Effects of disodium dichloromethylene diphosphonate on hypercalcemia produced by bone metastases

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.

Bisphosphonates in Oncology: Physiopathologic Bases and Clinical Activity

Osteoclastic activation is the ultimate way of bone resorption in neoplasia, induced by the combined effects of tumor-secreted humoral factors (especially parathyroid hormone-related peptides) and osteoclastic-osteoblastic interaction. Bisphosphonates inhibit the osteoclast activity and reduce bone resorption and are a valuable supportive measure for bone disease of neoplasms. Experimental models also suggest an activity of bisphosphonates against cancer cells. Controlled studies, especially in advanced breast cancer and multiple myeloma, indicate different effectiveness against the distinct skeletal-related events. Intravenous clodronate and, especially, pamidronate and zoledronate are the first-choice drugs for hypercalcemia, and they play a significant role in reducing metastatic bone pain. Their prolonged use delays, without hampering, the progression of bone disease, including the appearance of osteolysis and the occurrence of pathologic fractures. This effect is probably more valuable when bisphosphonates are administered early in the course of the disease. The evidence that adjuvant bisphosphonates improve survival needs to be confirmed in ongoing studies. Although poorly absorbed by the gastrointestinal tract, oral bisphosphonates are effective in preventing and treating cancer-induced osteoporosis in long-living patients with operable breast cancer. At present, there is little hope that newer bisphosphonates are more effective than those currently used.

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.

One-pot and highly regio-selective 1,3-dipole cycloaddition of azomethine ylide generated in situ to tetraethyl vinylidenebisphosphonate (VBP) catalyzed by cerium(iv) oxide

Higly regio-selective heterocyclic bisphosphonates are obtained in moderate yields (30–70%). The structures of the targeted molecules are characterized by NMR (such as COSY, HSQC, and HMBC), IR and MS.

Bisphosphonates: the first 40 years

The first full publications on the biological effects of the diphosphonates, later renamed bisphosphonates, appeared in 1969, so it is timely after 40years to review the history of their development and their impact on clinical medicine. This special issue of BONE contains a series of review articles covering the basic science and clinical aspects of these drugs, written by some of many scientists who have participated in the advances made in this field. The discovery and development of the bisphosphonates (BPs) as a major class of drugs for the treatment of bone diseases has been a fascinating story, and is a paradigm of a successful journey from 'bench to bedside'. Bisphosphonates are chemically stable analogues of inorganic pyrophosphate (PPi), and it was studies on the role of PPi as the body's natural 'water softener' in the control of soft tissue and skeletal mineralisation that led to the need to find inhibitors of calcification that would resist hydrolysis by alkaline phosphatase. The observation that PPi and BPs could not only retard the growth but also the dissolution of hydroxyapatite crystals prompted studies on their ability to inhibit bone resorption. Although PPi was unable to do this, BPs turned out to be remarkably effective inhibitors of bone resorption, both in vitro and in vivo experimental systems, and eventually in humans. As ever more potent BPs were synthesised and studied, it became apparent that physico-chemical effects were insufficient to explain their biological effects, and that cellular actions must be involved. Despite many attempts, it was not until the 1990s that their biochemical actions were elucidated. It is now clear that bisphosphonates inhibit bone resorption by being selectively taken up and adsorbed to mineral surfaces in bone, where they interfere with the action of the bone-resorbing osteoclasts. Bisphosphonates are internalised by osteoclasts and interfere with specific biochemical processes. Bisphosphonates can be classified into at least two groups with different molecular modes of action. The simpler non-nitrogen containing bisphosphonates (such as etidronate and clodronate) can be metabolically incorporated into non-hydrolysable analogues of ATP, which interfere with ATP-dependent intracellular pathways. The more potent, nitrogen-containing bisphosphonates (including pamidronate, alendronate, risedronate, ibandronate and zoledronate) are not metabolised in this way but inhibit key enzymes of the mevalonate/cholesterol biosynthetic pathway. The major enzyme target for bisphosphonates is farnesyl pyrophosphate synthase (FPPS), and the crystal structure elucidated for this enzyme reveals how BPs bind to and inhibit at the active site via their critical N atoms. Inhibition of FPPS prevents the biosynthesis of isoprenoid compounds (notably farnesol and geranylgeraniol) that are required for the post-translational prenylation of small GTP-binding proteins (which are also GTPases) such as rab, rho and rac, which are essential for intracellular signalling events within osteoclasts. The accumulation of the upstream metabolite, isopentenyl pyrophosphate (IPP), as a result of inhibition of FPPS may be responsible for immunomodulatory effects on gamma delta (γδ) T cells, and can also lead to production of another ATP metabolite called ApppI, which has intracellular actions. Effects on other cellular targets, such as osteocytes, may also be important. Over the years many hundreds of BPs have been made, and more than a dozen have been studied in man. As reviewed elsewhere in this issue, bisphosphonates are established as the treatments of choice for various diseases of excessive bone resorption, including Paget's disease of bone, the skeletal complications of malignancy, and osteoporosis. Several of the leading BPs have achieved 'block-buster' status with annual sales in excess of a billion dollars. As a class, BPs share properties in common. However, as with other classes of drugs, there are obvious chemical, biochemical, and pharmacological differences among the various BPs. Each BP has a unique profile in terms of mineral binding and cellular effects that may help to explain potential clinical differences among the BPs. Even though many of the well-established BPs have come or are coming to the end of their patent life, their use as cheaper generic drugs is likely to continue for many years to come. Furthermore in many areas, e.g. in cancer therapy, the way they are used is not yet optimised. New 'designer' BPs continue to be made, and there are several interesting potential applications in other areas of medicine, with unmet medical needs still to be fulfilled. The adventure that began in Davos more than 40 years ago is not yet over.

