatments for osteoporosis are still an unmet medical need because current available treatments have various limitations. Bone mineral density (BMD) is an important endpoint for evaluating new osteoporosis treatments; however, the BMD response is often slower and less profound than that of bone turnover markers (BTMs). If the relationship between BTMs and BMD can be quantified, the BMD response can be predicted by the changes in BTM after a single dose; therefore, a decision based on BMD changes can be informed early. We have applied a bone cycle model to a phase 2 denosumab dose-ranging study in osteopenic women to quantitatively link serum denosumab pharmacokinetics, BTMs, and lumbar spine (LS) BMD. The data from two phase 3 denosumab studies in patients with low bone mass, FREEDOM and DEFEND, were used for external validation. Both internal and external visual predictive checks demonstrated that the model was capable of predicting LS BMD at the denosumab regimen of 60 mg every 6 months. It has been demonstrated that the model, in combination with the changes in BTMs observed from a single-dose study in men, is capable of predicting long-term BMD outcomes (e.g., LS BMD response in men after 1 year of treatment) in different populations. We propose that this model can be used to inform drug development decisions for osteoporosis treatment early via evaluating LS BMD response when BTM data become available in early trials.

A semi-mechanistic model of bone mineral density and bone turnover based on a circular model of bone remodeling

Development of novel therapies for bone diseases can benefit from mathematical models that predict drug effect on bone remodeling biomarkers. Therefore, a bone cycle model (BCM) was developed that takes into consideration the concept of the basic multicellular unit and the dynamic equilibrium of bone remodeling. The model is a closed form cyclical model with four compartments representing resorption, formation, primary mineralization, and secondary mineralization. Equations describing the time course of bone turnover biomarkers were developed using the flow rate of bone cycle units (BCU) between the compartments or the amount of BCU in each compartment. A disease progression model representing bone loss in osteoporosis, a vitamin D and calcium supplementation (placebo) model, and a drug model for antiresorptive treatments were added to the model. Initial model parameter values were derived from published bone turnover data. The BCM accurately described biomarker-time profiles in postmenopausal women receiving either placebo or bisphosphonate treatment. The slow continual increase in bone mineral density (BMD) observed after 1 year of treatment was accurately described when changes in bone turnover were combined with increases in mineralization. For this purpose, the secondary mineralization compartment was replaced by three catenary chain compartments representing increasing mineral content. The refined BCM satisfactorily predicted biomarker profiles after long-term (10-year) bisphosphonate treatment. Furthermore, the model successfully described individual bone turnover markers and BMD results following treatment with denosumab in postmenopausal women. Analyses with this model could be used to optimize dosing regimens and to predict effects of novel osteoporotic treatments.

Osteoporosis Treatment: When to Discontinue and When to Re-start

A number of effective therapies for the treatment of osteoporosis have become available in recent years. However, uncertainty exists regarding their long-term use and effectiveness. Bisphosphonate treatment, unlike hormone replacement, denosumab or teriparatide, is associated with benefits extended even after treatment discontinuation. The extended benefits are most apparent for alendronate (ALN) and zoledronate (ZOL). A drug holiday might be considered in patients at low-moderate risk and who have been fully compliant with treatment, and who have had a response to treatment. In patients at low-moderate risk of fractures the decision to consider a drug holiday should be balanced also with the safety profile of each treatment.

Treatment thresholds for osteoporosis and reimbursability criteria: perspectives associated with fracture risk-assessment tools

The definition of osteoporosis was based for several years on bone mineral density values, which were used by most guidelines for defining treatment thresholds. The availability of tools for the estimation of fracture risk, such as FRAX™ or its adapted Italian version, DeFRA, is providing a way to grade osteoporosis severity. By applying these new tools, the criteria identified in Italy for treatment reimbursability (e.g., "Nota 79") are confirmed as extremely conservative. The new fracture risk-assessment tools provide continuous risk values that can be used by health authorities (or "payers") for identifying treatment thresholds. FRAX estimates the risk for "major osteoporotic fractures," which are not counted in registered fracture trials. Here, we elaborate an algorithm to convert vertebral and nonvertebral fractures to the "major fractures" of FRAX, and this allows a cost-effectiveness assessment for each drug.

Diagnosis and management of osteoporosis in postmenopausal women and older men in the UK: National Osteoporosis Guideline Group (NOGG) update 2013

Since the launch in 2008 by the National Osteoporosis Guideline Group (NOGG), of guidance for the diagnosis and management of osteoporosis in postmenopausal women and older men in the UK there have been significant advances in risk assessment and treatment. These have been incorporated into an updated version of the guideline, with an additional focus on the management of glucocorticoid-induced osteoporosis, the role of calcium and vitamin D therapy and the benefits and risks of long-term bisphosphonate therapy. The updated guideline is summarised below. The recommendations in the guideline are intended to aid management decisions but do not replace the need for clinical judgement in the care of individuals in clinical practice.

Osteoporosis treatment: why ibandronic acid?

INTRODUCTION

In this article, we have summarized the specific evidence on ibandronic acid (or ibandronate) efficacy, tolerability, and feasibility acquired from trials and clinical use.

AREAS COVERED

This critical review focuses on evidence from randomized controlled clinical trials, meta-analyses, surrogate markers, bridging trials, long-term extension studies, observational studies, clinical experiences in osteoporosis in addition to postmenopausal treatment adherence in clinical practice, and safety profile of ibandronic acid.

