Oral ibandronate: changes in markers of bone turnover during adequately dosed continuous and weekly therapy and during different suboptimally dosed treatment regimens

Favorable impact of PD1/PD-L1 antagonists on bone remodeling: an exploratory prospective clinical study and ex vivo validation

BACKGROUND

Skeletal morbidity in patients with cancer has a major impact on the quality of life, and preserving bone health while improving outcomes is an important goal of modern antitumor treatment strategies. Despite their widespread use in early disease stages, the effects of immune checkpoint inhibitors (ICIs) on the skeleton are still poorly defined. Here, we initiated a comprehensive investigation of the impact of ICIs on bone health by longitudinal assessment of bone turnover markers in patients with cancer and by validation in a novel bioengineered 3D model of bone remodeling.

METHODS

An exploratory longitudinal study was conducted to assess serum markers of bone resorption (C-terminal telopeptide, CTX) and formation (procollagen type I N-terminal propeptide, PINP, and osteocalcin, OCN) before each ICI application (programmed cell death 1 (PD1) inhibitor or programmed death-ligand 1 (PD-L1) inhibitor) for 6 months or until disease progression in patients with advanced cancer and no evidence of bone metastases. To validate the in vivo results, we evaluated osteoclast (OC) and osteoblast (OB) differentiation on treatment with ICIs. In addition, their effect on bone remodeling was assessed by immunohistochemistry, confocal microscopy, and proteomics analysis in a dynamic 3D bone model.

RESULTS

During the first month of treatment, CTX levels decreased sharply but transiently. In contrast, we observed a delayed increase of serum levels of PINP and OCN after 4 months of therapy. In vitro, ICIs impaired the maturation of preosteoclasts by inhibiting STAT3/NFATc1 signaling but not JNK, ERK, and AKT while lacking any direct effect on osteogenesis. However, using our bioengineered 3D bone model, which enables the simultaneous differentiation of OB and OC precursor cells, we confirmed the uncoupling of the OC/OB activity on exposure to ICIs by demonstrating impaired OC maturation along with increased OB differentiation.

CONCLUSION

Our study indicates that the inhibition of the PD1/PD-L1 signaling axis interferes with bone turnover and may exert a protective effect on bone by indirectly promoting osteogenesis.

Effects of zoledronic acid on bone mineral density around prostheses and bone metabolism markers after primary total hip arthroplasty in females with postmenopausal osteoporosis

INTRODUCTION

To investigate the effect of zoledronic acid on periprosthetic bone mineral density (BMD) and bone metabolism markers after primary total hip arthroplasty in females with postmenopausal osteoporosis.

METHODS

From November 2015 to April 2016, 40 female patients who met the inclusion criteria were randomized into two groups: a control group (calcium + calcitriol) and a zoledronic acid group (calcium + calcitriol + zoledronic acid). At 1 week and 3, 6, and 12 months after operation, BMD was obtained through dual-energy X-ray absorptiometry (DEXA). At pre-operation and at 3, 6, and 12 months after the operation, levels of bone metabolism markers were obtained by serum examination.

RESULTS

Loss of BMD was significantly more pronounced in the control group than in the ZOL group in zones 1, 4, 6, and 7 at 6 months and in zones 1, 2, 4, 6, and 7 at 12 months after the operation. The levels of bone-resorption marker (β-CTX) were significantly lower in the ZOL group than in the control group at 3, 6, and 12 months after operation. The levels of bone-formation marker (TP1NP) performed statistically differences only at 12 months after the operation in these two groups.

CONCLUSIONS

Receiving an intravenous infusion of 5 mg zoledronic acid after THA can effectively reduce periprosthetic BMD loss and improve bone remodeling in females with postmenopausal osteoporosis. Zoledronic acid significantly inhibited bone mass loss in zones 1, 2, 4, 6, and 7 after THA and inhibited bone-resorption marker (β-CTX) to improve bone remodeling. Zoledronic acid treatment is potentially important for patients with osteoporosis after THA.