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.

Clodronate treatment in patients with malignancy-associated hypercalcemia

The possibility of reducing symptomatic hypercalcemia and of maintaining total serum calcium concentrations less than 2.8 mmol/l with clodronate (dichloromethylene bisphosphonate) was evaluated in 28 patients with various types of malignant tumors. Four episodes of hypercalcemic crisis with mean serum calcium concentrations of 4.43 mmol/l were controlled within 4-6 days of intravenous clodronate (4 mg/kg BW/day). This was accompanied by a moderate increase in serum creatinine values which, however, returned to pretreatment levels after therapy withdrawal in all but one case. Oral clodronate successfully reduced a mean serum calcium concentration of 3.16 mmol/l in 22 out of 25 patients after 3-12 days (800-3,200 mg/day). After reversal of the hypercalcemias oral clodronate controlled the serum calcium concentration for up to 42 weeks in six out of 15 patients After discontinuation of initial therapy five of seven recurrent hypercalcemias were successfully treated with oral or intravenous clodronate. Hypocalcemia and subjective side-effects were uncommon. It is concluded that clodronate is a valuable clinical tool in the management of patients with malignancy-associated hypercalcemia.

Systematic review of bisphosphonates for hypercalcaemia of malignancy

BACKGROUND

Bisphosphonates are the treatment of choice for hypercalcaemia of malignancy (HCM) but there is no consensus regarding which drug or dose should be given. We designed a systematic review to investigate the efficacy of bisphosphonates in the treatment of HCM.

METHODS

We identified randomized controlled trials (RCTs) by searching electronic databases, scanning of reference lists, and consultation with experts and pharmaceutical companies. Foreign papers were translated. Inclusion criteria were RCTs, confirmed malignant disease and measurement of serum calcium (ionized or corrected for albumin) postrehydration. The primary outcome was number of patients achieving normocalcaemia. Secondary outcomes were time to normocalcaemia, time to relapse and toxicity.

