Long-term effects of a treatment course with oral alendronate of postmenopausal osteoporosis

Therapeutic Treatments for Osteoporosis-Which Combination of Pills Is the Best among the Bad?

Osteoporosis is a chronical, systemic skeletal disorder characterized by an increase in bone resorption, which leads to reduced bone density. The reduction in bone mineral density and therefore low bone mass results in an increased risk of fractures. Osteoporosis is caused by an imbalance in the normally strictly regulated bone homeostasis. This imbalance is caused by overactive bone-resorbing osteoclasts, while bone-synthesizing osteoblasts do not compensate for this. In this review, the mechanism is presented, underlined by in vitro and animal models to investigate this imbalance as well as the current status of clinical trials. Furthermore, new therapeutic strategies for osteoporosis are presented, such as anabolic treatments and catabolic treatments and treatments using biomaterials and biomolecules. Another focus is on new combination therapies with multiple drugs which are currently considered more beneficial for the treatment of osteoporosis than monotherapies. Taken together, this review starts with an overview and ends with the newest approaches for osteoporosis therapies and a future perspective not presented so far.

Beneficial effects of switching to denosumab from bisphosphonates or selective estrogen receptor modulators in postmenopausal women with type 2 diabetes and osteopenia/osteoporosis

AIMS/INTRODUCTION

Patients with type 2 diabetes mellitus have a higher bone fracture risk than patients without diabetes. Although denosumab (Dmab) is a potent bone resorption inhibitor, its efficacy in patients with type 2 diabetes mellitus has not been elucidated. In this study, we investigated the effects of switching to Dmab from bisphosphonates (BP) or a selective estrogen receptor modulator (SERM) in postmenopausal type 2 diabetes mellitus patients.

MATERIALS AND METHODS

This was a three medical institutions, prospective, observational study for postmenopausal patients with type 2 diabetes mellitus whose T-score of femoral neck or lumbar spine bone mineral density was under -1.0 standard deviation, even after >6 months of BP or SERM administration. After obtaining consent, participants were treated for osteopenia/osteoporosis by either continuing BP (BP-BP group)/SERM (SERM-SERM group), or by switching to Dmab (BP-Dmab or SERM-Dmab groups). Changes in bone mineral density and bone metabolism marker levels were evaluated after 6 months.

RESULTS

A total of 48 patients were included in this study, and each group comprised 12 patients. No significant difference existed in baseline characteristics among the groups. The average age and glycated hemoglobin were 71 ± 8 years and 7.2 ± 0.9%, respectively. In the SERM-Dmab group, lumbar spine bone mineral density was significantly increased by 5.0% compared with the SERM-SERM group (P < 0.04). Serum bone-specific alkaline phosphatase and tartrate-resistant acid phosphatase 5b were significantly decreased in the BP-Dmab and SERM-Dmab groups compared with the BP-BP and SERM-SERM groups, respectively.

CONCLUSIONS

Switching to Dmab from BP or SERM is beneficial to prevent osteoporosis progression in postmenopausal patients with type 2 diabetes mellitus patients.

Decreased serum undercarboxylated osteocalcin is associated with cognitive impairment in male patients with type 2 diabetes

BACKGROUND

Basic and clinical researches have suggested that type 2 diabetes (T2DM) is associated with cognitive impairment, and diabetes mellitus increases the risk of cognitive impairment and dementia. Recently, some reports found that undercarboxylated osteocalcin (ucOC) could affect brain functions, and decreased in patients with T2DM. We aimed to investigate the association of serum ucOC with cognitive impairment in T2DM patients.

METHODS

A total of 196 male T2DM patients without medications known to affect bone metabolism or history of bone fracture, aged ≥18years were recruited and divided into impaired cognition group and normal cognition group. We use the scores of Minimum Mental State Examination (MMSE) to evaluate the subjects' cognitive function. Detailed cognitive performance was also evaluated by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Serum ucOC was measured by Enzyme-Linked Immunosorbent Assay (ELISA) kit.

RESULTS

Compared to male T2DM patients with normal cognition, the mean osteocalcin concentrations were significantly lower in male T2DM patients with impaired cognition (P<0.05). RBANS total and all indexes scores were also lower in patients with impaired cognition (all P<0.05). After adjusted effects of confounding factors, serum ucOC was positively correlated with a variety indexes of RBANS except visuospatial/constructional.

CONCLUSIONS

The serum ucOC is positively correlated with RBANS scores in male T2DM patients. It suggests that serum ucOC may be involved in the development and progression of cognitive dysfunction in T2DM patients.

Cost-Effectiveness of Osteoporosis Screening and Treatment with Hormone Replacement Therapy, Raloxifene, or Alendronate

Recent information about osteoporosis treatments and their nonfracture side effects suggests the need for a new costeffectiveness analysis. The authors estimate the cost effectiveness of screening women for osteoporosis at age 65 and treating those who screen positive with hormone replacement therapy (HRT), raloxifene, or alendronate. A Markov model of osteoporosis disease progression simulates costs and outcomes of women aged 65 years. Incremental cost effectiveness ratios of screen-and-treat strategies are calculated relative to a no-screen, no-treat (NST) strategy. Disease progression parameters are derived from clinical trials; cost and quality-of-life parameters are based on review of cost databases and cost-effectiveness studies. Women are screened using dual-energy x-ray absorptiometry, and women screening positive are treated with HRT, raloxifene, or alendronate. Screening and treatment with HRT increase costs and lower quality-adjusted life years (QALYs; relative to the NST strategy). The only scenario (of several) in the sensitivity analysis in which HRT increases QALYs is when it is assumed that there are no drug-related (nonfracture) health effects. Raloxifene increases costs and QALYs; its cost-effectiveness ratio is $447,559 per QALY. When prescribed for the shortest duration modeled, raloxifene’s cost-effectiveness ratio approached $133,000 per QALY. Alendronate is the most cost-effective strategy; its cost-effectiveness ratio is $72,877 per QALY. Alendronate’s cost-effectiveness ratio approaches $55,000 per QALY when treatment effects last for 5 years or the discount rate is set to zero. The authors conclude that screening and treating with alendronate are more costeffective than screening and treating with raloxifene or HRT. Relative to an NST strategy, alendronate has a fairly good cost-effectiveness ratio

Duration of treatment in postmenopausal osteoporosis: how long to treat and what are the consequences of cessation of treatment?

Although a variety of medications are effective for the treatment of postmenopausal osteoporosis, there is concern that long-term use may incur side effects. Consequently, some have proposed discontinuing or temporarily suspending treatment after a defined period of time. As the benefits of fracture risk reduction may recede during this "drug holiday", the clinician may be faced with deciding when to resume therapy (and with which agent) while avoiding the possible cumulative risk of side effects. This article summarizes data regarding length of treatment and the effects of cessation of treatment on bone density, bone turnover markers, and fracture risk.

Bisphosphonate effects on bone turnover, microdamage, and mechanical properties: what we think we know and what we know that we don't know

The bisphosphonates (BPs) have been useful tools in our understanding of the role that bone remodeling plays in skeletal health. The purpose of this paper is to outline what we know, and what is still unknown, about the role that BPs play in modulating bone turnover, how this affects microdamage accumulation, and ultimately what the effects of these changes elicited by BPs are to the structural and the material biomechanical properties of the skeleton. We know that BPs suppress remodeling site-specifically, probably do not have a direct effect on formation, and that the individual BPs vary with respect to speed of onset, duration of effect and magnitude of suppression. However, we do not know if these differences are meaningful in a clinical sense, how much remodeling is sufficient, the optimal duration of treatment, or how long it takes to restore remodeling to pre-treatment levels following withdrawal. We also know that suppression is intimately tied to microdamage accumulation, which is also site-specific, that BPs impair targeted repair of damage, and that they can reduce the energy absorption capacity of bone at the tissue level. However, the BPs are clearly effective at preventing fracture, and generally increase bone mineral density and whole bone strength, so we do not know whether these changes in damage accumulation and repair, or the mechanical effects at the tissue level, are clinically meaningful. The mechanical effects of BPs on the fatigue life of bone, or BP effects on bone subject to an impact, are entirely unknown. This paper reviews the literature on these topics, and identifies gaps in knowledge that can be addressed with further research.

Femoral insufficiency fractures associated with prolonged bisphosphonate therapy

BACKGROUND

Emerging evidence has linked the long-term use of bisphosphonates with femoral insufficiency fractures. It has been suggested that the prolonged effect on bone remodeling leads to the accumulation of microfractures and weakening of bone.

QUESTIONS/PURPOSES

We investigated the association between bisphosphonate use and femoral insufficiency fractures.