EXPERT OPINION

Pivotal studies on ibandronic acid efficacy in terms of antifracture effects on nonvertebral fractures had some intrinsic limitations. However, a large body of indirect evidence suggests that ibandronate has significantly sustained vertebral and nonvertebral antifracture efficacies in women with postmenopausal osteoporosis, in comparison to those observed with other nitrogen-containing bisphosphonates. Discrepancies in efficacy between the available bisphosphonate regimens appear to be a function of dose rather than to inherent differences in their respective therapeutic potential. Drugs or treatment regimens that minimize the risk of osteoporotic fractures and make the treatment of osteoporosis more convenient and suitable for patients are preferred: ibandronic acid marketed at oral doses of 150 mg once monthly and 3 mg quarterly as intravenous injection has these characteristics. The safety profile of ibandronic acid treatment appears to be good overall and in some cases better than that of other nitrogen-containing bisphosphonates.

The role of bone turnover markers in monitoring treatment in postmenopausal osteoporosis

Bone metabolism is assessed using biochemical bone turnover markers (BTM). BTM reflect the metabolic effect of drugs on bone turnover, help to establish the lowest dose inducing the largest change in the BTM, predict treatment-related reduction in fracture risk, and are helpful in bridging studies. Changes in BTM during anti-osteoporotic therapy depend on the cellular mechanism of action of the drug, degree of change in bone turnover rate and route of administration. BTM help to establish the optimal dose of anti-osteoporotic drugs because treatment-related changes in BTM are more rapid compared with change in BMD. A greater decrease in BTM levels during the first year of tantiresorptive treatment is associated with greater antifracture efficacy over 3 years. According to preliminary data, measurement of BTM can improve persistence with anti-resorptive treatment. The use of BTM to monitor anti-osteoporotic therapy in "real life" is limited at this stage.

Prediction of changes in bone mineral density in postmenopausal women treated with once-weekly bisphosphonates

BACKGROUND

In clinical practice, bone mineral density (BMD) determined by dual-energy x-ray absorptiometry is used to monitor response to osteoporosis therapy. However, 1 to 2 yr are usually required to assess patients' BMD responses. The possibility of earlier indicators of a response or nonresponse to treatment, such as changes in bone turnover markers (BTMs), is of interest to physicians and patients.

METHODS

In this post hoc analysis of women treated with once-weekly bisphosphonates, we examined the association of tertile percentage change from baseline in BTMs at 3 or 6 months and association of several baseline clinical characteristics with 24-month percentage change from baseline in BMD and with percentage of patients showing BMD nonresponse (defined as BMD loss at two or more of four sites) at 24 months. Multivariable analysis was performed to determine which factors were independently associated with BMD nonresponse.

RESULTS

Patients in the tertile with the greatest decrease in each of the BTMs had the greatest mean increase in BMD and the lowest percentage of BMD nonresponders at 24 months. Several characteristics were independently associated with BMD nonresponse, including smaller 3-month reductions from baseline in serum C-terminal telopeptide of type 1 collagen, bone-specific alkaline phosphatase, and N-terminal propeptide of type 1 procollagen; younger age of menopause; a family history of osteoporosis; and higher baseline trochanteric BMD. Baseline BTMs were not predictive of 24-month BMD response to therapy. The strongest associations were for changes in BTMs with treatment.

CONCLUSION

In groups of patients, short-term changes in markers of bone turnover appear to be predictors of longer term BMD response and nonresponse to bisphosphonate therapy.

Skeletal accumulation of bisphosphonates: implications for osteoporosis treatment

BACKGROUND

Bisphosphonates (BPs), the gold-standard pharmacological treatment for osteoporosis, are unique in that they become physically bound to the bone matrix and therefore accumulate over time. This skeletal accumulation has important physiological implications that are not completely understood.

OBJECTIVE

To review concepts related to the biological effects of BP accumulation in the skeleton.

METHODS

Articles concerning skeletal accumulation of BP treatment were identified.

RESULTS/CONCLUSIONS

Skeletal accumulation of BP, dictated by both chemical and biological factors, is dose-dependent, differs among skeletal sites and likely differs among the various BPs. Bisphosphonate embedded within the skeletal matrix has lasting biological effects, the results of which have both positive and negative implications for bone remodeling. As alternative anti-remodeling agents gain approval for treatment of osteoporosis, the property of skeletal accumulation will likely be unique to BPs and therefore may be the property that determines the future use of this drug class.

Biochemical markers of bone turnover: potential use in the investigation and management of postmenopausal osteoporosis

INTRODUCTION

The aim was to analyse data on the use of biochemical bone turnover markers (BTM) in postmenopausal osteoporosis.

METHODS

We carried out a comparative analysis of the most important papers concerning BTM in postmenopausal osteoporosis that have been published recently.

RESULTS

The BTM levels are influenced by several factors. They are moderately correlated with BMD and subsequent bone loss. Increased levels of bone resorption markers are associated with a higher risk of fracture. Changes in the BTM during the anti-osteoporotic treatment (including combination therapy) reflect the mechanisms of action of the drugs and help to establish their effective doses. Changes in the BTM during the anti-resorptive treatment are correlated with their anti-fracture efficacy.

