Cyclical clodronate is effective in preventing postmenopausal bone loss: a comparative study with transcutaneous hormone replacement therapy

Clodronate

Two early observations about the first generation bisphosphonate, clodronate, suggested that it would likely have clinical utility; specifically, it was a more potent anti-resorptive but a less potent inhibitor of mineralisation than its predecessor etidronate. The known mechanism of action differs from that of the later nitrogen-containing bisphosphonates, as clodronate is metabolised intracellularly to a toxic analog of adenosine triphosphate, AppCCl2p, which causes mitochondrial dysfunction, impaired cellular energy metabolism and osteoclast apoptosis. For pre-clinical studies in a variety of disease models, liposomal clodronate has become the agent of choice for macrophage depletion, for example in a recent study to enhance haematopoietic chimerism and donor-specific skin allograft tolerance in a mouse model. For clinical use, clodronate was developed in oral and injectable formulations; while poorly absorbed from the gastro-intestinal tract, its absorption at 1-3% of the administered dose is approximately three-fold higher than for nitrogen-containing bisphosphonates. Following an early setback due to an erroneous association with toxic adverse events, a number of successful clinical studies have established clodronate, predominantly in its oral formulations, as a highly successful treatment in Paget's disease, hypercalcaemia (benign and malignant), multiple myeloma, and early or metastatic breast cancer. Novel uses in other disease areas, including veterinary use, continue to be explored.

Clodronate: new directions of use

Clodronate is the father of bisphosphonates. For over three decades it has been subject of study in biological and clinical areas, proving to be an extremely interesting molecule from different points of view. It has been the first drug for osteoporosis that can be administered pulsatorily (once every 15 days or once a week). This, along with good tolerability, has been the first cause of its success, when there were no solid data in literature about its antifracture efficacy. There are three published studies that prove its antifracture effect: two by McCloskey published in 2004 and 2007 on BMR, and our study about fracture prevention in corticosteroids OP. In these studies a dose of 800 mg/day orally administered or 100 mg/week I.M. was used, and they are basically the same if you consider that clodronate absorption, orally administered, is on average 1.9%. However, a series of works where higher doses were used (1600 mg orally administered) with greater effectiveness on bone mass, especially in higher risk populations, lead us to consider the use of 200 mg i.m. formulation. First of all, we proved densitometric equivalence of 200 mg i.m./14 days and 100 mg i.m./week in a first study; then, in a second study, we proved a greater densitometric efficacy of 200 mg/week compared to 100 mg/week, clearer at femoral level, where the drug had not proven to prevent femoral fracture because of inadequate bone mass increase at that level. Moreover, as for ibandronate case, monthly dose was doubled compared to pivotal trial, in order to maximize the effects on femoral bone mass and therefore prevent femoral fractures. Consequently, on the basis of the risk envelope, whether it is identified according to BMD and the presence of one risk factor at least or more correctly identified through risk chart (FRAX or DeFRA), you can put forward a differential use of 100 mg i.m. and 200 mg i.m., weekly, "off-label" or every 14 days, adjusting doses in relation to fracture risk and painful symptoms gravity, as well as improving its ease of use and therefore assist compliance. Common experience and clinical and biological works have proved that clodronate has an analgesic effect that can be increased by doubling the doses. The analgesic effect is present not only with patients with fractures, but also with patients suffering from osteoarthritis or arthritis. Therefore, the drug would fit well in the therapeutic program of rheumatic patient, also because of its symptomatic effects. Clodronate at small doses (2 mg) could also have protective effects on cartilage (introduction of intra-articular formulation is expected) and at 10-100 fold higher doses it has certainly anti-inflammatory effects and more specifically antimacrophage and anticytokine effects (IL-1, IL-6, TNFalpha, PGE). These effects are amplified by putting clodronate in monolayer liposomes. This drug, therefore, has to be considered as adjuvant in arthritis therapy, whose origin can be linked to a strong osteoclastic activation caused by an increase of cytokines and the RANKL/OPG relationship. It is clear that clodronate can work on cytokine at first and on osteoclastic effector in the end. The drug has been used "off-label" for decades intravenously in complex regional pain syndrome (CRPS type 1) in relation to schemes that change according to different Authors and according to cumulative doses ranging from 3 to 5 g. The introduction on the market of the 200 mg i.m. formulation could allow to get more practical but equally effective schemes. For example, we used this scheme: 200 mg/day for 10 days and then 200 mg every other day for 20 days (cumulative dose of 4 g in a month). Said scheme can be repeated in the following months in particular cases. Results, as for efficacy and lack of relapses, show that clodronate is the leader drug for this syndrome. In recent years, relationship between costs and benefits has started to matter, especially after the creation of some algorithms, such as FRAX, that let us choose patients with a higher fracture risk in 10 years, and after pharmaceutic-economic models that let us calculate FRAX intervention threshold, on the basis of drug price and monitoring, antifracture efficacy, quality of life and how much a community can or wants to spend. In this respect, a sub-analysis of McCloskey's study on people over the age of 75, conducted on 3974 subjects, shows that clodronate is more efficient with patients with a higher fracture risk, calculated according to FRAX. Furthermore, another study by McCloskey revealed that, for a 100-pound/year drug (very similar to clodronate), 'cost effective' intervention threshold is about 7-10%. In conclusion, clodronate prevents fractures, decrease osteo-articular pain, is easy to handle, tolerable and had a great cost/benefit relationship.

Clinical utility of clodronate in the prevention and management of osteoporosis in patients intolerant of oral bisphosphonates

Bisphosphonates have a long history in the treatment of osteoporosis and bone-related disease. This review focuses on the use of a specific nonaminobisphosphonate, clodronate, which appears to be much better tolerated than other bisphosphonates and free of high-risk contraindications. Specifically, this paper reviews its use in the prevention of osteoporosis in postmenopausal women, taking into account its tolerability profile and recent safety issues arising regarding the use of bisphosphonates.

Clodronic acid formulations available in Europe and their use in osteoporosis: a review

Clodronic acid (Cl(2)-MBP [dichloromethylene bisphosphonic acid], clodronate) is a halogenated non-nitrogen-containing bisphosphonate with antiresorptive efficacy in a variety of diseases associated with excessive bone resorption. The drug is believed to inhibit bone resorption through induction of osteoclast apoptosis, but appears also to possess anti-inflammatory and analgesic properties that contrast with the acute-phase and inflammatory effects seen with nitrogen-containing bisphosphonates. Clodronic acid has been shown to be effective in the maintenance or improvement of bone mineral density when given orally, intramuscularly or intravenously in patients with osteoporosis. Use of the drug is also associated with reductions in fracture risk. The intramuscular formulation, which is given at a dose of 100 mg weekly or biweekly, is at least as effective as daily oral therapy and appears more effective than intermittent intravenous treatment. Intramuscular clodronic acid in particular has also been associated with improvements in back pain. The drug is well tolerated, with no deleterious effects on bone mineralization, and use of parenteral therapy eliminates the risk of gastrointestinal adverse effects that may be seen in patients receiving bisphosphonate therapy.

A double-blind placebo-controlled study of intravenous clodronate for prevention of steroid-induced bone loss in inflammatory bowel disease

BACKGROUND & AIMS

Osteoporosis is common in patients with inflammatory bowel disease (IBD). Corticosteroids induce a rapid and important bone loss. Clinical trials have shown oral bisphosphonates to effectively prevent steroid-induced bone loss. However, patients with IBD have been excluded from most of these studies because of potential digestive adverse events. Clodronate is a non-amino-bisphosphonate available in intravenous form without expected digestive (as oral bisphosphonates) or proinflammatory (as amine bisphosphonates) side effects. Our aim was to assess the efficacy of intravenous clodronate in preventing steroid-induced bone loss.

METHODS

A 12-month, double-blind, randomized, placebo-controlled trial was conducted in IBD patients beginning a steroid therapy. Sixty-seven patients (median disease duration, 38 mo; range, 1-240 mo) were randomized to receive one infusion per 3 months of either intravenous clodronate (900 mg, n = 33) or placebo. All the patients received calcium (1 g/day) and vitamin D (800 IU/day). The main outcome was the change in lumbar bone mineral density (BMD) between baseline and 1 year. Secondary outcomes included change in femoral neck BMD and adverse events.