RESULTS

Twenty-seven papers and two abstracts, using intravenous bisphosphonates, fulfilled the inclusion criteria. Data from 26 studies were used in analyses. Due to the heterogeneity of studies, meta-analysis could not be performed. Pamidronate was more effective than placebo, mithramycin, etidronate (7.5 mg/kg) and low-dose clodronate (600 mg), but equal to higher dose clodronate (1500 mg). Clodronate and etidronate were superior to placebo; incadronate was superior to elcatonin; gallium nitrate was superior to etidronate. No difference was seen between alendronate and clodronate. Three dose finding studies showed no difference between 30-90 mg of pamidronate, but one well designed study showed increasing efficacy with increasing dose. Studies using increasing doses of ibandronate (0.6-4 mg), alendronate (2.5-15 mg), and incadronate (2.5-10mg), showed a dose response. Duration of administration of pamidronate did not affect efficacy (six studies).

CONCLUSION

Bisphosphonates normalize calcium in >70% patients with minimal side effects. Aminobisphosphonates are most effective at maintaining normocalcaemia and should be given in high dose irrespective of baseline serum calcium.

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.

Bisphosphonates for the relief of pain secondary to bone metastases

BACKGROUND

Bisphosphonates form part of standard therapy for hypercalcemia and the prevention of skeletal events in some cancers. However, the role of bisphosphonates in pain relief for bony metastases remains uncertain.

OBJECTIVES

To determine the effectiveness of bisphosphonates for the relief of pain from bone metastases.

SEARCH STRATEGY

MEDLINE (1966-1999), EMBASE (1980-1999), CancerLit (1966-1999), the Cochrane library (Issue 1, 2000) and the Oxford Pain Database were searched using the strategy devised by the Cochrane Pain, Palliative and Supportive Care Group with additional terms 'diphosphonate', 'bisphosphonate', 'multiple myeloma' and 'bone neoplasms'. (Last search: January 2000).

SELECTION CRITERIA

Randomized trials of bisphosphonates compared with open, blinded, or different doses/types of bisphosphonates in cancer patients were included where pain and/or analgesic consumption were outcome measures. Studies where pain was reported only by observers were excluded.

DATA COLLECTION AND ANALYSIS

Article eligibility, quality assessment and data extraction were undertaken by both reviewers. The proportions of patients with pain relief at 4, 8 and 12 weeks were assessed. The proportion of patients with analgesic reduction, the mean pain score, mean analgesic consumption, adverse drug reactions, and quality of life data were compared as secondary outcomes.

MAIN RESULTS

Thirty randomized controlled studies (21 blinded, four open and five active control) with a total of 3682 subjects were included. For each outcome, there were few studies with available data. For the proportion of patients with pain relief (eight studies) pooled data showed benefits for the treatment group, with an NNT at 4 weeks of 11[95% CI 6-36] and at 12 weeks of 7 [95% CI 5-12]. In terms of adverse drug reactions, the NNH was 16 [95% CI 12-27] for discontinuation of therapy. Nausea and vomiting were reported in 24 studies with a non-significant trend for greater risk in the treatment group. One study showed a small improvement in quality of life for the treatment group at 4 weeks. The small number of studies in each subgroup with relevant data limited our ability to explore the most effective bisphosphonates and their relative effectiveness for different primary neoplasms.

REVIEWER'S CONCLUSIONS

There is evidence to support the effectiveness of bisphosphonates in providing some pain relief for bone metastases. There is insufficient evidence to recommend bisphosphonates for immediate effect; as first line therapy; to define the most effective bisphosphonates or their relative effectiveness for different primary neoplasms. Bisphosphonates should be considered where analgesics and/or radiotherapy are inadequate for the management of painful bone metastases.

Effects of bisphosphonate (pamidronate) on bone resorption resulting from metastasis of a squamous cell carcinoma: report of an autopsy case and evaluation of bone resorbing activity in an experimental animal model

PURPOSE

This study evaluated the ability of bisphosphonate to prevent bone resorption induced by metastatic tumor cells.