METHODS

We evaluated 100 patients with low-energy femoral shaft fractures before and after bisphosphonates became available for use. Twenty-one consecutive patients who presented between January 1995 and February 1997 were compared with 79 consecutive patients who presented between January 2007 and February 2009. The radiographs of all 100 patients were examined for evidence of preexisting insufficiency fractures. We identified insufficiency fractures by a transverse fracture line on the tension side of the femur with lateral cortical thickening immediately adjacent to the fracture. Relevant details from the history were recorded.

RESULTS

Forty-one patients had an underlying femoral insufficiency fracture, all of whom had been receiving bisphosphonate therapy. Among the 21 patients with low-energy femoral fractures before the availability of bisphosphonates, none had insufficiency fractures. Of the 41 patients with insufficiency fractures, 29 (71%) had prodromal pain and 18 (44%) had bilateral insufficiency fractures. Bisphosphonate use was associated (odds ratio greater than 1000) with insufficiency fracture. The mean duration of bisphosphonate use in patients with insufficiency fractures was longer than in patients without fractures (7.1 versus 3.2 years).

CONCLUSION

Long-term bisphosphonate use is associated with insufficiency fractures of the femoral shaft, which commonly present with prodromal thigh pain and may be bilateral. These fractures were not seen before bisphosphonates became available for use.

Progress in osteoporosis and fracture prevention: focus on postmenopausal women

In the past decade, we have witnessed a revolution in osteoporosis diagnosis and therapeutics. This includes enhanced understanding of basic bone biology, recognizing the severe consequences of fractures in terms of morbidity and short-term re-fracture and mortality risk and case finding based on clinical risks, bone mineral density, new imaging approaches, and contributors to secondary osteoporosis. Medical interventions that reduce fracture risk include sufficient calcium and vitamin D together with a wide spectrum of drug therapies (with antiresorptive, anabolic, or mixed effects). Emerging therapeutic options that target molecules of bone metabolism indicate that the next decade should offer even greater promise for further improving our diagnostic and treatment approaches.

Association of low-energy femoral fractures with prolonged bisphosphonate use: a case control study

SUMMARY

Recent evidence has linked long-term bisphosphonate use with insufficiency fractures of the femur in postmenopausal women. In this case-control study, we have identified a significant association between a unique fracture of the femoral shaft, a transverse fracture in an area of thickened cortices, and long-term bisphosphonate use. Further studies are warranted.

INTRODUCTION

Although clinical trials confirm the anti-fracture efficacy of bisphosphonates over 3-5 years, the long-term effects of bisphosphonate use on bone metabolism are unknown. Femoral insufficiency fractures in patients on prolonged treatment have been reported.

METHODS

We performed a retrospective case-control study of postmenopausal women who presented with low-energy femoral fractures from 2000 to 2007. Forty-one subtrochanteric and femoral shaft fracture cases were identified and matched by age, race, and body mass index to one intertrochanteric and femoral neck fracture each.

RESULTS

Bisphosphonate use was observed in 15 of the 41 subtrochanteric/shaft cases, compared to nine of the 82 intertrochanteric/femoral neck controls (Mantel-Haenszel odds ratio (OR), 4.44 [95% confidence interval (CI) 1.77-11.35]; P = 0.002). A common X-ray pattern was identified in ten of the 15 subtrochanteric/shaft cases on a bisphosphonate. This X-ray pattern was highly associated with bisphosphonate use (OR, 15.33 [95% CI 3.06-76.90]; P < 0.001). Duration of bisphosphonate use was longer in subtrochanteric/shaft cases compared to both hip fracture controls groups (P = 0.001).

CONCLUSIONS

We found a significantly greater proportion of patients with subtrochanteric/shaft fractures to be on long-term bisphosphonates than intertrochanteric/femoral neck fractures. Bisphosphonate use was highly associated with a unique X-ray pattern. Further studies are warranted.

Hormesis and medicine

Evidence is presented which supports the conclusion that the hormetic dose-response model is the most common and fundamental in the biological and biomedical sciences, being highly generalizable across biological model, endpoint measured and chemical class and physical agent. The paper provides a broad spectrum of applications of the hormesis concept for clinical medicine including anxiety, seizure, memory, stroke, cancer chemotherapy, dermatological processes such as hair growth, osteoporosis, ocular diseases, including retinal detachment, statin effects on cardiovascular function and tumour development, benign prostate enlargement, male sexual behaviours/dysfunctions, and prion diseases.

Considerations for development of surrogate endpoints for antifracture efficacy of new treatments in osteoporosis: a perspective

Because of the broad availability of efficacious osteoporosis therapies, conduct of placebo-controlled trials in subjects at high risk for fracture is becoming increasing difficult. Alternative trial designs include placebo-controlled trials in patients at low risk for fracture or active comparator studies, both of which would require enormous sample sizes and associated financial resources. Another more attractive alternative is to develop and validate surrogate endpoints for fracture. In this perspective, we review the concept of surrogate endpoints as it has been developed in other fields of medicine and discuss how it could be applied in clinical trials of osteoporosis. We outline a stepwise approach and possible study designs to qualify a biomarker as a surrogate endpoint in osteoporosis and review the existing data for several potential surrogate endpoints to assess their success in meeting the proposed criteria. Finally, we suggest a research agenda needed to advance the development of biomarkers as surrogate endpoints for fracture in osteoporosis trials. To ensure optimal development and best use of biomarkers to accelerate drug development, continuous dialog among the health professionals, industry, and regulators is of paramount importance.

Alendronate for the primary and secondary prevention of osteoporotic fractures in postmenopausal women

BACKGROUND

Osteoporosis is an abnormal reduction in bone mass and bone deterioration leading to increased fracture risk. Alendronate belongs to the bisphosphonate class of drugs, which act to inhibit bone resorption by interfering with the activity of osteoclasts.

OBJECTIVES

To assess the efficacy of alendronate in the primary and secondary prevention of osteoporotic fractures in postmenopausal women.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE and EMBASE for relevant randomized controlled trials published between 1966 to 2007.

SELECTION CRITERIA

Women receiving at least one year of alendronate, for postmenopausal osteoporosis, were compared to those receiving placebo and/or concurrent calcium/vitamin D. The outcome was fracture incidence.

DATA COLLECTION AND ANALYSIS

We undertook study selection and data abstraction in duplicate. We performed meta-analysis of fracture outcomes using relative risks and a > 15% relative change was considered clinically important. We assessed study quality through reporting of allocation concealment, blinding and withdrawals.

MAIN RESULTS

Eleven trials representing 12,068 women were included in the review. Relative (RRR) and absolute (ARR) risk reductions for the 10 mg dose were as follows. For vertebral fractures, a significant 45% RRR was found (RR 0.55, 95% CI 0.45 to 0.67). This was significant for both primary prevention, with 45% RRR (RR 0.55, 95% CI 0.38 to 0.80) and 2% ARR, and secondary prevention with 45% RRR (RR 0.55, 95% CI 0.43 to 0.69) and 6% ARR. For non-vertebral fractures, a significant 16% RRR was found (RR 0.84, 95% CI 0.74 to 0.94). This was significant for secondary prevention, with 23% RRR (RR 0.77, 95% CI 0.64 to 0.92) and 2% ARR, but not for primary prevention (RR 0.89, 95% CI 0.76 to 1.04). There was a significant 40% RRR in hip fractures (RR 0.60, 95% CI 0.40 to 0.92), but only secondary prevention was significant with 53% RRR (RR 0.47, 95% CI 0.26 to 0.85) and 1% ARR. The only significance found for wrist was in secondary prevention, with a 50% RRR (RR 0.50 95% CI 0.34 to 0.73) and 2% ARR. For adverse events, we found no statistically significant differences in any included study. However, observational data raise concerns regarding potential risk for upper gastrointestinal injury and, less commonly, osteonecrosis of the jaw.

AUTHORS' CONCLUSIONS

At 10 mg per day, both clinically important and statistically significant reductions in vertebral, non-vertebral, hip and wrist fractures were observed for secondary prevention ('gold' level evidence, www.cochranemsk.org). We found no statistically significant results for primary prevention, with the exception of vertebral fractures, for which the reduction was clinically important ('gold' level evidence).

Inhibitory Effect of Alendronate on Bone Resorption of Autogenous Free Bone Grafts in Rats

PURPOSE

This study was designed to investigate the effect of alendronate on the resorption of autogenous free bone grafts by biochemical and histopathologic methods. Alendronate is a potent inhibitor of osteoclast-mediated bone resorption with no adverse effect on the mineralization of bone.