RESULTS

After 1 year, there was no change in BMD in the clodronate group, neither at the spine (-0.2%, not significant) nor at the femoral neck (2.3%, NS). In contrast, there was a significant decrease in lumbar spine (-2.0%, P = .0018) and femoral neck (-1.7%, P = .045) BMD in the placebo group. Tolerance to treatment was good.

CONCLUSIONS

Intravenous clodronate is effective in the prevention of bone loss induced by steroids in patients with IBD.

Clodronic acid in the treatment of postmenopausal osteoporosis

BACKGROUND

Clodronic acid, a first-generation bisphosphonate, has been successfully used in the treatment of high bone turnover states, Paget's disease and osteolytic bone metastases. However, controversies remain over its optimal dosage and method of administration in the treatment of postmenopausal osteoporosis. In this study we aimed to evaluate the effect of clodronic acid treatment for 3 years on bone mineral density (BMD) in women with postmenopausal osteoporosis.

METHODS

This was a prospective, open-label, randomised, controlled study that was conducted in an outpatient clinic at the Bone Metabolism Unit of a tertiary referral centre university hospital. Thirty postmenopausal women (age range 48-73 years) with osteoporosis and a control group of 49 osteoporotic women (age range 47-74 years) received randomised therapy. The clodronic acid group of participants received oral doses of clodronic acid 800 mg plus elemental calcium 500 mg and 400 IU of vitamin D daily, while the control group was treated with calcium and vitamin D only. BMD was measured by dual energy x-ray absorptiometry at yearly intervals. Biochemical markers of bone turnover were also measured.

RESULTS

In this clinical study of postmenopausal women with osteoporosis, 36 months of clodronic acid treatment significantly increased average femoral neck BMD by 3.2 +/- 2.9%, trochanter BMD by 2.2 +/- 2.9% and lumbar spine BMD by 3.1 +/- 3%. In the control group, femoral neck, trochanter and lumbar spine BMD decreased by -6 +/- 2.7%, -7.3 +/- 2.5% and -5.4 +/- 2%, respectively (p<0.01, p<0.05 and p<0.05 for clodronic acid vs control, respectively). There was a significant decrease in urinary hydroxyproline (-38.3%) over 3 years in the clodronic acid group compared with baseline (p<0.05), while no significant change occurred in the control group. Clodronic acid was well tolerated and compliance was good. There were no clinically meaningful differences in the incidence of individual adverse events between the groups.

CONCLUSION

These results indicate that daily oral administration of clodronic acid 800 mg provides benefits to skeletal bone density in osteoporotic postmenopausal women. Calcium and vitamin D supplementation alone did not prevent further bone loss.

Endocrine Effects of Breast Cancer Treatment

OBJECTIVES

To discuss long-term physical effects of treatment for breast cancer including effects on reproductive, bone, sexual health, and related women's issues.

DATA SOURCES

Research articles, abstracts, literature reviews.

CONCLUSION

Long-term effects of treatment have become increasingly prevalent in breast cancer survivors. The most common are effects on reproductive, bone, and sexual health.

IMPLICATIONS FOR NURSING PRACTICE

Long-term effects of treatment can have a significant negative impact on the long-term health and QOL of women with breast cancer. Oncology nurses are well-positioned to anticipate and address the reproductive and endocrine consequences of breast cancer treatment.

Bisfosfonatos intravenosos

Bisphosphonates possess a fundamental role in the treatment of bone metabolic diseases. Yet their main limitations are poor oral absorption and gastrointestinal side effects, mainly esophageal irritation. Indeed, oral administration is unpleasant for many patients, and it is difficult in bed-confined subjects. Therefore, intravenous administration of these agents can be very useful in several clinical scenarios, especially to improve the compliance. Recently, it has been showed that intravenous bisphosphonates are very useful to control hypercalcemia of malignancy, and to prevent bone complications related to metastases. Their use has also been analyzed in the prevention of bone disease after organ transplantation. Thus, their application to control Paget's disease of bone is well-known, and probably they could have an important role as antiresorptive agents in postmenopausal and steroidal osteoporosis. We present here a state of the art of the use of intravenous bisphosphonates for the aforementioned disorders.

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.

Short-Term Intermittent Intravenous Clodronate in the Prevention of Bone Loss Related to Chemotherapy-Induced Ovarian Failure

Chemotherapy-induced ovarian failure causes rapid bone loss in premenopausal women with early breast cancer. The aim of the present study was to investigate the effect of intravenous intermittent clodronate during adjuvant chemotherapy in prevention of this rapid bone loss. 45 premenopausal women with early stage breast cancer were treated with adjuvant chemotherapy. In addition, all women were randomly allocated to receive either seven cycles of intravenous clodronate infusions (1500 mg each) parallel to the chemotherapy or no further therapy. The mean bone loss in the lumbar spine at 6 months was -0.5% in the clodronate group and -1.4% in the control group (p = 0.22) and, at 12 months, -3.9% and -3.6%, respectively (p = 0.62). Type I collagen metabolite PINP levels at six months were significantly lower in the clodronate group than in the control group: 22.6 microg/l (range 15.7-55.8 microg/l) and 44.0 microg/l (range 12.5-91.9 microg/l), respectively (p = 0.0001). At 12 months, no difference between the PINP levels in clodronate and control groups were seen. In conclusion, in this small study a short-term intermittent intravenous clodronate treatment did not seem to prevent clinically significantly the bone loss related to chemotherapy-induced ovarian failure in premenopausal women with early stage breast cancer, even though a significant reduction of a biochemical marker of bone turnover (PINP) was seen during the therapy.

Effects of oral ibandronate administered daily or intermittently on fracture risk in postmenopausal osteoporosis

Oral daily (2.5 mg) and intermittent ibandronate (between-dose interval of >2 months), delivering a similar cumulative exposure, were evaluated in 2946 osteoporotic women with prevalent vertebral fracture. Significant reduction in incident vertebral fracture risk by 62% and 50%, respectively, was shown after 3 years. This is the first study to prospectively show antifracture efficacy for the intermittent administration of a bisphosphonate.

INTRODUCTION

Bisphosphonates are important therapeutics in postmenopausal osteoporosis. However, they are currently associated with stringent dosing instructions that may impair patient compliance and hence therapeutic efficacy. Less frequent, intermittent administration may help to overcome these deficiencies. This study assessed the efficacy and safety of oral ibandronate administered either daily or intermittently with a dose-free interval of >2 months.

MATERIALS AND METHODS

This randomized, double-blind, placebo-controlled, parallel-group study enrolled 2946 postmenopausal women with a BMD T score < or = -2.0 at the lumbar spine in at least one vertebra (L1-L4) and one to four prevalent vertebral fractures (T4-L4). Patients received placebo or oral ibandronate administered either daily (2.5 mg) or intermittently (20 mg every other day for 12 doses every 3 months).

RESULTS AND CONCLUSIONS

After 3 years, the rate of new vertebral fractures was significantly reduced in patients receiving oral daily (4.7%) and intermittent ibandronate (4.9%), relative to placebo (9.6%). Thus, daily and intermittent oral ibandronate significantly reduced the risk of new morphometric vertebral fractures by 62% (p = 0.0001) and 50% (p = 0.0006), respectively, versus placebo. Both treatment groups also produced a statistically significant relative risk reduction in clinical vertebral fractures (49% and 48% for daily and intermittent ibandronate, respectively). Significant and progressive increases in lumbar spine (6.5%, 5.7%, and 1.3% for daily ibandronate, intermittent ibandronate, and placebo, respectively, at 3 years) and hip BMD, normalization of bone turnover, and significantly less height loss than in the placebo group were also observed for both ibandronate regimens. The overall population was at low risk for osteoporotic fractures. Consequently, the incidence of nonvertebral fractures was similar between the ibandronate and placebo groups after 3 years (9.1%, 8.9%, and 8.2% in the daily, intermittent, and placebo groups, respectively; difference between arms not significant). However, findings from a posthoc analysis showed that the daily regimen reduces the risk of nonvertebral fractures (69%; p = 0.012) in a higher-risk subgroup (femoral neck BMD T score < -3.0). In addition, oral ibandronate was well tolerated. Oral ibandronate, whether administered daily or intermittently with an extended between-dose interval of >2 months, is highly effective in reducing the incidence of osteoporotic fractures in postmenopausal women. This is the first time that significant fracture efficacy has been prospectively shown with an intermittently administered bisphosphonate in the overall study population of a randomized, controlled clinical trial. Thus, oral ibandronate holds promise as an effective and convenient alternative to current bisphosphonate therapies.