MATERIALS AND METHODS

Autopsy specimens of a bone metastasis from a woman with a primary squamous cell carcinoma of the tongue who developed multiple osteolytic lesions and hypercalcemia and was treated with pamidronate were studied histologically, histochemically, and ultrastructurally. In an animal experiment, cultured tumor cells (1 x 10(5)) obtained from a metastatic submandibular lymph node in the same patient were injected in the left ventricle of nude mice, and a resulting metastatic bone lesion was studied histologically and histochemically.

RESULTS

In the autopsy specimens, despite the presence of many resorption lacunae on bone surface, only a few small tartrate-resistant acid phosphatase (TRAPase)-positive cells were observed, and most of them were stained weakly and detached from the bone surface. In the animal experiment, 1 of 10 animals (10%) formed osteolytic bone metastasis, and many TRAPase-positive cells were observed histochemically.

CONCLUSIONS

Biphosphonate inhibits bone resorption induced by tumor, possibly by decreasing the number of osteoclasts and inhibiting their function.

Inhibitory effects of bisphosphonate (YM175) on bone resorption induced by a metastatic bone tumor

The effects of a third-generation bisphosphonate, YM175 (disodium dihydrogen (cycloheptylamino)-methylene-1,1-bisphosphonate), on bone resorption induced by a metastatic human melanoma cell line (A375) were investigated morphologically using an experimental model of bone metastases in nude mice. An injection of A375 in the left cardiac ventricle produced multiple osteolytic lesions. Then, 4 weeks after the cell injection, we administrated YM175 (1 mg/kg) intravenously once and sacrificed the animals 3 days later. On histochemical observation, there was a layer of stromal cells with numerous mononuclear and multinucleated tartrate-resistant acid phosphatase (TRAPase)-positive cells in the untreated control group. In contrast, this layer was extensively reduced in most areas, and only a few TRAPase-positive cells were seen around tumor nests and on the bone surface in the experimental group. Most of the TRAPase-positive cells were stained only weakly and/or homogeneously, and there was little evidence of cell polarity. Some of them were vacuolated. Ultrastructurally, they were round and devoid of ruffled borders and clear zones. The findings suggest that YM175 decreases the number and activity of osteoclasts. In addition, a few showed the morphology of cell death, which seemed to be one of the reasons leading to the decrease of osteoclasts. There was no substantial change in the morphological relationships or ultrastructure of osteoclast precursor cells, stromal cells, extracellular matrices, and tumor cells between the experimental and the control groups. In the experimental group, the distribution of extracellular matrices (heparan sulfate proteoglycan and fibronectin) was less conspicuous, but the localization of osteotropic cytokines (interleukin-6 and prostaglandin E2) was essentially similar to that of the control group. The cause leading to the decrease of osteoclast precursor cells remains to be clarified. In conclusion, YM175 inhibits bone resorption induced by tumor, by decreasing the activity of mature osteoclasts and possibly affecting the production of osteoclast precursor cells.

The effect of alendronate on renal tubular reabsorption of phosphate

We report the effects of alendronate on phosphate homeostasis in two patients. In a woman with postmenopausal osteoporosis, the infusion of alendronate (7.5 mg intravenously daily for 4 consecutive days) was not associated with secondary hyperparathyroidism despite a reduction in serum calcium. This was associated with a rise in serum phosphate and TmP/GFR. This response contrasted with those observed in 14 other patients with osteoporosis, in whom PTH rose significantly following the infusion of alendronate in association with a significant fall in serum phosphate and TmP/GFR. The second patient, a woman with Paget's disease, was treated with intravenous alendronate (10 mg daily for 5 consecutive days) on two occasions for relapse of disease activity. On the first occasion there was a 150% rise in serum PTH associated with a fall in serum phosphate and TmP/GFR. On the second occasion, when the rise in serum PTH was less marked, there was a rise in serum phosphate and TmP/GFR. We conclude that alendronate may increase renal tubular reabsorption of phosphate, but that this effect is usually offset by secondary hyperparathyroidism.