MATERIALS AND METHODS

In this experimental study, 56 male Wistar rats were used. Autogenous free bone grafts were prepared with standard trephine bur in the right femur of each rat. The animals were then divided into 2 groups. In the first group, rats were treated with a daily subcutaneous injection of alendronate (0.25 mg/kg/day) for 2, 4, and 12 weeks, respectively. In the second group, rats were treated with saline solution injection for the same time periods. At the end of these periods, serum and overnight fasting urine samples were collected from all animals. In serum, the level of calcium, phosphate, parathyroid hormone, and 25 dihydroxyvitamin D were measured. In urine, pyridinoline, deoxypyridinoline, calcium, and creatinine were analyzed. The rats were sacrificed at 2, 4, and 12 weeks postsurgery. The number of osteoclasts and the number and size of resorptive lacunae were evaluated histopathologically.

RESULTS

Alendronate caused significant reduction in urinary pyridinoline, deoxypyridinoline levels biochemically, and the number of osteoclasts and resorptive lacunae histopathologically.

CONCLUSION

Suppression of the graft resorption occurred in the alendronate-treated group.

Sustained beneficial effect of intravenous bisphosphonates after their discontinuation in children

We studied if the beneficial effects of bisphosphonates are maintained after their discontinuation, and whether adverse effects may develop. Seventeen children in whom I.V. bisphosphonates were discontinued for at least 12 months were included. Fracture rate (FR), skeletal pain, bone mineral density of total body (TB) and spine L(2-4), skeletal radiographs, bone markers and kidney functions were compared between: (a) before treatment, (b) end of treatment, and (c) last follow-up. Mean treatment duration was 22+/-2 months (6-43) and follow-up 26+/-2 months (18-44). FR (mean +/- SD) decreased from 0.74+/-0.21/year before treatment to 0.35+/-0.11/year after treatment and 0.20+/-0.09/year at follow-up (p<0.05). Three children had bone pain before treatment, six during treatment and none at end of follow-up (p<0.05). TB Z-score increased from -1.24+/-0.50 at baseline to -0.37+/-0.44 at end of treatment and -0.39+/-0.37 at follow-up (p<0.05). Spinal Z-score increased from -1.65+/-0.57 to -0.34+/-0.56 and 0.19+/-0.49, respectively (p<0.05). Bone turnover markers showed sustained effect of bisphosphonates. No adverse effects on kidney functions or skeletal radiographs were noted. We conclude that I.V. bisphosphonates continue to exert their beneficial effect for a mean of 26+/-2 months after their discontinuation; therefore, once therapeutic goals are achieved, the medication can be withheld, followed by periodic re-evaluation.

Effect of alendronate on bone mineral density in spinal cord injury patients: a pilot study

STUDY DESIGN

Prospective, randomised controlled trial.

OBJECTIVE

To evaluate the effect of alendronate on bone mineral density in chronic spinal cord injury (SCI) patients.

SETTING

University-based rehabilitation centre in São Paulo, Brazil.

METHODS

A total of 19 chronic SCI patients were evaluated, divided into a control group and an experimental group. Control group patients received 1000 mg of calcium daily, and experimental group patients received 1000 mg of calcium plus 10 mg of alendronate daily. The study duration was 6 months. In all, 12 densitometric parameters were analysed using whole-body dual-energy X-ray absorptiometry at baseline and after 6 months.

RESULTS

The experimental group presented increases in nine densitometric parameters, although statistical significance was attained in only two of those parameters. In the control group, an increase was observed in only one parameter, whereas the remaining 11 presented either no alteration or a decrease.

CONCLUSION

The use of alendronate had a positive effect on bone mineral density in SCI patients and therefore represents a potential tool for prevention and treatment of osteoporosis in this population.

Alendronate Therapy May Be Effective in the Prevention of Bone Loss Around Titanium Implants Inserted in Estrogen-Deficient Rats

BACKGROUND

This study evaluated whether alendronate (ALD) influences bone healing around titanium implants inserted in ovariectomized rats and whether it provides a residual effect after its withdrawal.

METHODS

Bilateral ovariectomies were performed in 87 Wistar rats and one screw-shaped titanium implant was placed in the tibiae. The animals were divided into the following groups: group SHAM (N = 15): sham surgeries; group OVX (N = 15): ovariectomy; group AT (N = 15): OVX plus alendronate administration for 80 days; group AW (N = 14): OVX plus alendronate administration for 40 days; group ET (N = 14): OVX plus 17beta estradiol administration for 80 days; or group EW (N = 14): OVX plus 17beta estradiol administration for 40 days. Bone-to-implant contact (BIC), bone area (BA) within the limits of implant threads, and bone density in a 500 microm-wide zone lateral to the implant (BD) were obtained and measured for the cortical (zone A) and cancellous (zone B) regions.

RESULTS

In zone A, data analysis showed no significant differences among the groups regarding BIC and BD (P >0.05), and a slight beneficial effect of estradiol on BA when compared with the OVX, EW, and AW groups (P <0.05). In zone B, OVX negatively impacted bone healing around the implants, resulting in reduced BA and BD (P<0.05). ALD (continuous/interrupted) and estradiol (only continuous) positively affected BIC, BA, and BD, resulting in values at the same level as the control group (SHAM).

CONCLUSIONS

ALD may prevent the negative influence of estrogen deficiency on bone healing around titanium implants inserted in OVX rats. This positive effect, in contrast to estradiol, is sustained following its withdrawal.

Rat model of the hypercalcaemia induced by parathyroid hormone-related protein: characteristics of three bisphosphonates

In our preliminary experiment, we found that a constant infusion of a high dose of parathyroid hormone-related protein induced both hyperphosphataemia and hypocalcaemia, secondary to renal dysfunction. Therefore, in this study, we developed two types of parathyroid hormone-related protein-induced hypercalcaemia models. One is the hypercalcaemia model, which did not show renal-dysfunction-induced hypocalcaemia. This model might be suitable for estimating hypocalcaemic activities of drugs, especially of those that act on bone resorption. The other is the model for estimating histological changes, which is associated with renal dysfunction. We then used these models to investigate the effects of three different bisphosphonates. Since the hypercalcaemic effect of parathyroid hormone-related protein infusion plateaued at 20 pmol/h, and higher doses of parathyroid hormone-related protein caused an elevation of blood urea nitrogen, the parathyroid hormone-related protein infusion rate was fixed at 20 pmol/h to avoid renal dysfunction and at 40 pmol/h to elicit renal dysfunction. The hypocalcaemic efficiencies of clodronate and etidronate were almost the same but pamidronate was 17.9 times more potent than clodronate. Additionally, both clodronate and pamidronate decreased the plasma concentrations of blood urea nitrogen and the Ca2+ times inorganic P product, whereas etidronate lacked these effects. Clodronate suppressed renal calcification and tubular dilatation in the renal-dysfunction model. These data indicated that clodronate and pamidronate not only decrease the plasma Ca2+ concentration but also improve the renal dysfunction induced by hypercalcaemia.

Alendronate May Protect Against Increased Periodontitis-Related Bone Loss in Estrogen-Deficient Rats

BACKGROUND

The aim of this study was to evaluate the impact of alendronate (ALD) and estrogen (EST) therapies and their withdrawal on bone loss in experimental periodontitis in ovariectomized rats.

METHODS

Eighty-seven Wistar rats were divided into six groups: group 1 (N = 15): sham surgery; group 2 (N = 15): ovariectomy (OVX); group 3 (N = 15): OVX plus alendronate administration for 80 days (AT); group 4 (N = 14): OVX plus alendronate administration for 40 days (AW); group 5 (N = 14): OVX plus 17beta estradiol administration for 80 days (ET); and group 6 (N = 14): OVX plus 17beta estradiol administration for 40 days (EW). Twenty-one days after ovariectomy or sham surgery, one mandibular molar was randomly assigned to receive a ligature, while the contralateral tooth was left unligated. Sixty days later, the animals were sacrificed and the specimens processed.

RESULTS

OVX presented a direct impact on alveolar bone, regardless of plaque accumulation and significantly increased bone loss resulting from periodontitis (P < 0.05). The effect of OVX on unligated sites was significantly reduced by AT, AW, and ET (P < 0.05), but not by EW (P > 0.05). In addition, alendronate administration (AT/AW) significantly reduced the impact of OVX on periodontitis-related bone loss (P < 0.05), while estradiol did not (P > 0.05).

CONCLUSION

Within the limits of this study, alendronate administration, but not estrogen replacement, may protect against the impact of estrogen deficiency on alveolar bone presenting a significant residual effect after its withdrawal.