A tolerability andpharmacokinetic study of a newinjectable formulation of disodium clodronate in healthyfemale volunteers

Disodium clodronate (dichloromethylene bisphosphonic acid, disodium salt; CAS 22560-50-5) is a bisphosphonate that has demonstrated efficacy in patients with a variety of diseases of enhanced bone resorption. Intramuscular clodronate can determine pain at the injection site, it is therefore particularly useful to co-administer a local anaesthetic with clodronate to reduce pain at the injection site. The tolerability and pharmacokinetic of a new formulation of 100 mg disodium clodronate containing 1% lidocaine (test formulation, Chiesi Farmaceutici S.p.A) were investigated in comparison to the same formulation without the local anaesthetic (Clody) and a marketed formulation containing 1% benzyl alcohol (Clasteon). Thirty healthy female volunteers were treated according to a single dose, double-blind, randomised, three-way cross-over design. The local tolerability was investigated by assessing reddening and hardening at the injection site, and plasma CPK levels. Pain intensity was investigated on the VAS (visual analogue scale) and on the VRS (verbal rating score). Urinary clodronic acid concentrations were determined using a validated specific GC/MS/NCI assay. The statistical analysis on pain assessment showed a significant reduction of pain intensity immediately and up to 2 hours after administration of the new formulation compared to the marketed ones. CPK levels and occurrence of hardening at the injection site did not show statistically significant differences between formulations. No local redness was reported. Clodronate urinary excretion during the 48 h collection interval was not statistically different among the formulations and the 95% confidence intervals were inside the bioequivalence acceptance region, demonstrating comparable bioavailability. It was concluded that the investigated new formulation of 100 mg disodium clodronate was better tolerated than the reference marketed formulations.

Intravenous bisphosphonate therapy for osteoporosis: where do we stand?

The use of oral bisphosphonates, particularly members of the aminobisphosphonate subclass, is well established for the treatment of osteoporosis. In a number of clinical settings, intravenous administration appears to be advantageous. However, current dosing and efficacy data are limited while definitive, long-term trials with some of these agents are ongoing. In this article, we review the available information and discuss the use of these drugs on that basis.

Circadian variation in biochemical markers of bone cell activity and insulin-like growth factor-I in two-year-old horses

Studies in humans have found circadian changes to be one of the most important sources of controllable preanalytical variability when evaluating bone cell activity using biochemical markers. It remains unclear whether similar circadian changes influence bone marker concentrations in the horse. The aim of this study was to characterize changes in serum concentrations of three biochemical markers of bone cell activity over a 24-h period in six 2-yr-old Thoroughbred mares, and to determine circadian variability in IGF-I, which regulates bone turnover. Three bone markers were measured in serum: osteocalcin, a marker of bone formation, the carboxy-terminal propeptide of type-I collagen (a marker of bone formation), and the carboxy-terminal telopeptide of type-I collagen (a marker of bone resorption). Data were analyzed using the cosinor technique, which fits a 24-h cycle to each dataset. A significant circadian rhythm was observed for osteocalcin (P = 0.028), with an estimated amplitude of 7.6% of the mean (95% confidence interval 1.3% to 16.3%), and an estimated peak time of 0900. However, the observed rhythm for the carboxy-terminal telopeptide of type-I collagen (amplitude = 7.4%) was not significant (P = 0.067), and there were no significant changes in concentrations of the carboxy-terminal propeptide of type-I collagen over the 24-h study period (P = 0.44). There was a small but significant circadian rhythm for IGF-I (P = 0.04), with an estimated amplitude of 3.4% (95% confidence interval 0.2 to 7.1%) and peak at 1730. Further studies are now required to determine the potential association between circadian changes in IGF-I and osteocalcin in the horse. Although no significant circadian variation was found in concentrations of the car-boxy-terminal propeptide of type-I collagen and the carboxy-terminal telopeptide of type-I collagen, this may in part be a result of the age of the animals that were still skeletally immature. Future studies should aim to determine whether these markers develop a circadian rhythm at a later age when growth is complete. In the meantime, consistency in time of sampling should continue to be considered best practice when measuring biochemical markers of bone turnover in the horse.

Injectable bisphosphonates in the treatment of postmenopausal osteoporosis

Osteoporosis is a "silent" disease and the patient has usually no clue of it until the occurrence of a fragility fracture. Prevention requires a continuous daily treatment that could be uncomfortable to the patient. Besides the recently introduced weekly oral schedules, injectable bisphosphonates have often been used as an off-label option to ameliorate compliance. In general, although with different efficiency, almost all injectable bisphosphonates can improve bone mineral density and suppress bone resorption markers. The effect of intravenous infusions of bisphosphonates are, to a large extent, similar to equivalent intramuscular administrations, but doses and dosing intervals represent the critical issues. Pain at the injection site and acute phase reactions are relatively common to intramuscular clodronate and intravenous infusions of nitrogen-containing bisphosphonates, respectively. Under certain circumstances, intermittent treatment with injectable bisphosphonates might represent a feasible alternative when compliance is at risk.

Clodronate: mechanisms of action on bone remodelling and clinical use in osteometabolic disorders

Clodronate (CI2MBP) is a non-aminated bisphosphonate that inhibits bone resorption. Studies on the mechanisms of action of this molecule on bone metabolism have been limited and only recently has information on the molecular machinery that underlies its effects on the bone remodelling process become available. Pharmacological and clinical studies have demonstrated the effectiveness of clodronate in the treatment of postmenopausal osteoporosis and in all conditions of excessive bone resorption, such as Paget's disease, hypercalcaemia of malignancy and osteolytic metastases. Clodronate is the only bisphosphonate currently available on the market for both oral and parenteral administration. Treatment with clodronate via intramuscular administration of doses of 100 mg/week has shown significant effects on bone mineral density after 6 months in patients with postmenopausal osteoporosis and these effects are maintained 3 years after the start of the treatment. In a recent controlled clinical study, a significant increase in bone mineral density was observed, associated with a 46% reduction in the incidence of vertebral fractures. However, most relevant studies have been small, unblinded and short-term and have not systematically examined the effects of the dose and dosing intervals on bone mineral density and markers of bone turnover. Ongoing controlled clinical studies may offer answers regarding potential use of clodronate in osteoporosis and also about dosage of intermittent administration. This review summarises the accumulated knowledge in the mechanisms of action of clodronate on bone remodelling. Moreover, the clinical trials on the use of clodronate in metabolic bone diseases are described in-depth. We believe that this work will help to better focus on the need for more research on a compound which has potential applications in prevention and therapy of osteoporosis. However, studies that demonstrate an effect on the rate of fractures are needed before any recommendation can be made.

Effect of cyclical intravenous clodronate therapy on bone mineral density and markers of bone turnover in patients receiving home parenteral nutrition

BACKGROUND

Patients receiving home parenteral nutrition (HPN) because of intestinal failure are at high risk of developing osteoporosis.

OBJECTIVE

We studied the effect of the bisphosphonate clodronate on bone mineral density (BMD) and markers of bone turnover in HPN patients.

DESIGN

A 12-mo, double-blind, randomized, placebo-controlled trial was conducted to study the effect of 1500 mg clodronate, given intravenously every 3 mo for 1 y, in 20 HPN patients with a bone mass T score of the hip or lumbar spine of less than -1. The main outcome measure was the difference in the mean percentage change in the BMD of the lumbar spine measured by dual-energy X-ray absorptiometry. Secondary outcome measures included changes in the BMD of the hip, forearm, and total body and biochemical markers of bone turnover, ie, serum osteocalcin, urinary pyridinoline, and urinary deoxypyridinoline.