Ibandronate: its pharmacology and clinical efficacy in the management of tumor-induced hypercalcemia and metastatic bone disease

It is well accepted that tumor cells in the bone, especially from breast cancer, prostate cancer and multiple myeloma, can stimulate osteoclast formation and activity. Bisphosphonates are potent inhibitors of osteoclast-mediated normal and pathologic bone resorption. Besides their apoptotic and antiproliferative activity on osteoclasts, bisphosphonates can also exert similar effects on macrophages and tumor cells. Currently, it is unknown if this effect can be translated into clinical practice with regard to an effective adjuvant therapeutic regimen for high-risk patients with systemic recurrences following primary treatment of a given cancer. There are several new aspects that might extend the clinical use of ibandronate, a bisphosphate, in oncology: prevention of hypogonadal osteoporosis in men, palliative management of painful osseous metastases and adjuvant therapy of high-risk prostate cancer patients. Safety and tolerability are excellent for the oral and intravenous formulations, and ibandronate can even be safely applied in pre-existing renal insufficiency. The purpose of this review is to critically reflect the pharmacology and clinical efficacy of ibandronate in the management of tumor-induced hypercalcemia, osteoporosis and metastatic bone disease.

Adherence to raloxifene therapy: assessment methods and relationship with efficacy

Response to therapy depends on patient compliance but accurate assessment is difficult and adequate levels of adherence are uncertain. Adherence to raloxifene treatment may be assessed more accurately by electronic monitoring than by counting returned tablets. The level of adherence is positively associated with the degree of bone response.

INTRODUCTION

Adherence to study medication is usually estimated by counting returned tablets. This method relies on subjects' honesty and may be inaccurate. We aimed to assess adherence more accurately, and examine its effect on measures of bone response, by using electronic monitoring.

METHODS

Osteopenic women, ages 50 to 80, were prescribed daily raloxifene for 2 years. Electronic bottle caps (Medication Event Monitoring System (MEMS), Aardex) recorded the date and time on opening. Returned tablets were also counted. We measured bone mineral density (BMD) in duplicate at the spine and hip at baseline and 2 years. We also measured urinary N-terminal cross-linked telopeptide of type I collagen (NTX) at baseline, 1 and 2 years. We calculated the percentage changes in BMD and NTX from mean baseline to mean follow up measurements. Percentage adherence was assessed by both methods for 71 subjects that completed the study.

RESULTS

The two methods correlated significantly (p <0.001, Spearman's rho = 0.73) but the tablet count showed a higher median adherence than the MEMS caps (95.7 vs. 85.0%, p <0.001), with greater divergence at lower adherence levels. MEMS adherence in 65 subjects with complete data correlated with NTX response (p <0.01, rho = -0.33) but with BMD response only at the femoral neck. However, adherence in the lowest quartile was associated with poorer BMD response at all sites (p <0.05).

CONCLUSION

Tablet counts may give similar results overall but conceal substantial individual non-adherence. Monitoring caps may assess adherence more accurately than tablet counts and would be the preferred method in clinical trials. The degree of adherence is associated with both bone turnover and BMD responses to anti-resorptive therapy.

Bisphosphonates for periprosthetic bone loss after joint arthroplasty: a meta-analysis of 14 randomized controlled trials

The present meta-analysis aimed to evaluate the middle-term efficacy of bisphosphonates on maintaining periprosthetic bone mass after joint arthroplasty and the potential influential factors. It was found that the protective effect of bisphosphonates, probably modified by its generation and the prosthesis location, could persist in a middle-term follow-up after surgery and after drug discontinuation.

INTRODUCTION

A previous meta-analysis of 6 RCTs with follow-up of 12 months suggested that bisphosphonates (BPs) could prevent bone loss after arthroplasty up to 6 months. Our meta-analysis based on 14 RCTs involving 671 patients with follow-up up to 72 months aimed to evaluate the middle-term efficacy of BPs, understand the sources of heterogeneity, and comprehensively identify the potential influential factors.

METHODS

Electronic databases searching and hand searching of conference proceedings were conducted. We evaluated the methodological quality and abstracted relevant data. With fixed effect model we calculated the weighted mean differences to evaluate bone mineral density at different time points. We also conducted a systematic review for BP-related adverse effects.