The effects of three-month intravenous ibandronate on bone mineral density and bone remodeling in Klinefelter's syndrome: the influence of vitamin D deficiency and hormonal status

The aim of this study was to evaluate the effects of a 2-year treatment with intravenous ibandronate (2 mg every 3 months) and calcium (1000 mg daily) on bone mineral density (BMD) and bone markers in 14 patients with Klinefelter's syndrome who served as their own controls. During the follow-up of 5.9 years before the treatment was started, the mean rates of bone loss per year were 1.3, 0.9, and 0.6% in the lumbar spine, femoral neck, and total body, respectively. The rate of bone loss from the spine was significantly inversely related to both serum estradiol and testosterone. At the onset of treatment, the average age of the patients was 55.2 years (48-64 years), and T score, mean +/- SD, at the lumbar spine was -2.6 +/- 1.0. After 6 months, the mean serum CTX and PINP decreased by 39 and 55% below the pretreatment concentrations, respectively (P < 0.05). After 12 months of treatment, the patients gained mean +/- SD, 7.8 +/- 2.3% of BMD in the lumbar spine, 3.8 +/- 4.0% in the femoral neck, and 4.7 +/- 2.2% in the total body (P < 0.05). During the second year of treatment, all patients also received 700 IU of vitamin D daily. After 24 months of treatment, the patients gained 10.1 +/- 4.3% of BMD in the lumbar spine, 6.7 +/- 5.5% in the femoral neck, and 5.5 +/- 2.5% in the total body. The increase in BMD in the second year of ibandronate treatment was not significant. The rate of gain of BMD in the femoral neck was positively related to serum concentrations of testosterone and inversely related to 25-hydroxyvitamin D (P < 0.005). After the discontinuation of treatment, serum CTX and PINP increased to the pretreatment levels, and the lumbar spine and femur neck BMD decreased (P < 0.05). In conclusion, ibandronate was effective in increasing BMD at all sites, but the effects were adversely influenced by vitamin D insufficiency or deficiency. The overall changes in biochemical markers of bone remodeling were consistent with the antiresorptive effect of the drug.

Intravenous intermittent neridronate in the treatment of postmenopausal osteoporosis

Bisphosphonates have been used with success in the treatment of osteoporosis, but oral therapy often lacks compliance. Here we report the results of clinical trial with aminobisphosphonate neridronate administered intravenously (i.v.). The study included 78 postmenopausal women with spine bone mineral density (BMD) at least -2.5 SD below peak. Patients were randomized to receive for 2 years either 50 mg i.v. neridronate bimonthly and 500 mg calcium plus 400 U vitamin D supplements daily (n=39) or calcium-vitamin D supplements alone (control group, n=39). Treatment was continued over 2 years with an additional 1 year follow-up of calcium-vitamin D supplements alone. Neridronate was well tolerated with the appearance of typical clinical signs of an acute phase reaction in only 3 of the patients after the first infusion. In the control group no significant changes in BMD or bone markers were observed. In the neridronate group BMD rose progressively at the spine rose up to 7.4% +/- 6.1% (SD) and at the femoral neck up to 5.8% +/- 8.2% (SD) at the end of the second year. In the succeeding follow-up these gains were maintained at both skeletal sites. Serum bone alkaline phosphatase (bone ALP) and serum type I collagen C-telopeptide (s-CTX) significantly decreased within 2 months. The bone ALP values reached a -35% plateau after 6 months, while s-CTX attained the lowest mean value (-47%) only by the end of the treatment with neridronate. Both bone markers returned almost to baseline values 1 year after treatment discontinuation. Treatment of postmenopausal osteoporosis with 50 mg i.v. neridronate bimonthly results in clinically relevant increases in BMD, among the largest so far observed with any other bisphosphonate.

Effect of alendronate and exercise on bone and physical performance of postmenopausal women: a randomized controlled trial

In this randomized, double-blind, placebo-controlled 12-month trial we evaluated effects of weight- bearing jumping exercise and oral alendronate, alone or in combination, on the mass and structure of bone, risk factors for falling (muscle strength and power, postural sway, and dynamic balance), and cardiorespiratory fitness in postmenopausal women. A total of 164 healthy, sedentary, early postmenopausal women were randomly assigned to one of four experimental groups: (1) 5 mg of alendronate daily plus progressive jumping exercise, (2) 5 mg alendronate, (3) placebo plus progressive jumping exercise, or (4) placebo. The primary endpoint was 12-month change in bone mass and geometry (measured with dual-energy X-ray absorptiometry and peripheral computed tomography at several axial and limb sites) and physical performance; the secondary endpoint was change in biochemical markers of bone turnover. The jumping exercise was conducted an average 1.6 +/- 0.9 (mean +/- SD) times a week. Alendronate daily was effective in increasing bone mass at the lumbar spine (alendronate vs placebo 3.5%; 95% CI, 2.2-4.9%) and femoral neck (1.3%; 95% CI, 0.2-2.4%) but did not affect other bone sites. Exercise alone had no effect on bone mass at the lumbar spine or femoral neck; it had neither an additive nor an interactive effect with alendronate at these bone sites. However, at the distal tibia the mean increase of 3.6% (0.3-7.1%) in the section modulus (that is, bone strength) and 3.7% (0.1-7.3%) increase in the ratio of cortical bone to total bone area were statistically significant in the exercise group compared to the nonexercise group, indicating exercise-induced thickening of the bone cortex. Bone turnover was reduced in alendronate groups only. Alendronate had no effect on physical performance while the jumping exercise improved leg extensor power, dynamic balance, and cardiorespiratory fitness. As conclusion Alendronate is effective in increasing bone mass at the lumbar spine and femoral neck, while exercise is effective in increasing the mechanical properties of bone at some of the most loaded bone sites, as well as improving the participants' muscular performance and dynamic balance. Together alendronate and exercise may effectively decrease the risk of osteoporotic fractures.

Comparison of change in bone resorption and bone mineral density with once-weekly alendronate and daily risedronate: a randomised, placebo-controlled study

OBJECTIVE

To compare the effects of alendronate (ALN) 70 mg once weekly (OW) and risedronate (RIS) 5 mg daily between-meal dosing on biochemical markers of bone turnover and bone mineral density (BMD) in postmenopausal women with osteoporosis.

RESEARCH DESIGN AND METHODS

This was a 3-month, randomised, double-blind, placebo-controlled study with a double-blind extension to 12 months. The study enrolled 549 postmenopausal women (ALN 219, RIS 222 and placebo (PBO) 108) who were > or =60 years of age at outpatient centres.

MAIN OUTCOME MEASURES

The primary endpoint was reduction in urine N-telopeptides of type 1 collagen (NTx) corrected for creatinine level at 3 months. Secondary parameters included change in BMD at the spine and hip at 6 and 12 months, NTx at 1, 6 and 12 months, and serum bone-specific alkaline phosphatase (BSAP) at 1, 3, 6 and 12 months. Adverse experiences (AEs) were recorded throughout the study for an assessment of treatment safety profiles and tolerability.

RESULTS

Over 3 months, ALN produced a significantly greater mean reduction in urine NTx than did RIS (-52% vs -32%, p < 0.001), which was maintained at 12 months. ALN produced a significantly greater mean BMD increase than did RIS at 6 months, and it was maintained at 12 months at the lumbar spine (4.8% vs 2.8%, p < 0.001) and total hip (2.7% vs 0.9%, p < 0.001), as well as at the trochanter and femoral neck. Significant reductions in BSAP with ALN compared to RIS were maintained over the 12 months of treatment. Study size did not allow for meaningful assessment of differences in fracture rates. Tolerability was generally similar between ALN, RIS and PBO, and the incidence of upper GI AEs causing discontinuation and oesophageal AEs was similar in the ALN and RIS groups.

CONCLUSION

In this study, ALN 70 mg OW produced a 50% greater reduction in bone resorption as measured by urine NTx and significantly greater increases in lumbar spine and hip BMD than did RIS 5 mg daily. The treatments had similar safety profiles and were generally well-tolerated. Additional studies are needed comparing OW ALN with OW RIS, which became available after the commencement of the present study.

Treatment of osteoporosis: current status and recent advances

With the advent of new treatment choices, osteoporosis should no longer be considered an inevitable part of aging but rather a disease that can be treated. This article provides an overview of recent advances in treatment of osteoporosis.

Meta-analyses of therapies for postmenopausal osteoporosis. II. Meta-analysis of alendronate for the treatment of postmenopausal women

OBJECTIVE

To review the effect of alendronate on bone density and fractures in postmenopausal women.

DATA SOURCE

We searched MEDLINE, EMBASE, Current Contents, and the Cochrane Controlled trials registry from 1980 to 1999, and we examined citations of relevant articles and proceedings of international meetings.