RESULTS

The mean (+/-SEM) BMD of the lumbar spine increased by 0.8 +/- 2.0% in the clodronate group and decreased by 1.6 +/- 2.0% in the placebo group (P = 0.43). At all secondary skeletal sites (ie, hip, total body, and distal forearm), we observed no changes or small increases in the BMD of the clodronate group and decreases in the BMD of the placebo group. In the clodronate group, biochemical markers of bone resorption decreased significantly (P < 0.05).

CONCLUSIONS

Clodronate significantly inhibits bone resorption as assessed by changes in biochemical markers of bone turnover. Although the mean BMD increased in the clodronate group, cyclic clodronate therapy failed to increase spinal BMD significantly at 12 mo.

Meta-analyses of therapies for postmenopausal osteoporosis. V. Meta-analysis of the efficacy of hormone replacement therapy in treating and preventing osteoporosis in postmenopausal women

OBJECTIVE

To review the effect of hormone replacement therapy (HRT) on bone density and fractures in postmenopausal women.

DATA SOURCE

We searched MEDLINE and EMBASE from 1966 to 1999, the Cochrane Controlled Register, citations of relevant articles, and proceedings of international meetings for eligible randomized controlled trials. We contacted osteoporosis investigators to identify additional studies, and primary authors for unpublished data.

STUDY SELECTION

We included 57 studies that randomized postmenopausal women to HRT or a control (placebo or calcium/vitamin D) and were of at least 1 yr in duration. Seven of these studies reported fractures.

DATA ABSTRACTION

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

DATA SYNTHESIS

HRT showed a trend toward reduced incidence of vertebral fractures [relative risk (RR) 0.66, 95% confidence interval (CI) 0.41-1.07; 5 trials] and nonvertebral fractures (RR 0.87, 95% CI 0.71-1.08; 6 trials). HRT had a consistent effect on bone mineral density (BMD) at all sites. The difference between HRT and control in the percent change in bone density at 2 yr was 6.76 (5.83, 7.89; 21 trials) at the lumbar spine and 4.53 (3.68, 5.36; 14 trials) and 4.12 (3.45, 4.80; 9 trials) at the forearm and femoral neck, respectively.

CONCLUSIONS

HRT has a consistent, favorable and large effect on bone density at all sites. The data show a nonsignificant trend toward a reduced incidence in vertebral and nonvertebral fractures.

Bone metabolism during the perimenopausal transition: a prospective study

OBJECTIVE

Changes in biochemical markers of bone formation and resorption were followed over the course of 1 year in premenopausal, perimenopausal and early postmenopausal women.

METHODS

Sixty-four subjects were analyzed, grouped according to their menstrual pattern, menopausal complaints and endocrinological parameters to be premenopausal (n=20), perimenopausal (n=24) or early postmenopausal (n=20). The parameters studied at four visits during the 12-month study period were the urinary pyridinium cross-links pyridinoline (PYD) and deoxypyridinoline (DPD), and N-terminal telopeptide (NTX) as bone resorption markers, as well as osteocalcin (OC) and bone-specific alkaline phosphatase (BAP) in serum, representing bone formation. The longitudinal changes over time as well as intergroup differences were analyzed using generalized estimating equations (GEE) in connection with Wald statistics.

RESULTS

Over the course of 1 year BAP levels decreased in the late premenopausal group (P<0.05). The perimenopausal group exhibited significant changes of PYD, DPD and OC (P<0.01), NTX levels were higher than in premenopause. Postmenopausal subjects had elevated NTX values, while PYD and DPD levels remained close to the perimenopausal range. Only for OC a time effect was seen during postmenopause.

CONCLUSIONS

Changes in bone turnover already begin in late premenopause, when decreased bone formation may precede increased bone resorption. The rise of NTX from late premenopause through early postmenopause indicates diagnostic sensitivity of this parameter to changes in bone metabolism induced by estrogen withdrawal. PYD and DPD do not follow this pattern, but change significantly with time during perimenopause to then remain largely unchanged in early postmenopause.

Long-term impact of chemotherapy-induced ovarian failure on bone mineral density (BMD) in premenopausal breast cancer patients. The effect of adjuvant clodronate treatment

We present the 5-year results of the effect of adjuvant chemotherapy on bone mineral density (BMD) and the efficacy of clodronate in the prevention of bone loss in 73 premenopausal women with primary breast cancer. All patients were treated with cyclophosphamide, methotrexate, 5-fluorouracil (CMF) chemotherapy. The patients were randomised to oral clodronate 1600 mg daily for 3 years or to a control group. At 5 years, patients were divided into those with preserved menstruation and those with amenorrhoea. Changes in BMD correlated significantly with the menstrual function after chemotherapy. The change in the lumbar spine BMD at 3 and 5 years were +0.6 and -1.3% in the menstruating group and -7.5 and -10.4% in the amenorrhoeic group (P=0.0001 and 0.0001, respectively), and in femoral neck +1.7 and -0.3%, and -3.5 and -5.8% (P=0.002 and P=0.001, respectively). Three-year clodronate treatment significantly reduced the bone loss in the lumbar spine -3.0% compared with controls -7.4% at three years (P=0.003), but no significant difference was found in the femoral neck: -1.7% versus -2.8%, respectively (P=0.86). These differences between the study groups were still seen at 5 years: in the lumbar spine -5.8% versus -9.7% (P=0.008) and femoral neck -3.5% versus -5.1% (P=0.91). In conclusion, chemotherapy-induced ovarian failure in premenopausal women caused a temporary accelerated bone loss of the lumbar spine. Adjuvant clodronate treatment significantly reduced this bone loss. Two years after the termination of treatment, the bone loss was still significantly less in the clodronate group compared with the control group.

Osteoporosis therapies for rheumatoid arthritis patients: minimizing gastrointestinal side effects

OBJECTIVE

This manuscript identifies characteristics that put people with rheumatoid arthritis (RA) at high risk for osteoporosis or gastrointestinal (GI) disturbances. The manuscript then reviews therapies available for osteoporosis in the United States and makes recommendations about choosing therapies that minimize GI adverse effects in RA patients at high risk for such events.

DATA SOURCES

References identified through MEDLINE, abstracts, and prescribing information for individual drugs.

DATA EXTRACTION

Characteristics that predispose patients to osteoporosis and GI problems were identified. Data on individual osteoporosis therapies were assessed by risk-benefit analysis and appropriateness for use in patients at risk for GI disturbances.

DATA SYNTHESIS

High risk of osteoporosis in people with RA is caused by disease activity, medication effects, physical inactivity, and standard risk factors such as postmenopausal status and increased age. Patients with RA are frequently at high GI risk if they are receiving nonsteroidal anti-inflammatory drugs or corticosteroids. Because of the high potential for erosive esophagitis and other upper GI disorders with alendronate, caution is warranted in prescribing alendronate to RA patients with high GI risk. In such patients, estrogen replacement therapy, selective estrogen receptor modulators, or calcitonin should be considered for treatment, and either estrogen replacement therapy or selective estrogen receptor modulators should be considered for osteoporosis prevention.

CONCLUSIONS

Assessment of GI risk is important in patients with RA and osteoporosis. Risk factors should be considered when choosing osteoporosis therapies.

Comparison of different treatment modalities for postmenopausal patients with osteopenia: hormone replacement therapy, calcitonin and clodronate

OBJECTIVE

To evaluate the effectiveness of hormone replacement therapy (HRT), clodronate, calcitonin and a clodronate plus calcitonin combination in postmenopausal patients with osteopenia.

METHODS

One hundred postmenopausal patients with osteopenia, with bone mineral density (BMD) measurements at least one standard deviation below the mean value for young premenopausal subjects (T score < -1), were studied. They had no contraindications to HRT, clodronate or calcitonin use and were randomized to four different treatment groups. Patients in group I were treated with transdermal estradiol 50 micrograms/day and oral medroxyprogesterone acetate 10 mg/day during the last 12 days of the month; group II received oral clodronate 400 mg/day for 1 month out of every 3 months; group III received calcitonin nasal spray 100 IU/day; and patients in group IV were treated with oral clodronate 400 mg/day for 1 month out of every 3 months plus calcitonin nasal spray 100 IU/day. Elementary calcium 1000 mg/day was supplemented to patients in all groups. Spinal and femoral neck BMD measurements and markers of bone mineral metabolism were measured in each patient before treatment and 6, 12 and 18 months after treatment in 86 patients.