RESULTS

The significantly less periprosthetic bone loss occurred in the BP-treated group than in the control group at 3, 6, and 12 months, and between 24 and 72 months after the index surgery. The protective effect persisted during 18 to 70 months after discontinuation of BPs. The heterogeneity was minimized with the separation of hip and knee trials during the analysis. The efficacy was more potent for the second and the third generation of BPs than the first generation. None of the trials noted serious or fatal adverse effects related to BPs.

CONCLUSIONS

The overall moderate evidence from the RCTs confirmed the significantly short-term and middle-term efficacy of BPs on periprosthetic bone loss after joint arthroplasty. To obtain a better efficacy, the second and the third generation of BPs may be the choice.

Effects of pharmaceutical care on adherence and persistence to bisphosphonates in postmenopausal osteoporotic women

WHAT IS KNOWN AND OBJECTIVE

Studies have shown that comprehensive interventions by pharmacists can improve adherence and persistence to osteoporosis therapy, but the association between adherence and bone turnover markers (BTMs) has never been studied. Therefore, the aim of this study was to evaluate the effects of pharmaceutical care on medication adherence (and its effects on BTMs), as well as persistence of postmenopausal osteoporotic women to prescribed bisphosphonates.

METHODS

A randomized controlled trial was conducted from 2005 to 2009 in the University Malaya Medical Centre, Malaysia.

INCLUSION CRITERIA

postmenopausal osteoporotic women diagnosed with osteoporosis with a T-score ≤ -2·5 or who had a low-trauma fracture and prescribed weekly alendronate/risedronate. Intervention participants received counselling on osteoporosis, risk factors, lifestyle modifications, goals of therapy, side effects and the importance of adherence. Adherence was assessed at months 3, 6 and 12, and persistence at month 12. Feedback on BTMs was provided at months 4 and 7. The control group received no counselling. Two BTMs were used: serum C-terminal cross-linking telopeptide of type I collagen (CTX-I) and serum osteocalcin (OC).

MAIN OUTCOMES MEASURED

medication adherence, BTMs and persistence.

RESULTS AND DISCUSSION

Intervention participants who received pharmaceutical care reported significantly higher medication adherence at 6 (P = 0·015) and 12 months (P = 0·047) compared with the control group; but this effect was not shown by the BTMs. This is probably due to the long effect of bisphosphonates in bone. A significant difference was found between serum CTX-I and OC in identifying non-responders to anti-resorptive therapy (P < 0·001), indicating the usefulness of BTMs as an objective marker. However, pharmaceutical care did not affect persistence to osteoporosis therapy within a 1-year period [log rank (Mantel-Cox) χ² = 0·496, P = 0·481]. The proportion of participants who were persistent with bisphosphonate therapy after 12 months was 89·8% and 87·0% in the control and intervention group respectively.

WHAT IS NEW AND CONCLUSION

The provision of pharmaceutical care improved medication adherence but not persistence. BTMs were not appropriate objective measures for assessing adherence to weekly bisphosphonates but were useful for identifying non-responders to treatment within 3-6 months, much earlier than using bone mineral density. The study indicates that pharmacists have a role in improving medication adherence, but its long-term effect on persistence warrants further studies with longer duration.

Bone-turnover markers in fracture healing

Biochemical markers of bone-turnover have long been used to complement the radiological assessment of patients with metabolic bone disease. Their implementation in daily clinical practice has been helpful in the understanding of the pathogenesis of osteoporosis, the selection of the optimal dose and the understanding of the progression of the onset and resolution of treatment. Since they are derived from both cortical and trabecular bone, they reflect the metabolic activity of the entire skeleton rather than that of individual cells or the process of mineralisation.

Quantitative changes in skeletal-turnover can be assessed easily and non-invasively by the measurement of bone-turnover markers. They are commonly subdivided into three categories; 1) bone-resorption markers, 2) osteoclast regulatory proteins and 3) bone-formation markers. Because of the rapidly accumulating new knowledge of bone matrix biochemistry, attempts have been made to use them in the interpretation and characterisation of various stages of the healing of fractures. Early knowledge of the individual progress of a fracture could help to avoid delayed or nonunion by enabling modification of the host’s biological response.