CONCLUSION

Biological samples should be obtained in a standardised way. BTM cannot be used for prediction of the accelerated bone loss at the level of the individual. BTM help to detect postmenopausal women who are at high risk of fracture; however, adequate practical guidelines are lacking. BTM measurements taken during the anti-resorptive therapy help to identify non-compliers. They may improve adherence to the anti-resorptive therapy and the fall in the BTM levels that exceeds the predefined threshold improves patients' persistence with the treatment. There are no guidelines concerning the use of BTM in monitoring anti-osteoporotic therapy in postmenopausal women.

Ibandronate: a new oral bisphosphonate for postmenopausal osteoporosis

OBJECTIVE

To review a new oral bisphosphonate, ibandronate, recently approved by the U.S. Food and Drug Administration for the treatment and prevention of postmenopausal osteoporosis.

DATA SOURCE

A MEDLINE/PUBMED search was conducted to identify pertinent studies in the English language. Additional references were obtained from the bibliographies of these studies. Data over the time period of 1986 through July 2005 were reviewed.

STUDY SELECTION AND DATA EXTRACTION

All studies evaluating any aspect of ibandronate in animals and humans. Studies in humans focused on the oral drug formulation.

DATA SYNTHESIS

Preclinical studies established that ibandronate was an extremely potent bisphosphonate compared with its predecessors and that it was active in all animal models of human postmenopausal and corticosteroid-associated osteoporosis. Similar to other selected bisphosphonates, preclinical studies also showed that ibandronate exhibits antitumor activity and prevents and/or reduces bone metastases. As with other oral bisphosphonates, oral bioavailability is very poor (less than 1%) and substantially reduced by administration with or proximal to cations (e.g., food, antacids, mineral supplements). Clinical trials have demonstrated the efficacy and tolerability of oral ibandronate in the treatment and prevention of postmenopausal osteoporosis when administered once daily, once weekly, and even once monthly. Ibandronate also reduces the skeletal complications of bone metastases in patients with cancer, including pain, although the dosage used is much higher than that used in osteoporosis. As with other bisphosphonates, the major tolerability issue with ibandronate is upper gastrointestinal (GI) distress (dyspepsia, pain, esophagitis, esophageal and gastric ulcers). The dosage regimen for the treatment or prevention of postmenopausal osteoporosis (the only currently approved use in the United States) is 2.5 mg once a day or 150 mg once monthly (on the same date each month). Ibandronate should not be used in the presence of severe renal impairment (creatinine clearance below 30 mL/min). The usual complex administration instructions for other oral bisphosphonates apply to ibandronate as well.

CONCLUSION

Oral ibandronate is an interesting addition to the therapeutic armamentarium for osteoporosis and cancer metastatic to bone. In fact, studies of ibandronate as an adjunctive treatment for cancers with a predilection to metastasize to bone are under way. Ibandronate has taken advantage of a complex pharmacodynamic profile in which its antiresorptive activity is independent of the frequency of dosing provided that a minimum dose-per-unit time is exceeded. Studies with every three-month dosing (and even less frequently) are under way. Whether or not the less frequent dosing of oral ibandronate will translate into a therapeutic advantage over older oral agents such as alendronate and risedronate is open to speculation. This is a difficult question to answer in the absence of head-to-head randomized controlled trials (RCTs). Older agents are still preferred until RCTs demonstrate that ibandronate is as safe and effective as these older agents.

Effect of Korean oriental medicine extract on bone mass as compared with alendronate in ovariectomized rats

A number of alternative medicines (AMs) have often been used as traditional therapies for various diseases without scientific or clinical evidence supporting their use. The present study examined the pharmaceutical effects of an AM extract with a long history of use as a traditional medicine for various bone diseases. To evaluate it as a potential candidate for use as an anti-osteoporotic drug, we investigated the effects of the AM extract on the progression of bone loss in ovariectomized (OVX) rats fed a calcium (Ca)-deficient diet for 4 or 12 weeks. We also compared the AM extract with alendronate, an anti-resorptive drug. The AM extract did not influence bone turnover as indicated by biochemical markers [i.e., deoxypyridinoline (DPD)]. In contrast, alendronate treatment seemed to reduce bone turnover via inhibition of bone resorption as evidenced by reduced urinary DPD concentrations accompanied by a tendency for decreased serum tartrate-resistant acid phosphatase. Administration of alendronate or AM extracts did not significantly affect bone density, although both tended to increase bone mineral density (BMD) and bone strength of the femur. Although both treatments did not affect vertebral BMD and bone strength, histological analysis of vertebrae showed well-developed trabecular networking in OVX rats treated with alendronate or AM extract, in contrast to the thin and disconnected trabecule in OVX rats. In conclusion, the AM extract produced a very weak effect on the prevention of bone loss induced by OVX and Ca deficiency in rats, but was similar to the results observed with alendronate. Further verification is necessary to justify the use of the AM extract as a treatment for osteoporosis.

Changes in bone density and turnover after alendronate or estrogen withdrawal

OBJECTIVE

To compare bone mineral density (BMD) and bone turnover changes after therapy withdrawal in postmenopausal women treated with alendronate or estrogen-progestin.