RESULTS

Significant increases in mean lumbar spine BMD were found in the group receiving HRT, and at the end of 18 months there was a 2.69 +/- 0.76% increase, compared with baseline. Mean femoral neck BMD also increased by 2.22 +/- 0.57% in the HRT group; this was significantly different from baseline, resulting in a higher bone mass gain than in the other three groups. Increases in both lumbar spine and femoral neck BMD were found in patients treated with clodronate, although the only significant increase was observed in lumbar spine BMD at the end of 18 months. The mean changes in BMD were not significantly different, compared with the other groups, and at the end of 18 months there was a 2.20 +/- 0.58% increase at the lumbar spine. The mean vertebral and femoral neck BMD did not change significantly throughout the study period in patients receiving calcitonin. At the end of 18 months, there was a 0.13 +/- 0.52% decrease and a 0.11 +/- 0.49% increase in mean lumbar spine and femoral neck BMD, respectively, compared with baseline. The combination of clodronate plus calcitonin increased mean lumbar spine and femoral neck BMD by 2.08 +/- 1.05% and 1.46 +/- 1.09%, respectively, at the end of 18 months, but these increases were not significantly different from those in the groups where these agents were used alone. Significant decreases in bone resorption and in markers of bone formation were observed in all groups.

CONCLUSION

HRT was found to be the most effective treatment regimen in postmenopausal patients with osteopenia, compared with clodronate, calcitonin and a clodronate plus calcitonin combination. Clodronate or calcitonin might be alternatives when HRT is contraindicated or refused by the patient; although calcitonin was found to be less effective. The clodronate plus calcitonin combination was not superior to either of these agents when used alone.

Monitoring individual response to hormone replacement therapy with bone markers

Hormone replacement therapy (HRT) induces a rapid decrease in biochemical markers of bone turnover that correlate with a subsequent increase in bone mineral density (BMD). To determine the utility of bone markers in the management of postmenopausal women receiving HRT, we analyzed the relationship between changes in four markers (serum osteocalcin and bone alkaline phosphatase [BAP], serum and urinary C-telopeptide of type I collagen [CTX]) and changes in spine BMD in 569 women treated for 2 years with different doses of a matrix transdermal 17beta-estradiol patch in two placebo-controlled trials. Using a logistic regression model, we found that both the percent change from baseline and the actual value of resorption markers at 3 and 6 months of treatment were predictive of BMD response at 2 years. Comparable results were obtained with formation markers at 6 months only. We determined the sensitivity, probably of positive BMD response, and corresponding cutoff value of markers at 3 and 6 months with a specificity set at a level of 0.90, so that <10% of women classified with markers as responders, i.e., as having a subsequent increase in BMD at 2 years >/=2.26%, would be false positive. All markers provided a high probability of positive BMD response ranging from 0.82 to 0.91, with a sensitivity higher for resorption than for formation markers, and sometimes improved in a model combining the percent change and the actual value of marker under HRT. For example, a decrease in serum CTX >/= 33% at 3 months of HRT provided a 68% sensitivity and 87% probability of positive BMD response at 2 years for a 90% specificity. At 6 months, a decrease in urinary CTX >/= 53% provided a 68% sensitivity and 91% probability of a positive BMD response for a 90% specificity. Half of false-negative cases at 3 months will be correctly identified by a subsequent urinary CTX measurement at 6 months. We conclude that the short-term change in bone markers reflects long-term changes of BMD in postmenopausal women treated with HRT. Our data suggest that bone turnover markers can be used to monitor the BMD response to HRT at the individual level. Whether such monitoring could improve long-term compliance to HRT should be tested prospectively.

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.

Developments in the therapeutic applications of bisphosphonates

The authors review the structural, pharmacologic, and clinical aspects of bisphosphonates, a class of drugs currently used to treat several disorders of bone and calcium metabolism. Pertinent literature on the bisphosphonates was reviewed with the help of a MEDLINE search and several bibliographies, including published clinical trials, monographs, and review articles. The bisphosphonates are analogs of pyrophosphate that, when given orally or intravenously, bind avidly to exposed bone mineral and disrupt bone turnover. These agents comprise three groups or generations, based on their potency and chemical structures. All three generations are effective in treating hypercalcemia, Paget's disease of bone, osteoporosis, and other disorders of accelerated bone turnover. The third-generation agents have the greatest potency and offer the promise of a convenient way to suppress or prevent osseous metastasis in patients with certain malignancies. As a group, these agents are well tolerated and, when administered correctly, rarely cause toxicity. The bisphosphonates are safe and effective agents for the treatment of disorders of accelerated bone turnover.

Intramuscular clodronate therapy in postmenopausal osteoporosis

Long-term daily administration of oral bisphosphonates has been effective in the treatment of postmenopausal osteoporosis, but the duration, mode and cost of the therapy may sometimes affect patient compliance. In Italy, the bisphosphonate clodronate is also available via the intramuscular (i.m.) route of administration, and the present study was performed to test its efficacy in postmenopausal osteoporosis. Ninety osteoporotic postmenopausal women were enrolled in a randomized, controlled 3 year study. The diet of all patients was adjusted to provide 1200-1300 mg of calcium daily, eventually by administration of supplements. Patients were randomly assigned to no therapy (30 patients) or to receive clodronate 100 mg i.m. either every 2 weeks (30 patients) or 1 week (30 patients). The i.m. injection caused substantial pain at the site of injection, which led to treatment withdrawal in almost 50% of the patients receiving weekly dosing. In control patients, a progressive, slow decline in spine and femoral bone mineral density (BMD), which became statistically significant at the end of the second year of observation, was observed. In the patients given weekly i.m. clodronate, spinal BMD rose by 3.8% (+/-7.3 SD) within 6 months. A slight, nonsignificant increase was observed thereafter, such that, at the completion of 3 years of observation, the mean gain was 4.5% (+/-6.3). In the patients treated with injections of 100 mg of clodronate every two weeks the increase in BMD was somewhat lower and slower, becoming significant only at month 24 (2.9+/-4.6%). In none of the two active groups was the femoral neck BMD changed significantly during the 3 years of the study. A significant increase in trochanter and Ward's triangle BMD was observed at month 12 only in the patients on the highest dose of clodronate. In both groups treated, the hip BMD changes were significantly different from those observed in control patients. The biochemical markers of bone turnover were suppressed in both clodronate groups. These results indicate that intermittent i.m. clodronate administration can provide clinically relevant benefits to skeletal bone density in osteoporotic postmenopausal women, but the in situ pain may limit its extensive use.

Meta-analysis about efficacy of anti-resorptive drugs in post-menopausal osteoporosis

OBJECTIVE

The purpose of this study was to compare the effect of three groups of anti-resorptive drugs in post-menopausal osteoporosis.

DATA SOURCES

We collected data covering the period between 1983 and 1995, by first using MEDLINE. References retrieved were scanned further to identify additional papers.

STUDY SELECTION

Only randomized studies evaluating bone mass by means of dual-photon or dual energy densitometry over a period of 1 year were accepted.

DATA EXTRACTION

Studies were arranged into three drug groups. We used densitometry results after 1 year in all treatment or control groups. Factors which might interfere with the results were recorded for subsequent separate analysis.

DATA SYNTHESIS

The MEDLINE search identified almost 25,000 studies. On reading the abstracts, 275 trials appeared to be controlled trials and original copies were retrieved for detailed analysis. A total of 31 articles which satisfied the inclusion criteria were identified. The first meta-analysis included studies which compared oestrogens and placebo, and the global effect-size was 0.54 (95% CI 0.34, 0.73). The second meta-analysis compared calcitonins with placebo and produced an effect-size of 0.41 (95% CI 0.21, 0.61) The third analysis compared bisphosphonates and placebo and showed an effect-size of 0.87 (95% CI 0.68, 1.07). Only oestrogen dose affected the results found.

CONCLUSIONS

Bisphosphonates had the greatest effect on bone mass in post-menopausal osteoporosis.