The levels of bone-turnover markers vary throughout the course of fracture repair with their rates of change being dependent on the size of the fracture and the time that it will take to heal. However, their short-term biological variability, the relatively low bone specificity exerted, given that the production and destruction of collagen is not limited to bone, as well as the influence of the host’s metabolism on their concentration, produce considerable intra- and inter-individual variability in their interpretation. Despite this, the possible role of bone-turnover markers in the assessment of progression to union, the risks of delayed or nonunion and the impact of innovations to accelerate fracture healing must not be ignored.

New and emerging treatments for osteoporosis

A variety of new treatments for osteoporosis have become available within the last several years, and a number of emerging treatments remain in late clinical stage development. New and emerging treatments include more potent members, or more convenient formulations, of existing classes of therapy, but a number of the emerging treatments are first-generation compounds addressing specific therapeutic targets based on recent advances in understanding of basic bone biology. These new and emerging treatments include agents with anticatabolic effects, compounds with anabolic effects, and one agent possibly containing both anticatabolic and anabolic effects. The increasing variety of new and emerging treatments increases the possibility that effective therapy will be targeted to the specific needs of the individual patient.

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

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

Clinical application of biochemical markers of bone turnover

With the ageing population in most countries, disorders of bone and mineral metabolism are becoming increasingly relevant to every day clinical practice. Consequently, the interest in, and the need for effective measures to be used in the screening, diagnosis and follow-up of such pathologies have markedly grown. Together with clinical and imaging techniques, biochemical tests play an important role in the assessment and differential diagnosis of metabolic bone disease. In recent years, the isolation and characterisation of cellular and extracellular components of the skeletal matrix have resulted in the development of molecular markers that are considered to reflect either bone formation or bone resorption. These biochemical indices are non-invasive, comparatively inexpensive and, when applied and interpreted correctly, helpful tools in the diagnostic and therapeutic assessment of metabolic bone disease. This review provides an overview of the current evidence regarding the clinical use of biochemical markers of bone remodelling in bone disease, with an emphasis on osteoporosis.

Ibandronate, an experimental intravenous bisphosphonate for osteoporosis, bone metastases, and hypercalcemia of malignancy

Ibandronate is an experimental intravenous bisphosphonate under study for the prevention or treatment of osteoporosis and skeletal complications of bone metastases, as well as hypercalcemia of malignancy. To review the data on this drug, PubMed/MEDLINE was searched for pertinent studies in English; data from January 1986-October 2005 were reviewed. In preclinical studies, ibandronate was an extremely potent bisphosphonate compared with its predecessors and was active in all animal models of human postmenopausal and corticosteroid-associated osteoporosis. Similar to other bisphosphonates, ibandronate exhibits antitumor activity and prevents or reduces bone metastases. Forty to fifty percent of the dose is bound to bone; renal clearance of unchanged drug accounts for 70% of total body clearance. Early clinical trials demonstrated efficacy and tolerability of intravenous ibandronate in the prevention or treatment of postmenopausal and corticosteroid-associated osteoporosis when administered once every 3 months. Intravenous ibandronate also reduces skeletal complications of bone metastases, including pain, although the cumulative dose used is much higher than that used in osteoporosis, as the drug is administered every 3-4 weeks. Single doses of intravenous ibandronate are probably also effective in the treatment of hypercalcemia of malignancy. The major tolerability issue with intravenous bisphosphonates is renal safety, thus the drugs generally require infusion (e.g., 0.25 hr for zoledronic acid, 2-24 hrs for pamidronate). However, intravenous ibandronate can be administered by bolus injection over a few minutes without an elevated risk of nephrotoxicity. The experimental intravenous dosage is 2 mg every 3 months for treatment or prevention of osteoporosis, and 2-6 mg every 3-4 weeks or in a single dose for treatment of bone metastases or hypercalcemia of malignancy, respectively. Ibandronate can be used in the presence of severe renal impairment with proper dosage adjustment. The drug will be an interesting addition to the available drugs for osteoporosis, bone metastases, and hypercalcemia of malignancy. Studies of intravenous ibandronate as an adjunctive treatment for cancers that tend to metastasize to bone are under way. Whether intravenous ibandronate will be a therapeutic advance is best answered by randomized, controlled trials. These are ongoing and should provide data with which to make better-informed choices concerning intravenous bisphosphonates.