DESIGN

In this randomized, blinded, multinational, placebo-controlled trial, 1,609 healthy postmenopausal women ages 45 to 59 years were assigned to receive alendronate, placebo, or open-label estrogen-progestin (conjugated equine estrogens plus medroxyprogesterone acetate or a cyclic regimen of 17 beta-estradiol, norethisterone acetate and estradiol). Of the original women, one third after year 2 and one third after year 4 were switched from alendronate to placebo, while remaining blinded to treatment assignment. The women taking estrogen-progestin in years 1 to 4 were followed off therapy in years 5 and 6. BMD at the lumbar spine and hip and biochemical markers of bone turnover were measured.

RESULTS

The treatment groups described in the current report represent 860 women at baseline; 481 women entered year 5, and 430 completed 6 years. BMD steadily decreased in the placebo group during all 6 years. In contrast, spine and hip BMD increased during the first 4 years in the groups receiving daily continuous alendronate 5 mg and estrogen-progestin. During years 5 and 6, BMD decreased at the lumbar spine -2.42% (95% CI = -4.10, -0.74) and total hip -1.09% (-2.60, 0.41) in the group previously treated with alendronate 5 mg for 4 years. In comparison, large BMD decreases were observed at the spine [-7.69% (-8.96, -6.41)] and total hip [-5.16% (-6.30, -4.01)] among women who had received estrogen-progestin for 4 years.

CONCLUSION

Alendronate produces greater residual skeletal effects than estrogen-progestin after therapy discontinuation.

Pharmacokinetic Considerations in Determining the Terminal Elimination Half-Lives of Bisphosphonates

BACKGROUND AND OBJECTIVE

Bisphosphonates are commonly used to treat and prevent osteoporosis. These compounds have unusual pharmacokinetic characteristics because they bind strongly to bone, and a portion becomes buried under newly formed bone. Once incorporated into bone tissue, the subsequent release during bone remodeling is probably the rate-limiting step in the terminal elimination of bisphosphonates. Because of this unique property of bisphosphonates, pharmacokinetic studies with insufficient lengths of follow-up might entirely miss the true terminal elimination phase. A terminal half-life (t((1/2)gamma)) of approximately 11 years, similar to that of calcium and other minerals in bone, was reported from an 18-month study of alendronic acid in postmenopausal women with osteoporosis. We are not aware of any other published reports in which the elimination of a bisphosphonate has been followed for more than a few weeks post-dose. The purpose of the present study was to reanalyse the alendronic acid data to examine the effect of truncating the length of follow-up on the calculated t((1/2)gamma).

PATIENTS AND METHODS

Twenty-one postmenopausal women with osteoporosis (mean age 66 years) received intravenous alendronic acid 30mg over 4 consecutive days (7.5 mg/day), and urinary excretion of alendronic acid was monitored over the following 18-24 months. Terminal elimination half-life was originally calculated by log-linear regression of the percentage retained versus time curve between days 240 and 540 and substituting the slope of the regression line into the equation, t((1/2)gamma) = -log 2/slope. These data were reanalysed based on the period up to 30 days.

RESULTS

Data were sufficient for analysis of pharmacokinetics in 11 patients. A mean t((1/2)gamma) of approximately 11 years was reported previously, based on analysis of data between days 240 and 540. Recalculating the 'terminal' half-life of alendronic acid using only data from the first 30 days resulted in an 'observed' half-life of only 11 days.

CONCLUSION

This analysis illustrates the importance of sufficient length of follow-up to accurately characterise the true terminal elimination half-life of bisphosphonates. The relatively short (expressed in units of days rather than years) terminal elimination half-lives reported for some bisphosphonates based on only 30 days of follow-up or less are likely to substantially underestimate the true terminal elimination half-lives.

Reduction in PINP, a marker of bone metabolism, with raloxifene treatment and its relationship with vertebral fracture risk

In the Multiple Outcomes of Raloxifene Evaluation (MORE) trial, 7705 postmenopausal women with osteoporosis, defined by low bone mineral density and/or prevalent vertebral fractures (VF), were randomized to placebo or raloxifene (60 or 120 mg/day). All women received daily calcium (500 mg) and vitamin D (400-600 IU) supplements. Our previous analyses found that changes in BMD and biochemical markers of bone turnover are poorly predictive of the reduction in VF risk observed with raloxifene. This present study evaluated the effects of raloxifene on type I procollagen N-terminal propeptide (PINP), a new marker of bone turnover. Logistic regression analysis models evaluated the relationships between the changes at 1 year in PINP, serum osteocalcin (OC), bone-specific alkaline phosphatase (BSAP), and urinary excretion of type I collagen C-telopeptide fragments normalized to creatinine (CTx/Cr), and the risk of new VF at 3 years for placebo and pooled raloxifene. A subset of 967 women (mean age = 68 years) from the MORE cohort had PINP, OC, BSAP, and CTx evaluated at baseline. Both doses of raloxifene significantly decreased (P < 0.001) all biochemical markers of bone turnover from baseline. Compared to baseline, PINP levels were decreased by medians of 11.0% and 40.8% in the placebo and pooled raloxifene groups, respectively. In addition, the placebo and pooled raloxifene groups decreased serum OC by 8.5% and 31.8%, BSAP by 15.8% and 34.6%, and urinary CTx/Cr excretion by 5.6% and 46.5%, respectively, from baseline. In the pooled raloxifene group, the logistic regression relationship between 3-year VF risk and 1-year percentage change for each biochemical marker was statistically significant with PINP (slope estimate = 0.0085, P = 0.009), OC (slope estimate = 0.0068, P = 0.035), and BSAP (slope estimate = 0.0056, P = 0.039), but not with CTx/Cr (slope estimate = 0.0027, P = 0.192). Furthermore, the percent decrease in PINP at 1 year could account for 28% of the total reduction in vertebral fracture risk. In conclusion, a 1-year decrease in PINP, BSAP, or OC, but not CTx/Cr, may be predictive of the 3-year VF risk reduction with raloxifene therapy in this subset of postmenopausal women with osteoporosis.