STUDY SELECTION

We included 11 trials that randomized women to alendronate or placebo and measured bone density for at least 1 yr.

DATA EXTRACTION

For each trial, three independent reviewers assessed the methodological quality and abstracted data.

DATA SYNTHESIS

The pooled relative risk (RR) for vertebral fractures in patients given 5 mg or more of alendronate was 0.52 [95% confidence interval (CI), 0.43-0.65]. The RR of nonvertebral fractures in patients given 10 mg or more of alendronate was 0.51 (95% CI 0.38-0.69), an appreciably greater effect than for the 5 mg dose. We found a similar reduction in RR across nonvertebral fracture types; in particular, RR reductions for fractures traditionally thought to be "osteoporotic," such as hip and forearm, were very similar to RR reductions for "nonosteoporotic" fractures. Individual studies showed similar results, reflected in the P values of the test of heterogeneity (P = 0.99 for vertebral and 0.88 for nonvertebral fractures). Alendronate produced positive effects on the percentage change in bone density, which increased with both dose and time. After 3 yr of treatment with 10 mg of alendronate or more, the pooled estimate of the difference in percentage change between alendronate and placebo was 7.48% (95% CI 6.12-8.85) for the lumbar spine (2-3 yr), 5.60% (95% CI 4.80-6.39) for the hip (3-4 yr), 2.08% (95% CI 1.53-2.63) for the forearm (2-4 yr), and 2.73% (95% CI 2.27-3.20) for the total body (3 yr). Heterogeneity of the treatment effect of alendronate was not consistently explained by any of our a priori hypotheses; in particular, the effect was very similar in prevention and treatment studies. The pooled RR for discontinuing medication due to adverse effects for 5 mg or greater of alendronate was 1.15 (95% CI 0.93-1.42). The pooled RR for discontinuing medication due to gastro-intestinal (GI) side effects for 5 mg or greater was 1.03 (0.81-1.30, P = 0.83), and the pooled RR for GI adverse effects with continuation of medication was 1.03 (0.98 to 1.07) P = 0.23.

CONCLUSIONS

Alendronate increases bone density in both early postmenopausal women and those with established osteoporosis while reducing the rate of vertebral fracture over 2-3 yr of treatment. Reductions in nonvertebral fractures are evident among postmenopausal women without prevalent fractures and have bone mineral density (BMD) levels below the World Health Organization threshold for osteoporosis. The impact on fractures appears consistent across all fracture types, casting doubt on traditional distinctions between osteoporotic and nonosteoporotic fractures.

The underuse of therapy in the secondary prevention of hip fractures

There is strong evidence to indicate that individuals who sustain a hip fracture are at a greater risk of developing another. The management of such patients should include efforts to prevent future fractures, including prescribing medications that have been shown to lower hip fracture risk. Such therapies that are currently available include calcium and vitamin D supplementation, alendronic acid and risedronic acid. In addition, there is epidemiological evidence to indicate that estrogen may also decrease the risk of hip fracture. Parathyroid hormone is another agent that has shown promise in this regard and is likely to be available for clinical use in the near future. However, the rates of utilisation of these therapies among patients with hip fractures are low. It is important to emphasise that secondary prevention of hip fractures should be an integral part of the management of individuals who sustain hip fractures.

Osteoporosis in children and adolescent girls: case report of idiopathic juvenile osteoporosis and review of the literature

The diagnosis and treatment of osteoporosis is an important aspect of gynecologic training and practice. Idiopathic juvenile osteoporosis (IJO) is a rare disease of children and adolescents that resolves after the onset of puberty. A case report is presented and current methods of diagnosis and treatment of IJO are discussed as well as the differential diagnosis. A MEDLINE search was performed of the following terms: idiopathic juvenile osteoporosis, pediatric osteoporosis, adolescent osteoporosis, bisphosphonates pediatric adolescent, and pregnancy osteoporosis, and references from bibliographies of selected papers were used as well. All papers in English, French, and German are considered in this review. There were 114 papers selected as relevant to the topic. Data relevant to the diagnosis, pathogenesis, methods of imaging, laboratory evaluation, differential diagnosis, and treatment of IJO are presented. IJO is a diagnosis of exclusion in the pediatric and adolescent patient with osteoporosis. Although bone density gradually improves after the onset of puberty, treatment of currently affected children and adolescents involves activity restriction, calcium, vitamin D, and bisphosphonate therapy. Future reproductive concerns are discussed and areas requiring additional study are reviewed.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After completion of this article, the reader will be able to describe the condition idiopathic juvenile osteoporosis, compare the clinical features of this condition to other similar conditions, outline the diagnostic workup of a child with this condition, and list the potential therapeutic options for a patient with idiopathic juvenile osteoporosis.

Positive effect of etidronate therapy is maintained after drug is terminated in patients using corticosteroids

Following a 52-wk randomized controlled trial of intermittent cyclic etidronate therapy in patients using corticosteroids, we performed a 52-wk open-label trial of calcium alone in 114 corticosteroid-treated patients to determine whether the beneficial effect of etidronate is maintained after the drug is discontinued. All patients were given 500 mg/d of elemental calcium. Sixty-one and 53 patients made up the former placebo and etidronate groups, respectively. A total of 89 (98%) of patients in the former placebo and etidronate groups remained on corticosteroids throughout the second year. The mean (SE) percentage change in bone mineral density of the lumbar spine, femoral neck, and trochanter were compared between groups. The difference between groups in mean percentage change from baseline (wk 0, initiation of etidronate or placebo therapy) in the bone density of the lumbar spine, femoral neck, and trochanter, following 104 wk, was 3.8 (0.9), 3.0 (1.1), and 4.3 (1.1), respectively (p < 0.05, all sites), in favor of the former etidronate group. While not significant, the former placebo group demonstrated a slightly larger rate of decline in bone density over the second year than the former etidronate group at all three sites. Following the discontinuation of etidronate therapy, there was no accelerated bone loss and there was evidence of a residual protective effect in both the lumbar spine and femoral neck for up to 1 yr posttreatment.

Effects of alendronate on osteopenic postmenopausal Chinese women

To evaluate the effects of alendronate on postmenopausal Chinese women with osteopenia, we treated 46 subjects daily with either 10 mg alendronate (N = 24) or placebo plus 500 mg calcium supplement (N = 22), and measured their bone mineral density (BMD) at the lumbar spine and hip, and urinary bone resorption markers before, during, and after the 1 year treatment period. The bone markers included N-telopeptide of type I collagen (NTx) and deoxypyridinoline (Dpd); both were corrected by the concentration of creatinine in the same sample (NTx/Cr and Dpd/Cr). Both NTx/Cr and Dpd/Cr decreased significantly by 44% and 28%, respectively (p < 0.05 for both), in 1 month in the active treatment group but did not change in the placebo group. BMD at the spine, femoral neck, trochanter, and Ward's triangle increased significantly by 6 months and showed a further increase through month 12 at the spine in the alendronate-treated group. Relative to the placebo group, BMD changes at various sites in the alendronate-treated group were higher at 12 months by 6%-11%. Thus, our data suggest that 10 mg alendronate daily resulted in significant increases in spine and hip BMD, and decreases of urinary resorption markers in the osteopenic postmenopausal Chinese women studied. The amplitude of responses was higher than in previous reports in the USA and Europe.

Alendronate prevents bone loss in Chinese women with osteoporosis

The objectives of the Hong Kong study are to investigate the efficacy of 10 mg alendronate in preventing bone loss at the hip and spine in osteoporotic Chinese women. One hundred osteoporotic Chinese women, aged 60-79 years, were randomized to receive 10 mg of alendronate or placebo, with 500 mg elemental calcium. Bone mineral density (BMD) at the spine and hip were measured at baseline, 6 months, and 12 months. Seventy-eight subjects completed the study. The alendronate-treated group gained more bone at both the spine (p < 0.01) and femoral neck (p < 0.001), with a mean difference (+/-SE) of 2.4% (+/-0.86%) at the spine and 3.98% (+/-0.95%) at the femoral neck. Of the 100 patients, 6 subjects in the alendronate group and 5 subjects in the placebo group had mild gastrointestinal symptoms. We conclude that alendronate (10 mg) was effective in preventing bone loss in postmenopausal osteoporotic Chinese women.