Drug insight: Bisphosphonates for postmenopausal osteoporosis

Bisphosphonates are potent antiresorptive agents, which have largely been used for the treatment of postmenopausal osteoporosis during the past 10 years. When embedded in bone matrix, bisphosphonates are taken up by osteoclasts engaged in bone resorption, leading--mainly by inhibition of farnesyl diphosphate synthase, a key enzyme of the mevalonate pathway--to osteoclast apoptosis. Bone resorption decreases, with consequent improvement in the mechanical properties of bone and a reduced risk of fracture. Alendronate and risedronate are oral nitrogen-containing bisphosphonates. Several randomized, placebo-controlled trials have shown the ability of these bisphosphonates to halve the risk of vertebral fracture when taken daily for 3 years. Nonvertebral fracture risk, including that at the hip, was also significantly decreased. Weekly regimens have simplified the administration of bisphosphonates and, probably, improved adherence to treatment. A significant reduction in the risk of vertebral fracture has also been demonstrated with an intermittent regimen of ibandronate, which is a new, potent, nitrogen-containing bisphosphonate. Ibandronate was recently marketed for use in an oral, once-monthly dose of 150 mg, with the goal of improving compliance. Bisphosphonates are usually well tolerated in the long term. Intravenous administration of bisphosphonates in women with osteoporosis, which is currently under investigation, might be an interesting future option for women who cannot tolerate oral regimens, and for enhancing compliance.

An update on biomarkers of bone turnover and their utility in biomedical research and clinical practice

BACKGROUND

Maintenance of the structural and functional integrity of the skeleton is a critical function of a continuous remodeling driven by highly associated processes of bone resorption and synthetic activities driven by osteoclasts and osteoblasts, respectively. Acceleration of bone turnover, accompanied with a disruption of the coupling between these cellular activities, plays an established role in the pathogenesis of metabolic bone diseases, such as osteoporosis. During the past decades, major efforts have been dedicated to the development and clinical assessment of biochemical markers that can reflect the rate of bone turnover. Numerous studies have provided evidence that serum levels or urinary excretion of these biomarkers correlate with the rate of bone loss and fracture risk, proving them as useful tools for improving identification of high-risk patients.

OBJECTIVE

The aim of the present review is to give an update on biomarkers of bone turnover and give an overview of their applications in epidemiological and clinical research.

DISCUSSION

Special attention is given to their utility in clinical trials testing the efficacy of drugs for the treatment of osteoporosis and how they supplement bone mass measurements. Recent evidence suggests that biochemical markers may provide information on bone age that may have indirectly relates to bone quality; the latter is receiving increasing attention. A more targeted use of biomarkers could further optimize identification of high-risk patients, the process of drug discovery, and monitoring of the efficacy of osteoporosis treatment in clinical settings.

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.

Oral ibandronate in the management of postmenopausal osteoporosis: Review of upper gastrointestinal safety

Oral daily bisphosphonates carry a potential for gastrointestinal (GI) adverse events, which has been partly addressed by introducing once-weekly regimens. Nevertheless, the need to follow inconvenient dosing instructions every week could still hinder long-term compliance and therapeutic outcome. In addition, survey data indicates that many patients would prefer a once-monthly rather than once-weekly bisphosphonate dosing regimen. Ibandronate is a potent, nitrogen-containing bisphosphonate specifically developed for less frequent administration. In a pivotal study in postmenopausal osteoporosis, oral ibandronate, administered daily or with a between-dose interval of >2 months, demonstrated robust antifracture efficacy and an overall incidence of upper GI adverse events similar to placebo, even in patients at increased risk of such events. This and other clinical studies conducted in postmenopausal women demonstrate that oral ibandronate has an excellent upper GI safety profile.