Clodronate. A review of its pharmacological properties and therapeutic efficacy in resorptive bone disease

Clodronate (clodronic acid, dichloromethylene bisphosphonate) is a bisphosphonate which has demonstrated efficacy in patients with a variety of diseases of enhanced bone resorption including Paget's disease, hypercalcaemia of malignancy and osteolytic bone metastases. In addition, early reports demonstrating potential efficacy of clodronate in the treatment of osteoporosis suggest a possible role in this debilitating disease. Short term intravenous administration (usually 300 mg/day for 5 days) or longer courses of oral clodronate (usually 1600 mg/day for 6 months) effectively reduced bone pain and/or improved mobility in most patients with Paget's disease, and these effects persisted for up to 12 months after discontinuing clodronate. When administered intravenously (300 mg/day for up to 12 days) to patients with malignant hypercalcaemia, serum calcium levels declined significantly within 2 days of starting treatment and approximately 70 to 95% of patients became normocalcaemic. While there is less experience with oral administration, clodronate (800 to 3200 mg/day) achieved normocalcaemia in the majority of patients, usually within 1 week, and serum calcium levels remained significantly reduced from baseline for up to 6 months with continued treatment. Clodronate is clearly superior to placebo and, based on a retrospective analysis, appears to produce greater and more sustained reductions in serum calcium levels than calcitonin in patients with malignant hypercalcaemia. The few available prospective comparative trials showed that clodronate is at least as effective as etidronate, but comparisons with alendronate and pamidronate produced results of questionable clinical relevance because of low bisphosphonate dosages used in these trials. Nevertheless, single intravenous doses of clodronate 600 mg or alendronate 7.5 mg (both agents repeated on day 3 if necessary) were comparable in efficacy, whereas a single intravenous dose of pamidronate 30 mg was more effective than a single intravenous dose of clodronate 600 mg. Normocalcaemic patients with osteolytic bone metastases due to advanced breast cancer experienced significant reductions in the number of episodes of hypercalcaemia and terminal hypercalcaemia, incidence of vertebral fractures and overall rate of morbid events, including the need for radiotherapy to treat bone-related pain, following treatment with clodronate 1600 mg/day for 3 years in a large placebo-controlled study. A similar large placebo-controlled trial in patients with multiple myeloma demonstrated that clodronate 2400 mg/day orally for 2 years significantly reduced progression of osteolytic bone lesions. Follow-up data from clinical trials revealed that the effects on development of fractures and hypercalcaemia persisted for at least 12 months after the drug was discontinued.(ABSTRACT TRUNCATED AT 400 WORDS)

Drugs used in the treatment of metabolic bone disease. Clinical pharmacology and therapeutic use

Osteoporosis is the most important metabolic bone disease and places an increasing burden on the healthcare system. The condition can be prevented by the early introduction of hormone replacement therapy. The role of bisphosphonates in achieving the same result is being actively explored. The attraction of preventing bone loss is that it preserves the micro-architecture of bone, and therefore its mechanical integrity. The great problem of treating the established condition is that substantial bone loss is accompanied by architectural disintegration. Replacing lost bone may not necessarily restore mechanical integrity and protect against fractures. The management of Paget's disease has been quite revolutionised by the introduction of the bisphosphonates. The condition is a result of a primary increase in osteoclastic bone resorption which can be corrected by bisphosphonates, with considerable symptomatic improvement. The increasing potency and safety margin of the newer agents has meant that the threshold for treatment has fallen. There is now potential for long term control of bone turnover with the hope of preventing late complications. Hypercalcaemia of malignancy is usually the result of both increased bone destruction and decreased urinary calcium excretion. These two components of hypercalcaemia demand different approaches to management. The general availability of an ever-expanding range of increasingly potent bisphosphonates has resulted in a dramatic improvement in the treatment of increased bone resorption associated with malignancy. Many types of tumour, either directly or indirectly, compromise the ability of the kidney to eliminate a calcium load derived from increased bone destruction. Calcitonin is the only agent which is currently available to counter this process.