Administration routes and delivery systems of bisphosphonates for the treatment of bone resorption

Geminal bisphosphonates (BPs) are a class of drugs considered to be stable analogs of pyrophosphate (P-O-P), a physiological regulator of calcification and bone resorption. A number of BPs have been approved for clinical use in Paget's disease, hypercalcemia of malignancy, and osteoporosis. The major disadvantage of the clinically utilized BPs is their poor oral absorption from the GI tract, typically less than 1% is absorbed. In addition, the BPs have been associated with adverse gastrointestinal effects in humans. The challenge for novel drug delivery systems is to achieve improved bioavailability and safety. In the first part of this review, we discuss the bioavailability of BPs, the effect of food on the absorption of BPs, the mechanism of BPs' absorption and the adverse gastrointestinal effects. In the second part of the review, various methods that have been used for improving the bioavailability of BPs are described. Dosage form strategies reviewed include the use of particular formulations for increasing oral absorption as well as decreasing adverse gastrointestinal effects, absorption enhancers, BP compounds and the solubility of their calcium complex/salts, and the prodrug approach. Because of the poor GI absorption, attempts have been made to enhance the bioavailability of BPs by several parenteral routes other than i.v. injections. Description of nasal administration, s.c. and i.m. injections, BP implants and targeted osteotropic delivery systems are reviewed.

Effects of two intermittent alendronate regimens in the prevention or treatment of postmenopausal osteoporosis

In clinical practice, a large proportion of patients have bone mass values for which a therapeutic intervention is considered necessary, but the accepted aim might be the sole preservation or marginal increases of the actual bone mass. These goals might be achieved with lower or intermittent doses of a powerful agent for the purpose of fewer side effects and improved compliance. The aim of this study was to assess the effects of two intermittent alendronate regimens in the treatment of postmenopausal osteoporosis. One hundred twenty-four postmenopausal women (age range 52-75 years, at least 7 years since last menopause) with a bone mineral density (BMD) at either the femoral neck or lumbar spine of 2 SD below the mean values of young healthy individuals, and without a history of previous osteoporotic fracture, were randomly assigned either to calcium/vitamin D supplements, alone or associated with two different intermittent oral alendronate regimens: 20 mg once a week (weekly alendronate group) or 10 mg daily (orally) for 1 month out of 3 (cyclical alendronate group). After 1 year, in both groups given intermittent alendronate, we observed significant increases in BMD at both the spine (+2.2 +/- 2.6 and +2.5 +/- 2.9) and femoral neck (+1.6 +/- 4.8 and +1.5 +/- 2.2) for the weekly and cyclical regimens, respectively. This was associated with a significant diminution of both serum bone-specific alkaline phosphatase and urinary N-telopeptides of collagen type I excretion. In the patients in the control group BMD decreased significantly at the lumbar spine, with a slight decline of serum bone-specific alkaline phosphatase. Compliance with treatment and drug tolerability were good in both alendronate groups. In conclusion, intermittent alendronate administration at cumulative doses (and costs) three times lower than those currently recommended for osteoporosis treatment is very well accepted, and is able to significantly increase BMD at the spine and femoral neck and to decrease the markers of bone turnover. These regimens can be clinically useful in the long-term treatment of postmenopausal osteoporosis without prevalent osteoporotic fractures, particularly in women with lower compliance for continuous administration.

Intermittent versus continuous clodronate administration in postmenopausal women with low bone mass

The aim of the study was to compare the effects on bone mass and turnover of continuous vs. intermittent clodronate administration on 120 postmenopausal women (average age 61 years) with low bone mass (femoral neck bone mineral density [BMD] of at least -1 SD or more, T-score), with another 30 women as a control group. Participants were given 1800 mg of clodronate every 6 months over 2 years using different treatment patterns: a) two continuous regimens, consisting of a daily oral dose of 400 mg or 100 mg every 10 days by intramuscular injection, the latter being considered continuous because the interval between injections is shorter than the time employed by each bone remodelling unit to complete the resorption phase of a remodelling cycle; and b) two intermittent regimens, consisting of 1800 mg every 6 months administered either as a single 18-h intravenous infusion or by separate infusions of 300 mg over 6 consecutive days. All women, including those in the control group, received calcium and vitamin D supplementation. After 2 years, continuous clodronate regimens caused an increase in BMD both at lumbar spine and proximal femur (L(1-4) BMD = 3.07% and 2.69%; femoral neck = 2.12% and 2.09%, respectively, with intramuscular and oral regimens). Intermittent clodronate administration was associated with a small increase or a stabilization in bone mass (L(1-4) BMD = 0.53% and 1.22%; femoral neck = 0.30% and 0.77%, respectively, with 1- and 6-day intravenous infusion regimens). From the 12th month, changes in spine and femoral neck BMD after continuous regimens were statistically different compared with that obtained with intermittent ones. Twenty-five of the 150 women (16.7%) discontinued the study before the end of the 2-year follow-up, but of these, only 7 dropped out because of adverse events related to the treatment itself. To summarize, intermittent clodronate administration could be a suitable option for the prevention of osteoporosis.

Bisphosphonates: from grandparents to grandchildren

Bisphosphonates are synthetic analogues of pyrophosphate that inhibit bone resorption by their action on osteoclasts. Bisphosphonates have been extensively used in the elderly with primary and secondary osteoporosis, Paget's disease, and hypercalcemia of malignancy. In recent years, bisphosphonates have been used to treat children acutely for resistant hypercalcemia and chronically for various metabolic bone diseases. The theoretical concerns of possible adverse effects of these drugs on the growing skeleton have not been proven to be true. In the present review, we have critically analyzed the available literature on bisphosphonate therapy in both adult and pediatric clinical trials. Although not yet approved by the FDA for use in children, bisphosphonates, from published experience, demonstrate benefit to the child with no serious adverse effects. Based on the literature analysis the review furnishes detailed recommendations and practical guidelines regarding the use of oral and intravenous bisphosphonates in children. Bisphosphonates might be the first agents to provide the pediatrician with an opportunity to treat mineral and bone disorders of childhood, which until recently did not have satisfactory therapy.

Intermittent and continuous administration of the bisphosphonate ibandronate in ovariohysterectomized beagle dogs: effects on bone morphometry and mineral properties

Bisphosphonates have emerged as a valuable treatment for postmenopausal osteoporosis. Bisphosphonate treatment is usually accompanied by a 3-6% gain in bone mineral density (BMD) during the first year of treatment and by a decrease in bone turnover. Despite low bone turnover, BMD continues to increase slowly beyond the first year of treatment. There is evidence that bisphosphonates not only increase bone volume but also enhance secondary mineralization. The present study was conducted to address this issue and to compare the effects of continuous and intermittent bisphosphonate therapy on static and dynamic parameters of bone structure, formation, and resorption and on mineral properties of bone. Sixty dogs were ovariohysterectomized (OHX) and 10 animals were sham-operated (Sham). Four months after surgery, OHX dogs were divided in six groups (n = 10 each). They received for 1 year ibandronate daily (5 out of 7 days) at a dose of 0, 0.8, 1.2, 4.1, and 14 microg/kg/day or intermittently (65 microg/kg/day, 2 weeks on, 11 weeks off). Sham dogs received vehicle daily. At month 4, there was a significant decrease in bone volume in OHX animals (p < 0.05). Doses of ibandronate >/= 4.1 microg/kg/day stopped or completely reversed bone loss. Bone turnover (activation frequency) was significantly depressed in OHX dogs given ibandronate at the dose of 14 microg/kg/day. This was accompanied by significantly higher crystal size, a higher mineral-to-matrix ratio, and a more uniformly mineralized bone matrix than in control dogs. This finding lends support to the hypothesis that an increase in secondary mineralization plays a role in gain in BMD associated with bisphosphonate treatment. Moreover, intermittent and continuous therapies had a similar effect on bone volume. However, intermittent therapy was more sparing on bone turnover and bone mineral properties. Intermittent therapy could therefore represent an attractive alternative approach to continuous therapy.

Monitoring alendronate therapy for osteoporosis

Alendronate is an antiresorptive therapy for osteoporosis and results in a decrease in bone turnover. To choose the optimal measurement for monitoring this therapy, the size of the change needs to be compared with the variability of the measurement. We studied 26 women with postmenopausal osteoporosis (bone mineral density [BMD] T score < -2.5), who were randomized in a 2:1 ratio to receive alendronate (10 mg/day) and calcium carbonate (500 mg/day) or calcium carbonate alone for 6 months. We measured serum markers of bone formation (osteocalcin [OC], bone isoform of alkaline phosphatase [BAP], and collagen type I C-terminal propeptide [CICP]) and urinary markers of bone resorption (cross-linked N-telopeptide [NTx], free deoxypyridinoline [iFDpd], and free pyridinolines). All subjects had two measurements 1 week apart at baseline to calculate the short-term variability. Biochemical measurements were then made at 4, 8, 12, 24, and 25 weeks. Measurements of bone mass were made by dual-energy X-ray absorptiometry (DXA) at the lumbar spine and proximal femur twice at baseline and then at 24 and 25 weeks. The mean difference in change in BMD and markers between both groups at the end of the study that were significant were (short-term variability in brackets): DXA total hip 4.3% (2.5%), NTX 49% (10%), iFDpd 22% (12%), OC 28% (13%), BAP 31% (13%), and CICP 31% (11%). Five of the six markers showed significant responses to alendronate therapy, but they differed in the relationship between size of response and variability. These biochemical markers performed better than DXA for monitoring alendronate therapy over 6 months.