Adherence and persistence: impact on outcomes and health care resources

Non-adherence to and poor persistence with antiresorptive medication are significant problems in preventing adverse consequences of osteoporosis. Adherence rates for oral bisphosphonate therapy drop off dramatically during the first year of treatment and continue to decline thereafter. Inadequate adherence is associated with smaller decreases in rate of bone turnover, smaller bone mineral density (BMD) gains, and greater risk of fracture. Measures to improve patient adherence include improved physician/patient communication, close monitoring, and early intervention in declining adherence. Another approach is strengthening of patient commitment through reinforcement of the connection between treatment response and quality of life benefits. Use of biochemical markers of response or BMD measurements to illustrate response to patients may be useful in this regard. Simplification of treatment regimens would also be of considerable value in improving adherence and persistence.

Ibandronate: the evolution of a once-a-month oral therapy for postmenopausal osteoporosis

Bisphosphonates have been shown to be highly effective in preventing and treating postmenopausal osteoporosis (PMO) and the associated risk of fracture. However, poor adherence with bisphosphonate therapies for PMO results in a high incidence of otherwise preventable fractures. The chronicity of this condition requires long-term treatment, but fewer than one in two women remains on daily bisphosphonate therapy for 1 yr. A good way to reduce the risk of osteoporotic fractures is through development of equally efficacious formulations with more convenient dosing regimens. Weekly formulations of bisphosphonates have been introduced that demonstrate comparable efficacy to daily formulations with slightly improved adherence. Recently, a new formulation utilizing a third-generation nitrogen-containing bisphosphonate--ibandronate--has been approved with a monthly dosing regimen. The pharmacokinetics and high potency of ibandronate, similar with other bisphosphonates, facilitate lower mg doses and longer-interval dosing frequencies with similar efficacy and enhanced tolerability. Preclinical studies and clinical trials have consistently demonstrated that it is the total cumulative dose of ibandronate that determines efficacy. The convenience of once-monthly dosing may ultimately improve adherence and clinical outcomes among the growing population of postmenopausal women at risk of osteoporosis.

Oral antiresorptive therapy

Oral antiresorptive agents play a pivotal role in the management of osteoporosis. This paper discusses the effects and potential future role of newer agents such as ibandronate. Alternative dosing schedules and routes of administration have become available and may improve fracture protection, compliance, and tolerability for the long term treatment of a chronic condition such as osteoporosis. Increasingly these agents are being used to reduce bone loss in other diseases associated with high risk for osteoporosis such as organ transplantation and cystic fibrosis. Such studies may act as prototypes for the extended use of this class of drugs in other chronic inflammatory disease states. The innovative, yet disappointing results from combining an antiresorptive agent (alendronate) with the anabolic effects of teriparatide is also discussed. The major problem that remains is the lack of direct comparison between the agents in terms of fracture endpoints.

Clinical Pharmacology of Potent New Bisphosphonates for Postmenopausal Osteoporosis

Bisphosphonates are potent inhibitors of bone resorption, used in most bone diseases associated with high bone resorption levels. Several bisphosphonates, developed to prevent and treat postmenopausal osteoporosis, increase bone mineral density and decrease biochemical markers of bone turnover, and more importantly, reduce fracture risk. Alendronate and risedronate have proven their efficacy to reduce vertebral and hip fracture risk among postmenopausal osteoporotic women, using daily regimens. Weekly intermittent schedules, however, are now most commonly prescribed, because they have shown pharmacologic equivalence to the daily regimen. Ibandronate has been the first bisphosphonate to demonstrate vertebral fracture risk reduction using an intermittent regimen. Studies using ibandronate as intravenous injections every 3 months are under way. Zoledronic acid may also be an attractive option for the treatment of postmenopausal osteoporosis if a large ongoing trial proves that a single annual injection of this compound allows osteoporotic fracture risk reduction.

Nouveaux traitements de l'ostéoporose

New intermittent regimens with bisphosphonates such as oral ibandronate, and maybe annual intra-venous zoledronate, will be useful additions to the treatment of post-menopausal osteoporosis. Strontium ranelate is a new molecule that both inhibits bone resorption and stimulates bone formation, with proven efficacy to reduce fracture incidence. Teriparatide (1-34 fragment of parathyroid hormone), using daily subcutaneous injections, has also proven its efficacy to decrease vertebral and peripheral fracture risk in postmenopausal osteoporotic women. In the next five years, new SERMs and inhibitors of RANK-ligand might be new treatment options.