Osteoporosis management in the new millennium

The prevalence of osteoporosis in all US postmenopausal women is 17%, and it is as high as 30% in women older than 65. All postmenopausal women should be encouraged to have adequate daily calcium and vitamin D intake, to exercise regularly, and to avoid tobacco and excessive alcohol use. Although the clinical impact and cost-effectiveness of osteoporosis screening tools remain to be established, a rational approach based on current evidence involves using National Osteoporosis Foundation guidelines, Simple Calculated Osteoporosis Risk Estimation, or Osteoporosis Risk Assessment Instrument clinical decision rules to decide when a postmenopausal woman should undergo further evaluation.

Biochemical markers for prediction of 4-year response in bone mass during bisphosphonate treatment for prevention of postmenopausal osteoporosis

Short-term changes in biochemical markers of bone turnover (bone markers) have been suggested as predictors of long-term response in bone mass during antiresorptive treatment. In the Danish cohort (n = 306) of the Early Postmenopausal Intervention Cohort (EPIC) Study (n = 1609) of oral alendronate (ALN) for prevention of postmenopausal osteoporosis, bone markers (urine C-telopeptides of type I collagen (uCTX), urine N-telopeptide cross-links of type I collagen (uNTX), serum total osteocalcin measured by ELISA [total OC (ELISA)], and serum total osteocalcin measured by RIA [total OC (RIA)]) were measured at 6-month intervals. The correlation between 6-month change in uCTX and 4-year change in spine and hip bone mineral density (BMD) was r = -0.41 and r = -0.42, respectively (P < 0.001). The corresponding values for the other bone markers were r = -0.53 and r = -0.42 (uNTX), r = -0.46 and r = -0.47 [total OC (ELISA)], and r = -0.43 and r = -0.41 [total OC (RIA)], all P < 0.001. ROC curves were used to analyse the ability of the bone markers to predict a change in spine BMD greater than 0%. The best performance [defined as the maximum value of (sensitivity plus specificity)] was found at the cut-off values of a -29% change from baseline in uCTX, a -45% change from baseline in uNTX, a -13% change from baseline in total OC (ELISA), and a -15% change from baseline in total OC (RIA). At these values the corresponding sensitivity was 66% (uCTX), 76% (uNTX), 70% [total OC (ELISA)], and 83% [total OC (RIA)]. The specificity was 80% (uCTX), 75% (uNTX), 71% [total OC (ELISA)], and 55% [total OC (RIA)]. The positive predictive value (PPV) was 82% (uCTX), 80% (uNTX), 77% [total OC (ELISA)], and 71% [total OC (RIA)]. The negative predictive value (NPV) was 64% (uCTX), 70% (uNTX), 64% [total OC (ELISA)], and 71% [total OC (RIA)]. In conclusion, the bone markers predicted a change in spine BMD greater than 0% with a high PPV and specificity. There was a trend toward better performance in this respect for the bone resorption markers.

Preventive effects of sequential treatment with alendronate and 1 alpha-hydroxyvitamin D3 on bone mass and strength in ovariectomized rats

Because accumulating evidence has shown that bisphosphonates are unable to maintain their bone-sparing effects after the withdrawal of the drug, a replacement treatment is needed when bisphosphonate treatment cannot be continued for some reason. The present study investigated the preventive effects of alendronate followed by 1alpha(OH)D3 on the mass and mechanical strength of trabecular and cortical bones in ovariectomized rats. Sprague-Dawley rats were ovariectomized or sham-operated at 48 weeks of age. Ovariectomized rats treated with vehicle alone (OVX group) showed significant decreases in bone mineral density (BMD) and mechanical strength of the lumbar vertebra and the midfemur during a 20-week period after the operation as compared with sham-operated rats. These decreases were prevented by continuous treatment with alendronate (0.5 mg/kg/day, po) for 20 weeks (ALN-C group), whereas the values reverted to those of the OVX group when alendronate was withdrawn at 10 weeks (ALN-W group). The sequential treatment with alendronate and 1alpha(OH)D3 (0.05 microg/kg/day, po) for 10 weeks each (ALN --> 1alpha group) resulted in higher BMD and mechanical strength of the lumbar vertebra and the midfemur in this group than in the OVX and ALN-W groups. The increase in mechanical strength was proportional to that in BMD at both sites, suggesting that the stimulatory effects of these treatments on bone strength were due to those on bone mass. Analyses of histology, computed tomography, and biochemical markers confirmed the preventive effects of the sequential treatment. Therefore, we propose that 1alpha(OH)D3 may be a good choice to replace alendronate when alendronate treatment cannot be continued for some reason.