Bisphosphonates and osteoporosis treatment in Italy

A treatment against osteoporosis can be considered efficacious only when its beneficial effects on bone remodeling, bone mass, and osteoporotic fracture incidence are proven. As for any treatment, proven efficacy must be combined with proven safety. This review analyzes published data on efficacy and safety of alendronate, clodronate and etidronate, the bisphosphonates currently marketed in Italy for osteoporosis treatment. Different studies have shown that alendronate, clodronate and etidronate reduce bone turnover, and increase bone mineral density in postmenopausal osteoporotic patients. Prospective, double blind, multicenter studies reported a reduction in osteoporotic fracture incidence for alendronate and etidronate. Fracture incidence reduction by clodronate, on the other hand, was shown only in an open label study. Finally, a reduction in fracture incidence by etidronate was shown in a large retrospective postmarketing study. Postmarketing surveillance evidenced that osteomalacia, a suspected side effect of etidronate treatment, does not occur at the currently used dose regimens. Postmarketing surveillance of alendronate has recently raised some concern regarding possible severe esophageal damage during alendronate treatment, especially when the drug is not taken according to the manufacturer's instructions.

A systematic review of the skeletal effects of estrogen therapy in postmenopausal women. I. An assessment of the quality of randomized trials published between 1977 and 1995

PURPOSE

To examine the quality of published randomized controlled trials of the effects of estrogen treatment on fracture risk and measures of bone mass.

DATA SOURCES

Articles on estrogen treatment for osteoporosis published between 1977 and 1995 were identified by searching Medline and Excerpta Medica databases and bibliographies of original papers and published reviews.

STUDY SELECTION

Studies selected were randomized controlled trials of the efficacy of estrogens in preventing loss of bone mass or fractures in postmenopausal women.

DATA EXTRACTION

Data extraction and quality assessment were performed in duplicate, with assistance of a manual. Raters were blinded as to authors and their affiliations and the publication details.

RESULTS

Of 99 eligible randomized controlled trials published between 1977 and 1995, eight included no extractable data, and 23 contained results that were published in duplicate. Total quality scores increased over time, but this was accounted for by improvements only in the measurement technologies used to estimate bone mineral content or density. There was no improvement in the quality of randomization methods, the extent to which withdrawals were accounted for, or in the baseline comparability of treated and control patients. Neither sample sizes nor durations of follow-up increased over time.

CONCLUSIONS

This body of literature fails to address whether estrogen therapy reduces fracture rates, and does not allow for comparison of the effects of different active therapies on change in bone density. Although there were improvements in the techniques for estimating bone mass and delivering estrogen treatment, the studies published in the 1990s were no more informative for making clinical or policy decisions than those published in the 1970s.

Treatment of osteoporosis with bisphosphonates

Several bisphosphonates are effective for preventing bone loss associated with estrogen deficiency, glucocorticoid treatment, and immobilization, and for at least partially reversing bone loss in patients with postmenopausal osteoporosis and steroid-induced osteoporosis. The most promising of these agents are etidronate, alendronate, risedronate, and ibandronate. These drugs should have an important role in the prevention and treatment of osteoporosis; however, more research is needed regarding optimal doses and regimens (continuous versus intermittent, oral versus parenteral), comparisons with other agents, and their use in combination with other agents.

A systematic review of the skeletal effects of estrogen therapy in postmenopausal women. II. An assessment of treatment effects

PURPOSE

To combine the results of randomized controlled trials to provide overall estimates of the effect of estrogen treatment on fracture rates and measures of bone mass.

DATA SOURCES

Articles on estrogen treatment for osteoporosis published between 1977 and 1995 were identified.

STUDY SELECTION

Studies selected were randomized controlled trials of the efficacy of estrogens in preventing loss of bone mass or fractures in postmenopausal women.

DATA EXTRACTION

Data extraction and quality assessment were performed in duplicate, with assistance of a manual. Raters were blinded as to authors and their affiliations and the publication details. With estimates of bone mass, the treatment effect size was defined as the difference in the mean annual change in bone mass between the treatment and control groups divided by the pooled standard deviation for change. In the case of fractures, efficacy was measured as the reduction in the numbers of individuals experiencing new fractures with treatment. Effect sizes were pooled using the random effects model.

RESULTS

Thirty-seven studies met the criteria for inclusion in the systematic review. Only one small secondary prevention trial contained evaluable data on vertebral fractures. This study found a fracture relative risk of 0.63 (95% confidence interval, CI 0.28-1.43) with estrogen treatment. There was more information on the effects of treatment on bone mass. Overall effect sizes ranged between 0.5 and 2.5 standard deviation (SD) units for change. A dose-response relationship was apparent but high doses of estrogens were not associated with effect sizes greater than those observed with recommended doses. There was no significant difference in efficacy between transdermal and oral administration of estrogens. Pooling of paired data from secondary prevention studies indicated that treatment effect sizes were smaller at the hip (0.92, 95% CI 0.3-1.5 SD units) than at the spine (2.1, 95% CI 0.9-3.3 SD units). No significant effects of co-intervention with calcium, progestogens or androgens were seen, although an additive effect of higher doses of calcium could not be ruled out.

CONCLUSIONS

Clear-cut effects of estrogens in attenuating the postmenopausal decline in estimated bone mass were apparent in this literature. However, the trials were short-term and provide inadequate evidence on the effects of treatment on fracture risk.

Oral clodronate and reduction in loss of bone mineral density in women with operable primary breast cancer

BACKGROUND

Women with primary breast cancer who receive systemic therapy may experience ovarian failure or early menopause, leading to a loss of bone mineral density (BMD). Loss of BMD may be reduced by use of bisphosphonates, compounds that inhibit the action of osteoclasts (cells that absorb or remove bone tissue). We have conducted a double-blind, randomized, two-center trial to evaluate BMD in women with primary breast cancer who were given the bisphosphonate clodronate (1600 mg/day orally) or placebo for 2 years.

METHODS

From August 31, 1990, through March 31, 1996, more than 300 eligible patients had been accrued, randomly assigned to study treatment, given the appropriate primary surgical care and systemic (chemotherapy and/or tamoxifen) therapy, and had completed follow-up for at least 1 year. BMD in the lumbar spine and in the hip, including the trochanteric area, was measured by use of dual-energy x-ray absorptiometry at the beginning of treatment and after 1 and 2 years of treatment. Changes in BMD were calculated as percent changes from the initial readings. Treatment effects for clodronate versus placebo (i.e., mean percent changes in BMD with clodronate minus mean percent changes in BMD with placebo) at 1 and 2 years for individual sites were calculated.

RESULTS

After 1 year, the treatment effects for clodronate versus placebo in the lumbar spine, the total hip, and the trochanter, respectively, were as follows: +2.38% (95% confidence interval [CI] = 1.36-3.41), +0.74% (95% CI = -0.13 - 1.60), and +1.29% (95% CI = 0.24-2.34). After 2 years, the corresponding treatment effects were +1.72% (95% CI = 0.12-3.34), +1.85% (95% CI = 0.51-3.20), and +2.30% (95% CI = 0.66-3.94), respectively.

CONCLUSIONS

Oral clodronate appears to reduce the loss of BMD in patients who receive treatment for primary breast cancer.