Practical clinical application of biochemical markers of bone turnover: Consensus of an expert panel

Biochemical markers of bone turnover have emerged as powerful tools to aid in managing osteoporosis. The newer bone markers have been intensively studied for more than a decade. As a result, we can now confidently report their clinical utility in assessing risk of rapid bone loss and fracture, and monitoring therapy in postmenopausal women with or at risk of osteoporosis. In this review, we will provide a comprehensive foundation for this utility. While there are still questions remaining to be answered, bone marker technology has matured to play an essential role in patient management. We will describe, in practical terms, how bone markers can be appropriately incorporated into clinical practice today.

Early changes in biochemical markers of bone turnover predict the long-term response to alendronate therapy in representative elderly women: a randomized clinical trial

Although the antiresorptive agent alendronate has been shown to increase bone mineral density (BMD) at the hip and spine and decrease the incidence of osteoporotic fractures in older women, few data are available regarding early prediction of long-term response to therapy, particularly with regard to increases in hip BMD. Examining short-term changes in biochemical markers incorporates physiologic response with therapeutic compliance and should provide useful prognostic information for patients. The objective of this study was to examine whether early changes in biochemical markers of bone turnover predict long-term changes in hip BMD in elderly women. The study was a double-blind, placebo-controlled, randomized clinical trial which took place in a community-based academic hospital. One hundred and twenty community-dwelling, ambulatory women 65 years of age and older participated in the study. Intervention consisted of alendronate versus placebo for 2.5 years. All patients received appropriate calcium and vitamin D supplementation. The principal outcome measures included BMD of the hip (total hip, femoral neck, trochanter, and intertrochanter), spine (posteroanterior [PA] and lateral), total body, and radius. Biochemical markers of bone resorption included urinary N-telopeptide cross-linked collagen type I and free deoxypyridinoline; markers of bone formation included serum osteocalcin and bone-specific alkaline phosphatase. Long-term alendronate therapy was associated with increased BMD at the total hip (4.0%), femoral neck (3.1%), trochanter (5.5%), intertrochanter (3.8%), PA spine (7.8%), lateral spine (10.6%), total body (2.2%), and one-third distal radius (1.3%) in elderly women (all p < 0.01). In the placebo group, bone density increased 1.9-2.1% at the spine (p < 0.05) and remained stable at all other sites. At 6 months, there were significant decreases in all markers of bone turnover (-10% to -53%, p < 0.01) in women on alendronate. The changes in urinary cross-linked collagen at 6 months correlated with long-term bone density changes at the hip (r = -0.35, p < 0.01), trochanter (r = -0.36, p < 0.01), PA spine (r = -0.41, p < 0.01), and total body (r = -0.34, p < 0.05). At 6 months, patients with the greatest drop in urinary cross-linked collagen (65% or more) demonstrated the greatest gains in total hip, trochanteric, and vertebral bone density (all p < 0.05). A 30% decrease in urinary cross-linked collagen at 6 months predicted a bone density increase of 2.8-4.1% for the hip regions and 5.8-6.9% for the spine views at the 2.5-year time point (p < 0.05). There were no substantive associations between changes in biochemical markers and bone density in the placebo group. Alendronate therapy was associated with significant long-term gains in BMD at all clinically relevant sites, including the hip, in elderly women. Moreover, these improvements were associated with early decreases in biochemical markers of bone turnover. Early dynamic decreases in urinary cross-linked collagen can be used to monitor and predict long-term response to bisphosphonate therapy in elderly women. Future studies are needed to determine if early assessment improves long-term patient compliance or uncovers poor compliance, thereby aiding the physician in maximizing the benefits of therapy.

Bisphosphonates stimulate formation of osteoblast precursors and mineralized nodules in murine and human bone marrow cultures in vitro and promote early osteoblastogenesis in young and aged mice in vivo

Recent in vitro findings suggest that bisphosphonates, potent inhibitors of osteoclastic bone resorption, may also have a direct action on osteoblasts. The purpose of this study was to search for potential effects of etidronate and alendronate on the formation of early and late osteoblastic cell precursors by measuring the number of colony-forming units for fibroblasts (CFU-F) and colony-forming units for osteoblasts (CFU-OB) in murine and human bone marrow cultures. In murine marrow cultures, etidronate (10(-5) to 10(-9) mol/L) significantly stimulated the formation of CFU-F with a maximal effect at 10(-5) mol/L (mean increase over control values+/-SD: 106+/-17%;p < 0.001), whereas alendronate had a biphasic effect, being stimulatory at concentrations below 10(-7) mol/L (78+/-5%; p < 0.001), and inhibitory at higher doses. The formation of CFU-OB was also inhibited by both bisphosphonates at the highest concentrations (10(-5) mol/L and 10(-6) mol/L), but it was significantly stimulated at lower concentrations (from 10(-7) to 10(-9) mol/L for etidronate and 10(-7) to 10(-10) mol/I, for alendronate; p < 0.001). In human bone marrow cultures, alendronate (10(-8) to 10-(12) mol/L) increased CFU-F formation with a maximal effect at 10(-10) mol/L (161+/-12 %; p < 0.01). CFU-OB formation, observed only in the presence of dexamethasone (10(-8) mol/L), was markedly stimulated by alendronate at the above concentrations with a maximal increase at 10(-10) mol/L (133+/-34%; p < 0.001). The in vivo short-term effects of bisphosphonates on the formation of early osteoblast precursors were also studied in bone marrow cultures from young female mice treated with weekly subcutaneous injections of etidronate (0.3, 3, and 30 mg/kg) or alendronate (0.3, 3, and 30 microg/kg) and from aging female mice treated with the two lowest doses of both drugs. After 1 month of treatment, etidronate (0.3 and 3 mg/kg) and alendronate (0.3 and 3 microg/kg) significantly increased the number of CFU-F colonies in the bone marrow from young and old animals, whereas the highest dose of both drugs had no effect in young mice. Our results, together with previously reported observations of bone-forming effects in osteoporosis, suggest that bisphosphonates may have, in vivo, a potentially relevant influence on cells of the osteoblastic lineage, distinct from their inhibitory action on osteoclasts.

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

The study was a 1 year randomized, double-blind, placebo-controlled study of ibandronate treatment in postmenopausal, osteopenic women. Participants were followed for 1 year after withdrawal of treatment. All women were at least 10 years past menopause and had a baseline bone mineral density (BMD) at the distal forearm at least 1.5 standard deviations below the premenopausal mean peak value. A total of 141 women (78%) completed the first year, and 119 women (66%) the second year of the study. The dose-response data of the first year have been published previously (Ravn et al. Bone 19:527-533;1996). In this study, we analyzed the biochemical markers as predictors of response in bone mass during ibandronate treatment, and report withdrawal data from the last year of the study, when ibandronate was discontinued. The relative change in the biochemical markers was significantly correlated to the response in BMD. At 12 months, the r values ranged from -0.29 to -0.47 (p < 0.01) and were highest for CrossLaps (uCL) and osteocalcin (OC(N-MID)). The quartiles of women with the most reduced concentrations of uCL and OC(N-MID) during treatment showed a 360-430% higher response in BMD compared to quartiles with less reduced concentrations (p < 0.01). During the withdrawal period, uCL and alkaline phosphatase (AP) returned to baseline values 12 months after discontinuation of treatment in all groups, whereas OC(N-MID) and bone-specific AP were still reduced 10%-25% in the groups previously treated with the highest doses of ibandronate (1.0-5.0 mg) (p < 0.01). In the withdrawal period, BMD decreased equally in all groups (analysis of variance; not significant); with a linear rate of 2%/year on average (p < 0.05 to < 0.001) at the spine and femur. In conclusion, uCL and OC(N-MID) can be used to predict the response in bone mass during ibandronate treatment. The bone loss that resumes after withdrawal of ibandronate treatment is of a magnitude similar to that of normal postmenopausal bone loss.