Treatment of postmenopausal osteoporosis

The aim of treatment of postmenopausal osteoporosis is to reduce the frequency of vertebral and non-vertebral fractures (especially at the hip), which are responsible for morbidity associated with the disease. Results of large placebo controlled trials have shown that alendronate, raloxifene, risedronate, the 1-34 fragment of parathyroid hormone, and nasal calcitonin, greatly reduce the risk of vertebral fractures. Furthermore, a large reduction of non-vertebral fractures has been shown for alendronate, risedronate, and the 1-34 fragment of parathyroid hormone. Calcium and vitamin D supplementation is not sufficient to treat individuals with osteoporosis but is useful, especially in elderly women in care homes. Hormone replacement therapy remains a valuable option for the prevention of osteoporosis in early postmenopausal women. Choice of treatment depends on age, the presence or absence of prevalent fractures, especially at the spine, and the degree of bone mineral density measured at the spine and hip. Non-pharmacological interventions include adequate calcium intake and diet, selected exercise programmes, reduction of other risk factors for osteoporotic fractures, and reduction of the risk of falls in elderly individuals.

Association between pharmacokinetics of oral ibandronate and clinical response in bone mass and bone turnover in women with postmenopausal osteoporosis

Data from the 1-year, phase II trial of oral ibandronate for treatment of postmenopausal osteoporosis are presented (n = 180). Participants were at least 10 years past menopause and had osteopenia defined as a forearm bone mineral density at least 1.5 SD below the premenopausal mean value. Doses were 0.25, 0.50, 1.0, 2.5, or 5.0 mg daily oral ibandronate or placebo. A total of 116 women treated with ibandronate completed the study. Blood samples for pharmacokinetic analyses were drawn 20 min, 40 min, 60 min, 2 h, 4 h, and 6 h after the first and last administration of the study drug. An enzyme-linked immunosorbent assay was used to determine the concentration of ibandronic acid (BM 21.0955) in serum (Enzymun-Test System ES 600). The assay is based on streptavidine technology to fix the capture antibody to the wall of the tube. Standards were prepared for each participant using individual drug-free serum. The serum concentration-time curves of ibandronate, expressed as the area under the curve over the sampling period (AUC(0-6h)), revealed a highly significant dose-response relationship, p < 0.0001, and linear pharmacokinetic behavior. An initial half-life (T(1/2lambda1)) in serum representing distribution and early elimination was 1.3 hours. Steady-state AUC (AUC(0-6h ss)) increased by a factor of 2.5, which is consistent with an apparent elimination half-life of 32.6 h and a dosing interval of 24 h. There was an exponential association between AUC(0-6h) (ss) and the change from baseline at month 12 in the bone markers (n = 116): r = -0.37 (serum total osteocalcin), r = -0.65 (urine C-telopeptides of type I collagen), and r = -0.65 (serum C-telopeptides of type I collagen), all p < 0.0001. All bone markers were maximally depressed at values of AUC(0-6h ss) of about 3 ng h/mL. AUC(0-6h ss) furthermore revealed a logarithmic association with change from baseline at month 12 in spine BMD, r = 0.39, p < 0.0001. In conclusion, the serum concentration of ibandronate was determined validly by the enzyme-linked immunosorbent assay. The data are the first to show highly significant associations between pharmacokinetic parameters of a bisphosphonate and the clinical response in bone mass and bone turnover.

Ibandronate: a comparison of oral daily dosing versus intermittent dosing in postmenopausal osteoporosis

The objective of this study was to compare efficacy and safety of continuous versus intermittent oral dosing of ibandronate. Two hundred forty women aged 55-75 years with postmenopausal osteoporosis were randomized to active treatment or placebo. Similar total doses of ibandronate were provided by treatment regimens with either continuous 2.5 mg of ibandronate daily (n = 81) or intermittent 20 mg of ibandronate every other day for the first 24 days, followed by 9 weeks without active drug (n = 78). The placebo group (total, n = 81) was crossed over after 12 months to receive either continuous (n = 37) or intermittent ibandronate (n = 35). By 24 months, bone mineral density (BMD) had increased significantly relative to baseline in both active treatment groups. The continuous and intermittent groups showed statistically equivalent increases in lumbar spine BMD of +5.64% (+/-0.53) and +5.54% (+/-0.53) and in total hip of +3.35% (+/-0.40) and +3.41% (+/-0.40), respectively (per protocol population). Biochemical markers of bone turnover decreased significantly in both treatment groups. The level of marker suppression was similar, although the intermittent group displayed, as expected, more fluctuation over the treatment period. The frequency of adverse events was similar in the treatment groups. In conclusion, the intermittent and continuous regimens showed equivalent changes in BMD and bone turnover. These results confirm previous preclinical findings indicating that the efficacy of ibandronate depends on the total oral dose given rather than on the dosing schedule. This supports development of new flexible dosing regimens targeted to minimize the frequency of dosing, which are expected to improve convenience and lead to enhanced long-term patient compliance.