Effective doses of ibandronate do not influence the 3-year progression of aortic calcification in elderly osteoporotic women

Animal experiments revealed conflicting results as to the impact of bisphosphonate treatment on atherosclerosis and related vascular calcification. The effect of long-term treatment with clinical doses of bisphosphonates on aortic calcification (AC) in an "at-risk" population of osteoporotic elderly women has not been assessed systematically. In the present analysis including 474 women (55-80 years) participating in two 3-year randomized, placebo-controlled clinical trials, we assessed the simultaneous impact of ibandronate given either orally (2.5 mg daily or 20 mg intermittently) or intravenously (0.5 mg or 1.0 mg IV every 3 months) on bone mass and AC. All women received calcium and vitamin D supplements. Bone mineral density (BMD) was measured at the lumbar spine and the total hip using dual-energy X-ray absorptiometry (DXA). Calcified deposits of the lumbar aorta (L1-L4) were visualized on lateral radiographs and severity was graded by a validated scoring system. Measurements were performed at baseline and at years 1, 2, and 3. At baseline, there was a significant inverse correlation between the severity of AC and BMD at the hip (r=-0.151, P=0.003), but not at the lumbar spine. The two oral doses and the 1.0 mg IV dose evoked statistically significant increases in both hip and spine BMD compared with placebo, whereas the effect of 0.5 mg was significant only at the hip (P<0.05). No differences in the yearly rate of progression or the 3-year change in AC was observed between the different intervention groups. Furthermore, there were no statistically significant correlations between the 3-year change in BMD and the simultaneous change in AC. These findings thus suggest that 3-year treatment with effective doses of ibandronate does not pose any cardiovascular risk in terms of altering vascular calcification.

Efficacy and safety of ibandronate given by intravenous injection once every 3 months

Oral bisphosphonates are established therapeutics for postmenopausal osteoporosis. Alternative, simplified dosing regimens that improve tolerability and promote convenience may be advantageous. Ibandronate is a highly potent, nitrogen-containing bisphosphonate that can be administered as a convenient intravenous (i.v.) injection (over 15-30 s) in schedules featuring extended between-dose intervals. In a recent fracture prevention study, 1 and 0.5 mg i.v. ibandronate injections, given once every 3 months, were shown to dose-dependently increase lumbar spine and hip bone mineral density (BMD) and decrease biochemical markers of bone turnover in women with postmenopausal osteoporosis, but the overall magnitude of efficacy provided by both doses was suboptimal. In the present study (Intermittent Regimen intravenous Ibandronate Study: the IRIS study), the dose-response relationship with intermittent intravenous ibandronate injections was further evaluated in 520 postmenopausal osteoporotic women (aged 55-75 years, time since menopause >or= 5 years, lumbar spine [L1-L4] BMD T score < -2.5). At enrolment, participants were randomized to receive either 2 mg (n = 261) or 1 mg (n = 131) ibandronate or placebo (n = 128) intravenous injections, given once every 3 months. After 1 year, ibandronate therapy produced substantial and dose-dependent increases in lumbar spine and hip BMD, and decreases in biochemical markers of bone turnover, with the 2 mg dose providing significantly greater efficacy than the 1 mg dose. Most notably, lumbar spine BMD increased by 5.0% and 2.8% in the 2 and 1 mg groups, respectively, and decreased by 0.04% in the placebo group. Furthermore, total hip BMD increased by 2.9%, 2.2%, and 0.6%, respectively. Serum and urinary CTX, reflecting bone resorption, were decreased by 62.5% and 61%, respectively, with the 2 mg dose, and by 43.5% and 42%, respectively, with the 1 mg dose. Intravenous ibandronate was well tolerated with a similar incidence of adverse events to placebo. Importantly, no indicators of renal toxicity were reported. In summary, the 2 mg ibandronate regimen provides significantly greater BMD increases and significantly greater suppression of bone resorption markers than the 1 mg dose used in this study and in the previous fracture prevention study. Ongoing studies aim to further establish the efficacy and convenience of intermittent intravenous ibandronate injections in postmenopausal osteoporosis.