Effect of alendronate on cultured normal human osteoblasts

Alendronate is an aminobisphosphonate with a potent anti-reabsorptive action that does not appear to interfere with bone mineralization, and is even able to increase bone mineral density in osteoporotic postmenopausal women through a still not fully understood mechanism. This study was conducted to assess the direct effect of alendronate on diverse aspects of normal human osteoblast physiology. For that purpose, the in vitro effect of a wide range of concentrations [from 10(-1) to 10(-12) mol/L] of alendronate on cell viability, proliferation, collagen synthesis, and the mineral-depositing capacity of normal human osteoblasts was tested. Alendronate effects were examined at 48 and 96 h of culture in the presence or absence of fetal calf serum. In vitro alendronate affected osteoblast viability at concentrations equal to or higher than 10(-4) mol/L. At concentrations equal to or higher than 10(-3) mol/L, no viable cells were observed in cultures. In vitro alendronate at concentrations between 10(-5) and 10(-12) mol/L did not have any effect on the proliferative capacity of normal human osteoblasts determined by two different techniques: (1) tritiated thymidine incorporation to DNA and (2) cell counting. Collagen synthesis by normal human osteoblasts showed a tendency to decrease following incubation with alendronate supplemented with fetal calf serum. This decrease was only statistically significant after 96 h of culture; however, a dose-response effect could not be documented. Finally, no effect of alendronate was observed on calcium deposition in vitro by normal human osteoblasts at concentrations equal to or lower than 10(-5) mol/L. In conclusion, the present study shows that alendronate in vitro does not affect viability, proliferation, and mineral deposit capacity of normal human osteoblasts at the concentration at which it inhibits by 50% the resorptive capacity of osteoclasts that for this drug has been reported as 2 x 10(-9) mol/L.

Biochemical markers of bone metabolism: an overview

OBJECTIVES

An overview of biochemical markers of bone metabolism is presented along with indications for their clinical utilization.

DESIGN AND METHODS

The structure, cyclical metabolism, and hormone regulation of bone is reflected by markers of resorption, formation and/or turnover. Markers of resorption representing degradation of type 1 collagen, include N-telopeptides, C-telopeptides, hydroxyproline, and the collagen crosslinks pyridinoline and deoxypyridinoline; acid phosphatase, a marker of osteoclast activity, and urinary calcium are also indicators of bone resorption. Bone formation markers indicate osteoblast activity; bone-specific alkaline phosphatase and the N-terminal and C-terminal extension peptides of procollagen reflect formation of organic matrix in bone. Osteocalcin, produced by osteoblasts but also released during osteoclastic degradation, may indicate either formation when resorption and formation are coupled or turnover when they are uncoupled.

RESULTS

Bone markers respond to intervention more rapidly than techniques such bone mineral density. Resorption markers respond approximately 1 to 3 months after intervention; markers of formation respond later, after 6 to 9 months. Bone markers may add useful information for assessing fracture risk and for monitoring osteoporosis, Paget's disease of bone, cancer metastasis, and metabolic disease. Various therapeutic interventions may affect release of some bone markers.

CONCLUSION

Bone disease has high prevalence in adults so bone markers will become even more important for assessing fracture risk and monitoring therapy as populations age. Characteristics of bone markers are dependent on biology and the assay used. Substantial work remains in characterizing existing assays, identifying better markers and performing the clinical studies to define which bone markers should be measured and when.

Increments in bone mineral density of the lumbar spine and hip and suppression of bone turnover are maintained after discontinuation of alendronate in postmenopausal women

PURPOSE

Previously we have reported a significant increase in bone mineral density (BMD) of the spine and the hip and reductions in biochemical indices of bone turnover in postmenopausal women with osteoporosis treated with alendronate at various doses over 1 to 2 years. We have followed BMD and biochemical parameters in these patients for 1 or 2 years after discontinuation of alendronate to determine resolution of alendronate effects.

PATIENTS AND METHODS

Participants received daily oral doses of placebo, 5 or 10 mg of alendronate for 2 years, or 20 or 40 mg of alendronate for 1 year followed by 1 year of placebo. No treatment was given in the third year of study.

RESULTS

Lumbar spine BMD changes in the 5- and 10-mg groups (-1.4 and -0.4%) were similar to those in the placebo group (-1.2%) 1 year after discontinuation of drug and lumbar spine BMD changes in the 20- and 40-mg groups (-1.2% and 0.8%) were similar to those in the placebo group (-0.9%) 2 years after discontinuation of drug. BMD of the total hip followed the same pattern of resolution. The difference in BMD between alendronate and placebo groups at the end of alendronate treatment was maintained up to 2 years. Residual reductions in the bone resorption markers urinary deoxypyridinoline (D-Pyr) and collagen type 1 cross-linked N telopeptides and the bone formation markers serum bone-specific alkaline phosphatase and osteocalcin remained for 1 year after discontinuation of 5 and 10 mg of alendronate and for 2 years after discontinuation of 20 and 40 mg of alendronate, other than return of D-Pyr to baseline 1 year after cessation of treatment with the 5- and 10-mg doses.

CONCLUSIONS

A residual decrease in bone turnover may be found up to 2 years after discontinuation of alendronate. Accelerated bone loss is not observed when treatment is discontinued. However, continuous therapy with alendronate is required to achieve a continuous gain in BMD.

Histomorphometric assessment of the long-term effects of alendronate on bone quality and remodeling in patients with osteoporosis

Treatment effects on bone quality and remodeling was assessed in postmenopausal women with osteoporosis treated with oral alendronate. One transiliac bone biopsy was obtained from 231 women at either 24 mo (n = 11) or 36 mo (n = 120) from the start of treatment with alendronate at doses of between 5 and 20 mg/d, or placebo. 64 biopsies at 24 mo (31 from the placebo group and 33 alendronate-treated patients) and 95 biopsies at 36 mo (40 from the placebo group and 55 alendronate-treated patients) provided adequate cancellous tissue, and were analyzed by histomorphometry. Mineral apposition rate was unaffected by treatment. At 24 and 36 mo, osteoid thickness, volume, and surface significantly decreased. At each of the doses studied, mineralizing surface and activation frequency significantly decreased at each time point (e.g., -92% and -87%, respectively, for the 10 mg daily dose after 2 yr). These diminutions were of the same magnitude for each dose at 24 mo, and for the two highest doses at 36 mo. A significant increase in wall thickness accompanied by a reduction in erosion depth was detected in biopsies obtained at 24 mo. These findings confirm that mineralization is normal, and trabecular bone turnover markedly decreased in patients receiving long-term dosing with alendronate. The findings also suggest that the observed increases in bone mineral density could result both from a reduction in the remodeling space due to a decreased activation frequency and a possible trend to a positive bone balance. In addition, further studies focused on a possible increase in the degree of mineralization of bone are required.

Prevention of early postmenopausal bone loss with cyclical etidronate therapy (a double-blind, placebo-controlled study and 1-year follow-up)

The objective of the study was to evaluate the effects of cyclical therapy with etidronate and calcium on spinal and femoral bone loss in the early post menopausal period. Fifty-four women, 53 +/- 2.8 yr old (mean +/- SD) and 2.3 +/- 1.3 yr post menopause received oral doses of either 400 mg/day etidronate for 2 weeks followed by 500 mg/day elemental calcium for 11 weeks, or placebo for 14 days followed by calcium for 11 weeks, repeated over a total of 24 months. A statistically significant increase in spinal bone mineral density (BMD) was observed after 6 months in the etidronate group. At 2 yr, the mean treatment differences in spinal and femoral neck BMD were +2.93% (P < 0.02) and 2.02% (P < 0.03), respectively. Serum osteocalcin and urinary crossLaps/creatinine excretion were decreased significantly by etidronate. Etidronate was well tolerated with a safety profile similar to that of placebo. Thirty-seven women participated in a 1-yr open-label follow-up study. Twelve months after treatment withdrawal, spinal BMD in the former etidronate group decreased by 1.43% and serum osteocalcin and urinary crossLaps returned to pretreatment values. In conclusion, cyclical etidronate is an effective therapy for the prevention of both trabecular and cortical bone loss in the early menopause and has a good safety profile.

Assessment of the performance of a capture immunoassay for the bone isoform of alkaline phosphatase in serum

We report the analytical validation of an immunocapture assay for the bone isoform of alkaline phosphatase in serum. A between batch imprecision of less than 10% was found, being about 8% at the upper limit of the reference range, and with a detection limit of 0.8 IU/l at 37 degrees C. The crossreactivity of the method with the liver isoform was found to be in the range of 3-13% depending on the method employed. Unexpectedly the correlation of results with a non-immunological method for the quantitation of bone ALP showed significant differences between samples from children and patients with Paget's disease, with an apparent lower level of capture in the case of children. These data suggest that there may be differences in the epitope recognised by the antibody, which may be due to the presence of different forms of bone enzyme in these two populations. The significance of these observations is not clear at this stage.