Long-term effects of withdrawal of bisphosphonate incadronate disodium (YM175) on bone mineral density, mass, structure, and turnover in the lumbar vertebrae of ovariectomized rats

This study was designed to evaluate the long-term effects of incadronate disodium (YM175) after its withdrawal on cancellous bone mass in ovariectomized (OVX) rats. Thirteen-week-old female SD rats were randomized into four groups: sham-operated, OVX, low-YM, and high-YM (0.01 mg/kg or 0.1 mg/kg subcutaneously [sc], three times a week after OVX) groups. After 4 weeks of treatment with vehicle or YM175, rats from each group were killed at time points of 0 (baseline), 3, 6, 9, and 12 months after withdrawal of the agent. Bone mineral density (BMD) of the lumbar vertebrae was measured by dual-energy X-ray absorptiometry (DXA). Bone volume (BV/TV), trabecular number and trabecular separation (Tb.N and Tb.Sp), eroded surface (ES/BS), osteoclast number and osteoclast surface (N.Oc/BS and Oc.S/BS), osteoid surface (OS/BS), and bone formation rate (BFR/BS) were measured as histomorphometric parameters of the fifth lumbar vertebra. BMD, BV/TV, Tb.N, and Tb.Sp in YM175-treated groups were maintained at the same level as in the sham group until 12 months after withdrawal in the high-YM group and until 3 months after withdrawal in the low-YM group. YM175 decreased both bone formative and resorptive parameters in histomorphometry. Serum bone-specific alkaline phosphatase (ALP) and urinary deoxypyridinoline at both doses of YM175 also showed a suppressive effect of this agent on bone turnover. These results indicate that YM175, after withdrawal, still maintains bone volume dose dependently by depressing bone resorption and formation in OVX rats. Intermittent YM175 treatment with a long interval may be sufficient to maintain the bone volume and structure in OVX rats.

Early response in biochemical markers predicts long-term response in bone mass during hormone replacement therapy in early postmenopausal women

Based on data from 153 early postmenopausal women who completed a double-blind, randomized 3 year study of graded hormone replacement therapy (HRT) doses or placebo, we investigated the value of bone markers to predict prevention of bone loss. Absolute values of serum and urinary CrossLaps (S-CTX and U-CTX) after 2 weeks of treatment were significantly correlated to 3 year bone mass response (r = -0. 28/-0.35; p < 0.001). These associations were fully expressed at 6 months (r = -0.61/-0.64; p < 0.001). Receiver operating characteristic analyses revealed that the predictive capacity of one measurement of a resorption marker after 6 months' treatment performed similarly as assessment of hip bone mass over 3 years in predicting preservation of spinal bone mass over 3 years. Comparable results were obtained using percent change from baseline in resorption markers at both 6 and 12 months, whereas for formation markers percent change was superior to absolute value at 6 months but not at 12 months. Values of accuracy for S-CTX for a cutoff of 1881 pmol/L at 6 months were 85.2% (sensitivity), 74.3% (specificity), 90.5% (positive predictive value), and 63.4% (negative predictive value); U-CTX performed similarly, whereas the values for the formation markers were slightly lower. A cutoff for S-CTX of 1245 pmol/L eliminated false-positive individuals (those who had a decrease below the cutoff but lost bone). In the false-negative group, which was composed of individuals whose S-CTX did not decrease below the cutoff but had preserved bone mass, S-CTX was significantly associated with spinal bone mass response (r = -0. 41; p < 0.01), indicating these women had been treated with a dose that was not at its optimum for their individual bone turnover. For this cutoff, the values were 49.5% (sensitivity), 97.1% (specificity), 98% (positive predictive value), and 40% (negative predictive value). In conclusion, early bone marker measurements predict long-term preservation of bone mass during HRT. Resorption markers seem superior to formation markers, which reflects that the primary effect of HRT is on bone resorption. A strategy with two cutoff levels may optimize the use of bone markers to predict bone mass response. Whether resorption markers can be used to guide individualized treatment remains to be investigated.

Clinical Utility of Biochemical Markers of Bone Remodeling

Remodeling is essential for bone health. It begins with resorption of old bone by osteoclasts, followed by the formation of new bone by osteoblasts. Remodeling is coupled (formation is linked to resorption). After middle age or perhaps beginning earlier, bone loss occurs because resorption exceeds formation. This imbalance is accentuated by estrogen deficiency as well as by many diseases and conditions. Biochemical markers that reflect remodeling and can be measured in blood or urine include resorption markers (e.g., collagen cross-links) and formation markers (e.g., alkaline phosphatase).

Bone markers exhibit substantial short-term and long-term fluctuations related to time of day, phase of the menstrual cycle, and season of the year, as well as diet, exercise, and anything else that alters bone remodeling. These biological factors, in addition to assay imprecision, produce significant intra- and interindividual variability in markers.

Bone marker measurements are noninvasive, inexpensive, and can be repeated often. Unfortunately, most of the studies that provided insight on clinical situations did not focus on markers as a primary endpoint. Bone markers have been useful in clinical practice and have been helpful in understanding the pathogenesis of osteoporosis and the mechanism of action of therapies. In clinical trials, markers aid in selecting optimal dose and in understanding the time course of onset and resolution of treatment effect. Clinical questions that might be answered by bone markers include diagnosing osteoporosis, identifying “fast bone losers” and patients at high risk of fracture, selecting the best treatment for osteoporosis, and providing an early indication of the response to treatment. Additional information is needed to define specific situations and cut points to allow marker results to be used with confidence in making decisions about individual patients.