Osteoporosis: trials and tribulations

A 30-50% reduction in fracture risk produced by a drug is biologically "worthwhile." The detection of this benefit, when truly present, is a challenge requiring large studies of 3-5 years' duration, because only a small number of women at risk actually sustain a fracture during this time. For example, in any year, fractures occur in 1-2 per 100 women approximately 65 years of age, 6-10 per 100 women approximately 75 years of age, and only 1-2 per 2,000 of the 15% of women < 60 years of age with osteoporosis. An appreciation of this low annual event rate is important because (1) it helps patients to understand their illness, (2) it determines the power of clinical trials, (3) it underscores the large numbers of patients that must be treated to prevent one fracture, and (4) it underscores the need for safety, particularly in groups at low absolute risk of fracture; all are exposed to drug side effects, and the vast majority derive no benefit from treatment because they would not have had a fracture without it, despite being at risk. Few studies have met the design requirements needed to identify the antifracture efficacy of a drug when it really exists, namely, (1) large patient samples randomized to treatment or placebo for 3-4 years, (2) blinding throughout follow-up, (3) statistical analyses of preplanned comparisons using intention to treat, and (4) avoidance of statistical analyses of associations discovered by post hoc analyses. Moreover, (5) few studies have assessed long-term safety and quality of life. Consequently, the uncertainty regarding efficacy and safety of available treatments may be more of a problem of the design, execution, and interpretation of the clinical studies than of the drugs themselves. In the reduction of vertebral fracture risk, the greatest optimism exists for hormone replacement therapy (HRT) and the bisphosphonates. HRT reduces bone turnover, increases bone mineral density (BMD), and decreases vertebral fracture rates by approximately 40%, even in women > 70 years of age. Reduction in hip fracture risk with HRT has been reported in observational studies. Two rigorously conducted studies provide credible evidence that the bisphosphonate alendronate reduces the risk of vertebral and hip fractures by approximately 40-50%. Etidronate, calcitonin, and 1,25-dihydroxyvitamin D3 may reduce risk of vertebral fracture; however, problems in study design leave uncertainty. Although 2 trials using fluoride suggest a reduction in fracture rates, the more rigorously conducted trials do not, despite having adequate power to do so. Calcium supplements are likely to slow bone loss, but reduction in fracture risk is uncertain. Vitamin D and calcium supplementation reduce risk of hip fracture in nursing home residents but not in community residents. There have been no studies of the efficacy of any treatment to prevent hip or vertebral fractures in men or in corticosteroid-related osteoporosis. The treatment of osteoporosis is becoming a reality. HRT and the bisphosphonates, particularly alendronate, appear to be the best options at present.

Bisphosphonates: preclinical aspects and use in osteoporosis

The bisphosphonates are synthetic compounds characterized by a P-C-P bond. They have a strong affinity to calcium phosphates and hence to bone mineral. In vitro they inhibit both formation and dissolution of the latter. Many of the bisphosphonates inhibit bone resorption, the newest compounds being 10,000 times more active than etidronate, the first bisphosphonate described. The antiresorbing effect is cell mediated, partly by a direct action on the osteoclasts, partly through the osteoblasts, which produce an inhibitor of osteoclastic recruitment. When given in large amounts, some bisphosphonates can also inhibit normal and ectopic mineralization through a physical-chemical inhibition of crystal growth. In the growing rat the inhibition of resorption is accompanied by an increase in intestinal absorption and an increased balance of calcium. Bisphosphonates also prevent various types of experimental osteoporosis, such as after immobilization, ovariectomy, orchidectomy, administration of corticosteroids, or low calcium diet. The P-C-P bond of the bisphosphonates is completely resistant to enzymatic hydrolysis. The bisphosphonates studied up to now, such as etidronate, clodronate, pamidronate, and alendronate, are absorbed, stored, and excreted unaltered. The intestinal absorption of the bisphosphonates is low, between 1% or less and 10% of the amount ingested. The newer bisphosphonates are at the lower end of the scale. The absorption diminishes when the compounds are given with food, especially in the presence of calcium. Bisphosphonates are rapidly cleared from plasma, 20%-80% being deposited in bone and the remainder excreted in the urine. In bone, they deposit at sites of mineralization as well as under the osteoclasts. In contrast to plasma, the half-life in bone is very long, partially as long as the half-life of the bone in which they are deposited. In humans, bisphosphonates are used successfully in diseases with increased bone turnover, such as Paget's disease, tumoural bone disease, as well as in osteoporosis. Various bisphosphonates, such as alendronate, clodronate, etidronate, ibandronate, pamidronate, and tiludronate, have been investigated in osteoporosis. All inhibit bone loss in postmenopausal women and increase bone mass. Furthermore, bisphosphonates are also effective in preventing bone loss both in corticosteroid-treated and in immobilized patients. The effect on the rate of fractures has recently been proven for alendronate. In humans, the adverse effects depend upon the compound and the amount given. For etidronate, practically the only adverse effect is an inhibition of mineralization. The aminoderivatives induce for a period of 2-3 days a syndrome with pyrexia, which shows a similitude with an acute phase reaction. The more potent compounds can induce gastrointestinal disturbances, sometimes oesophagitis, when given orally. Bisphosphonates are an important addition to the therapeutic possibilities in the prevention and treatment of osteoporosis.

Clodronate improves bone mineral density in post-menopausal breast cancer patients treated with adjuvant antioestrogens

The effect of clodronate on bone mineral density (BMD) was studied in 121 post-menopausal breast cancer women without skeletal metastases. In addition, two antioestrogens, tamoxifen and toremifene, were compared in their action on bone mineral density. Patients were randomized to have an adjuvant antioestrogen treatment either 20 mg of tamoxifen or 60 mg of toremifene daily for 3 years. In addition all patients were randomized to have 1600 mg of oral clodronate daily or to act as control subjects. BMD of the lumbar spine and femoral neck were measured by dual-energy radiographic absorptiometry before therapy and at 1 and 2 years. At 2 years, clodronate with antioestrogens markedly increased BMD in the lumbar spine and femoral neck by 2.9% and 3.7% (P = 0.001 and 0.006 respectively). There were no significant changes in BMD in the patients given antioestrogens only. No significant differences were found between tamoxifen and toremifene on bone mineral density. Clodronate with antioestrogens significantly increased bone mass in the lumbar spine and femoral neck. Both antioestrogens, tamoxifen and toremifene, similarly prevented bone loss in the lumbar spine and femoral neck.

Effects of cyclical etidronate therapy on bone loss in early postmenopausal women who are not undergoing hormonal replacement therapy

This study was carried out to investigate the effectiveness and tolerability of cyclical etidronate therapy in the prevention of bone loss occurring in early postmenopausal women who are not undergoing hormone replacement therapy (HRT). A total of 109 Caucasian women aged 45-60 years were treated with etidronate 400 mg/day or placebo for 14 days followed by calcium supplementation 500 mg/day for 77 days. Ninety-one women completed the 2 years of the study. After 2 years, the estimated difference between the two groups as regards lumbar spine bone mineral density (BMD) was 2.53% (SEM 1.07%; p = 0.01); BMD of the hip and wrist were not significantly different between treatment groups. A clear reduction in bone turnover was obtained as evidenced by a significant decrease in serum alkaline phosphatase level and in urinary N-telopeptide/ creatinine ratio in the etidronate group; the difference between the two groups was -12% +/- 3.2% for serum alkaline phosphatase level (p = 0.019) and -22.9% +/- 13.7% for the urinary N-telopeptide/creatinine ratio (p = 0.047). There was no statistically significant difference between the two groups in terms of the serum osteocalcin levels and urinary hydroxyproline/ creatinine and calcium/creatinine ratios. Etidronate was generally well tolerated and its adverse event profile was similar to that of placebo. The results of this study indicate that cyclic etidronate therapy can prevent trabecular bone loss, with no deleterious effect on cortical bone, in the first 5 years of menopause and that it has a very high safety margin.

Bisphosphonate therapy

The bisphosphonates are long-lived synthetic analogs of pyrophosphate, a natural, short-lived inhibitor of bone. Oral doses share similar qualities (ie, they inhibit bone resorption, poor absorption, and potential gastrointestinal irritants), but each one has a unique spectrum of potency and a probable mechanism of action. The parent compound, etidronate, was first used in multicentered trials for the treatment of primary osteoporosis and showed some success in increasing bone density and perhaps controlling fracture rates. The recently approved drug alendronate is a more potent agent than etidronate, produces a greater increase in bone density, and decreases fractures. Oral and intravenous pamidronate have similar positive effects on bone density. Studies with tiludronate, risedronate, and clodronate show similar promise as therapeutic agents.