Comparative effects of clodronate and calcitonin on bone in metastatic breast cancer: a histomorphometric study

We studied the effects of long-term treatment with clodronate, calcitonin or placebo on bone in 36 normocalcaemic women with osteolytic metastases due to breast cancer. Clodronate (1.6 g daily given to 12 patients) induced a significant decrease in osteoclast surface and osteoclast number, and a significant fall in serum calcium and urinary excretion of calcium and hydroxyproline, an effect not noted after treatment with calcitonin (100 U in 12 patients) or in 12 placebo-treated patients. Treatment with clodronate did not abnormally suppress bone turnover nor impair mineralisation, as measured by bone formation and mineral apposition rates.

Metabolism of halogenated bisphosphonates by the cellular slime mould Dictyostelium discoideum

Methylenebisphosphonate and its monofluoro-, difluoro- and dichloro- derivatives inhibited growth of amoebae of Dictyostelium discoideum. Dichloromethylenebisphosphonate was the most potent inhibitor of amoebal growth whereas difluoromethylenebisphosphonate was the least potent inhibitor. Each of the bisphosphonates was taken up by the amoebae and incorporated into the corresponding beta, gamma-methylene analogue of adenosine triphosphate. Two of the bisphosphonates were also incorporated into the corresponding analogues of diadenosyl tetraphosphate. No correlation was found between the ability of the bisphosphonates to inhibit amoebal growth and the extent to which they were metabolised.

Randomised, placebo-controlled multicentre trial of clodronate in multiple myeloma. Finnish Leukaemia Group

Osteolytic lesions and pathological fractures are common in multiple myeloma. Because clodronate inhibits osteoclastic resorption, we did a randomised, controlled trial in 350 patients from 23 hospitals. All patients received standard melphalan-prednisolone, and were randomised to receive clodronate 2.4 g daily or placebo for 24 months. The proportion of patients with progression of osteolytic bone lesions was twice as high in the placebo group (n = 168 at baseline) than in the clodronate group (n = 168 at baseline) in an intention-to-treat analysis (24 vs 12%, p = 0.026). Progression of vertebral fractures was lower in the clodronate group, but the difference was not significant (30 vs 40%). Serum calcium and urinary calcium excretion decreased significantly in both groups, but the changes were greater in the clodronate group. The percentage of patients feeling no pain increased more in the clodronate group (from 24 to 54%, p < 0.001) than in the placebo group (from 29 to 44%, p < 0.01). Side-effects were similar in both groups. We conclude that clodronate is an effective and safe adjunct in the management of multiple myeloma. The drug delays osteolytic bone lesions, reduces the degree of hypercalcaemia and hypercalciuria, and decreases pain.

Medical management of hypercalcaemia

1. Hypercalcaemia is a common disorder, which frequently requires specific treatment either to control symptoms, or to prevent the development of irreversible organ damage or death. Although the best and most effective way of controlling hypercalcaemia in the long-term is to treat the underlying cause, medical antihypercalcaemic therapy is often required in clinical practice, either as a holding measure, or because the primary disease cannot itself be treated. 2. The mainstays of medical antihypercalcaemic therapy are firstly, to promote calcium excretion by the kidney by restoring extracellular volume with intravenous saline and secondly, to administer pharmacological agents which inhibit bone resorption. Measures which seek to reduce intestinal calcium absorption are seldom effective. 3. Intravenous bisphosphonates are the treatment of first choice for the initial management of hypercalcaemia, followed by continued oral, or repeated intravenous bisphosphonates to prevent relapse. These drugs have a relatively slow onset of action (1-3 days) but have potent and sustained inhibitory effects on bone resorption, resulting in a long duration of action (12-30 days). 4. Of the other agents available, calcitonin has an important place in the management of severe hypercalcaemia where a rapid effect is desirable; calcitonin is best used in conjunction with a bisphosphonate however, because of its short duration of action. Intravenous phosphate also has a place in the emergency management of severe hypercalcaemia, but is probably best reserved for patients in whom other less toxic therapies have failed. Corticosteroids are generally ineffective except in certain specific instances and are best avoided in the routine treatment of undiagnosed hypercalcaemia.