Bone markers in clinical practice

Although biologic indices of bone turnover are widely accepted as research tools in population-based studies, their clinical utility in the management of the individual patient remains controversial. Their main limitation for a routine clinical use is related to an important biologic variability, which means that large variations (ie, in response to therapy) are needed to consider a difference between two measurements as reflecting a significant biologic change. To date, the most valuable bone markers are serum osteocalcin, bone-specific alkaline phosphatase, and the N-terminal propeptide of type 1 procollagen for bone formation and urinary measurements of the phenazopyridine crosslinks and related telopeptides for bone resorption. New serum assays for both C-telopeptide and N-telopeptide of type 1 collagen seem promising but need extensive validation. Although bone markers provide little information in the diagnosis of osteoporosis, strong evidence now shows that they can predict, albeit imperfectly, the rate of bone loss in menopausal women and the response to some antiresorptive therapies. In some populations, increased bone turnover has been shown to be a strong predictor of fracture risk, independently and to the same extent as low bone density. Whether bone markers are used to monitor the efficacy of (or compliance with) a specific treatment or to identify patients at risk for osteoporosis and thus to target preventive therapy, cost-benefit analysis, and evaluation of the potential improvement in patient outcome are clearly needed before these parameters may be universally accepted as tools to optimize patient care.

Biochemical markers of bone turnover

Biochemical markers of bone turnover that are specific to bone allow study of the subtle changes in bone turnover associated with osteoporosis. They have been evaluated in Paget's disease of the bone and chronic renal failure. This review focuses on the use of biochemical markers of bone turnover in osteoporosis. The data in this review period are numerous and varied due to the growing interest in the use of biochemical markers of bone turnover in clinical practice. The data provide support for the use of the newer bone turnover markers for monitoring treatment of osteoporosis, if care is taken to minimize sources of variability.

Bone loss in patients with inflammatory bowel disease is less than expected: a follow-up study

BACKGROUND

In spite of the accumulating evidence of an increased prevalence of osteopenia and osteoporosis in patients with inflammatory bowel diseases (IBD), the time course of bone loss is not well described, and there is little knowledge about factors indicating an increased risk of rapid bone loss.

METHODS

We conducted a follow-up study in 80 IBD patients (45 men and 25 premenopausal and 10 postmenopausal women), 19 with ulcerative colitis and 61 with Crohn disease, with a mean follow-up time of 568 +/- 60 days, to assess bone loss, risk factors of rapid bone loss, and value of bone markers to predict bone loss. Bone mineral density was measured by dual-energy X-ray absorptiometry, bone formation by bone alkaline phosphatase (BAP), and bone resorption by N-terminal telopeptide of type-I collagen (NTX) and free deoxypyridinoline (DPD).

RESULTS

Bone density changes per year were 0.46% +/- 3% at the spine, 0.06% +/- 5.1% at the femoral neck, -1.1% +/- 7.7% at the triangle of Ward, and -0.52% +/- 1.86% at total body level. Type and duration of disease, sex, age, and level of NTX, DPD, and BAP at base line did not show significant differences between patients who lost and those who did not lose bone mass. Bone loss was significantly higher in patients with (n = 28) than in those without steroids (n = 52) at the femoral neck and Ward triangle but not at the spine and total body.

CONCLUSIONS

Change in bone mass in IBD patients during short-term follow-up is low on average, but there is great heterogeneity within the population, which cannot be explained by the use of steroids alone. Bone loss cannot be predicted by analysis of bone markers.

Biochemical markers can predict the response in bone mass during alendronate treatment in early postmenopausal women. Alendronate Osteoporosis Prevention Study Group

Data from the Danish cohort (n = 67) of a multicenter trial of oral alendronate in the prevention of postmenopausal osteoporosis were used to evaluate the capacity of the biochemical markers to predict changes in bone mineral density (BMD). A panel of markers were measured: serum N-terminal midfragment osteocalcin (N-MID OC); serum total osteocalcin (total OC); bone-specific alkaline phosphatase (BSAP); serum and urine C-telopeptides of type I collagen (sCL and uCL); urine N-telopeptide crosslinks of type I collagen (NTX); and deoxypyridinoline (dPyr). The correlation between change from baseline at months 3-12 in total OC, N-MID OC, sCL, uCL, and NTX and 2 year response in spine BMD ranged from r = -0.45 to r = -0.78 (p < 0.001), and from r = -0.38 to r = 0.10 (n.s. to p < 0.002) for BSAP and dPyr. Sensitivity and specificity were used to assess the accuracy of change from baseline at month 6 in the biochemical markers for predicting prevention of bone loss in the spine over 2 years. The cutpoints used were a 30% (N-MID OC) or 50% (all other markers) decrease from baseline. Sensitivity levels were 82% (N-MID OC), 98% (total OC), 78% (sCL and NTX), and 89% (uCL). Specificities were 91% (N-MID OC), 59% (total OC), 100% (sCL), 71% (uCL), and 84% (NTX). Positive predictive values were 95% (N-MID OC), 82% (total OC), 100% (sCL), 87% (uCL), and 90% (NTX). In comparison, the predictive capacities of change from baseline at year 2 in hip BMD in predicting prevention of bone loss at the spine were similar: sensitivity, 82%; specificity, 55%; and positive predictive value, 79%. In conclusion, short-term changes in biochemical markers were valid predictors of long-term changes in BMD. Short-term changes in the sensitive biochemical markers revealed a predictive capacity similar to bone densitometry at the hip measured over 2 years. The sensitive biochemical markers offered a fast and valid alternative to bone densitometry for monitoring of alendronate treatment.