Serum N-terminal osteocalcin is a good indicator for estimating responders to hormone replacement therapy in postmenopausal women

To estimate the response to hormone replacement therapy (HRT) by bone metabolic markers, 36 patients with postmenopausal osteoporosis or osteopenia were studied to assess the correlation between percent baseline changes in lumbar bone mineral density (BMD) after 12 months and those in various bone metabolic markers after 3, 6, and 12 months of HRT. All the patients were treated with 0.625 mg of conjugated estrogen and 2.5 mg of medroxyprogesterone per day and continued for 12 months. BMD was significantly increased up to 4.19 +/- 0.87% after 6 months and 4.93 +/- 1.27% after 12 months of HRT (p = 0.0001 by analysis of variance). In accordance with this, changes in the levels of osteocalcin (p = 0.041), alkaline phosphatase (p = 0.0001), N-terminal osteocalcin (p = 0.0001), urinary excretion of pyridinoline/Cr (p = 0.0001), and deoxypyridinoline/Cr (p = 0.0001) were significantly decreased, respectively. Among these bone metabolic markers, only the change in the serum N-terminal osteocalcin at 3 months (r = 0.557, p = 0.0022), at 6 months (r = 0.470, p = 0.0184), and at 12 months (r = 0.545, p = 0.0061) significantly correlated with the change in BMD 12 months after HRT. The elution profiles of immunoreactive osteocalcin-related molecules in serum fractionated by reverse-phase high performance liquid chromatography revealed that the N-terminal fragment as well as the intact osteocalcin molecule decreased after 3 months of HRT. These results demonstrate that N-terminal osteocalcin is a suitable predictor for estimating good responders to HRT in postmenopausal women.

Current and potential future drug treatments for osteoporosis

There has been a major interest in the drug treatment of osteoporosis and an increase in the number of drugs available in most countries. The ideal drug (one which increases or restores bone density and trabecular connectivity) is still not available. However, in patients with relatively preserved trabecular connectivity and moderately reduced bone density, several agents have shown substantial clinical benefit. Oestrogens are still the mainstay of drug treatment, but the risks of breast cancer versus the cardiovascular and skeletal benefits with long term use have to be assessed in the individual. Newer tissue specific oestrogens show some promise in this respect. The bisphosphonates and possibly fluoride are likely to be the major alternatives to oestrogens in the medium term. The newer bisphosphonates, alendronate and in the future risedronate, are likely to supersede etidronate. Calcitriol probably has a limited role, confined to those patients in whom HRT or bisphosphonates are not appropriate. Calcium supplementation, or an increase in dietary intake if deficient, irrespective of which agent is used, is also of benefit. In older patients there is considerable support for using a combination of calcium and vitamin D. Whether combination treatment, for example oestrogens, bisphosphonates, and calcium together, will result in greater efficacy remains to be conclusively shown, but may be an attractive option in younger patients with higher bone turnover. Apart from fluoride, bone formation stimulators are unlikely to have a major role until the next century, although it may be possible to use growth factors as part of an ADFR regimen (A = activate remodelling, D = depress resorption, F = free formation, and R = repeat). This is still an important theoretical approach and needs further work with newer agents to see if increased efficacy can be found. In addition sequential treatment may be necessary in view of the limited time periods over which particular agents, such as intermittent fluoride (four years), have been examined, and this will have to be individually tailored. Other approaches include trying to increase peak bone mineral density, although influencing the young to prevent a disease that may not manifest itself for half a century is daunting.

Clodronate and osteoporosis

Bisphosphonates are widely used in disorders associated with increased resorption of bone, particularly in Paget's disease of bone and the hypercalcaemia of malignancy. Their undoubted efficacy and relatively low toxicity makes them attractive candidates for the management of osteoporosis. The three bisphosphonates widely tested are etidronate, pamidronate and clodronate. Whereas pamidronate can only be given by intravenous infusion, clodronate may be given intravenously or by mouth. Unlike etidronate, even high doses of clodronate do not impair the mineralisation of bone, making it suitable for long-term use in osteoporosis. Clodronate has been shown to inhibit experimentally induced increases in bone resorption and in patients prevents bone loss at the menopause and during immobilisation. Short-term and long-term studies indicate that clodronate appears to stop bone loss at the lumbar spine in patients with vertebral osteoporosis. Long-term studies of the effects at the hip are not yet reported. The effects of clodronate on the frequency of osteoporotic fractures are not yet known and will demand well controlled long-term prospective studies.

Prevention of hip fractures: drug therapy

Drug therapy to prevent hip fractures may be considered for postmenopausal women with low bone mass and elderly people with risk factors for hip fracture. As most hip fractures occur 25 years or more after menopause, drug therapy may have to be prescribed for many years to be effective. A preventative drug should be effective, safe, and without side effects. Estrogen therapy decreases bone loss and hip fracture incident, but the effect wears off when treatment is stopped. The positive effect of estrogens on cardiovascular disease should be balanced against the increased risk of breast cancer with long-term use. The newer bisphosphonates are potent inhibitors of bone resorption and decrease bone loss substantially. Again, the effect may wear off after the drug is stopped. The bisphosphonates appear to be safe, but long-term data are lacking. Calcium and/or vitamin D may prevent bone loss in late postmenopausal women and elderly people. The combination was shown to prevent hip fractures and other peripheral fractures in elderly nursing home residents. No single drug will be used more than 10-15 years. Therefore, a public health strategy should be developed with a logical sequence of drug and nondrug interventions for the successful prevention of hip fractures.

Cyclical intravenous clodronate in postmenopausal osteoporosis: results of a long-term clinical trial

We report the results of long-term cyclical clodronate therapy (200 mg IV infusion every 3 weeks) on 235 women with postmenopausal osteoporosis recruited over 6 years. A retrospective analysis of clinical and instrumental findings in 183 postmenopausal osteoporotic patients was used as control data. Clodronate was well-tolerated and compliance was good. Bone mineral density (BMD) increased significantly and the upward trend persisted for all 6 years of therapy (5.69 +/- 0.184%) vs. controls: -1.47% +/- 0.813%, p <0.0001). The increase in BMD was greater in the 145 patients without vertebral fractures before starting clodronate. From year 3 onward clodronate reduced the incidence of new vertebral fractures. In closed subsets of patients and controls monitored for 3 and 4 years, respectively, the number of patients developing new vertebral fractures fell significantly in the clodronate group (two-sided p value = 0.0671 and p <0.0026, respectively). This trend was more marked in patients who were fracture-free at the beginning of each year. Cyclical clodronate is a safe and effective therapy for established osteoporosis, but clinical trials are necessary to compare its efficacy versus continuous therapy and, as in the case of the other bisphosphonates, to investigate its mechanisms of action in depth.

Role of oral pamidronate in preventing bone loss in postmenopausal women

We have performed a 2-year prospective double-masked study to determine whether the bisphosphonate pamidronate can prevent bone loss in postmenopausal women and its optimal dosage regimen. One hundred and twenty-one such women (mean +/- SD age 57.6 +/- 3.4 years; mean +/- SD time since menopause 7.5 +/- 3.5 years) were randomized to receive either oral pamidronate (300 mg/day) for 4 weeks every 4 months (group A), oral pamidronate (150 mg/day) for 4 weeks every 2 months (group B) or identical placebo capsules (group C). Bone mineral density (BMD) measurements at the lumbar spine and proximal femur were performed at baseline and at 6-month intervals for 2 years using dual-energy X-ray absorptiometry. BMD at the lumbar spine (L2-4) increased significantly in groups A and B after 2 years of treatment (mean +/- SD 2.8 +/- 2.1% and 3.0 +/- 2.9% respectively, both p < 0.001) but decreased in the placebo group (-1.6 +/- 3.1%, p < 0.01). Identical results were seen for BMD at the femoral neck, which increased significantly in groups A and B after 2 years of treatment (1.2 +/- 2.3% and 1.3 +/- 2.9% respectively, both p < 0.05) but decreased in the placebo group (-1.9 +/- 3.9%, p < 0.05). There were significant differences over 2 years between the groups at all anatomical sites (lumbar spine, femoral neck and trochanteric region, all p < 0.001; Ward's triangle, p < 0.01). However, there were no significant differences between groups A and B, suggesting that the two treatment regimens were equally effective in conserving BMD. There were, however, marked differences in tolerability between the two treatment regimens: 13 women (34%) in group A withdrew from the study because of side-effects, but only 5 women (12%) in group B, which was comparable with placebo. These data demonstrate that intermittent oral pamidronate will prevent bone loss from the lumbar spine and proximal femur of postmenopausal women, and that the more frequent but lower dose regimen is well tolerated.