Longitudinal effect of tiludronate on bone mineral density, resonant frequency, and strength in monkeys

The effect of Tiludronate on bone was studied in 72 growing monkeys (Papio papio), 36 males and 36 females, aged 4-7 years. They were randomly allocated into four groups (18 animals per group, 9 males and 9 females): group I, controls; group II, 10 mg/kg/day; group III, 20 mg/kg/day; and group IV, 40 mg/kg/day of Tiludronate. A total of 12 animals (6 males and 6 females) in each group were sacrificed at the end of treatment (1 year) and 6 animals (3 males and 3 females) per group 1 year later. Bone mineral density (BMD) was measured by dual-photon absorptiometry. Biomechanical properties were evaluated by an impact torsion test and by resonant frequency analysis. Bone mineral measurements indicated that at the end of 1 year of treatment BMD was significantly higher, especially at the distal epiphysis of the radius, than in controls. No significant differences between groups were found in BMD 1 year after stopping treatment. Biomechanical analyses indicated that torsional stiffness increased after treatment. No differences between groups were found 1 year after stopping treatment. Results of resonant frequencies indicated an increased calculated transversal stiffness after treatment and 1 year later and an increased buckling strength 1 year after stopping treatment. In conclusion, the results on the effect of Tiludronate in growing monkeys indicate a profound effect of this drug on bone density and biomechanical properties. The biomechanical results indicate that this drug is safe, with conservation of bone strength despite a change in intrinsic mechanical properties of the bone.

Bisphosphonates. Pharmacology and use in the treatment of tumour-induced hypercalcaemic and metastatic bone disease

The geminal bisphosphonates are a new class of drugs characterised by a P-C-P bond. Consequently, they are analogues of pyrophosphate, but are resistant to chemical and enzymatic hydrolysis. The bisphosphonates bind strongly to hydroxyapatite crystals and inhibit their formation and dissolution. This physicochemical effect leads in vivo to the prevention of soft tissue calcification and, in some instances, inhibition of normal calcification. The main effect is to inhibit bone resorption, but in contrast to the effect on mineralisation, the mechanism involved is cellular. These various effects vary greatly according to the structure of the individual bisphosphonate. The half-life of circulating bisphosphonates is very brief, in the order of minutes to hours. 20% to 50% of a given dose is taken up by the skeleton, the rest being excreted in the urine. The half-life in bone is far longer and depends upon the turnover rate of the skeleton itself. Bisphosphonates are very well tolerated; the relatively few adverse events that have been associated with their use are specific for each compound. Bisphosphonates have been used to treat various clinical conditions, namely ectopic calcification, ectopic bone formation, Paget's disease, osteoporosis and increased osteolysis of malignant origin. The three compounds commercially available for use in tumour-induced bone disease are in order of increasing potency, etidronate, clodronate and pamidronate. Most data have been obtained with the latter two agents. By inhibiting bone resorption, they correct hypercalcaemia and hypercalciuria, reduce pain, the occurrence of fractures, as well as the development of new osteolytic lesions, and in consequence improve the quality of life. In view of these actions, of their excellent tolerability and of the fact that they are active for relatively long periods, these compounds are, after rehydration, the drugs of choice in tumour-induced bone disease and an excellent auxiliary to the drugs used in oncology.

Inhibition by a new bisphosphonate (AHBuBP) of bone resorption induced by the MBT-2 tumor of mice

A new bisphosphonate, 4-amino-1-hydroxybuthylidene-1,1-bisphosphonate (AHBuBP), was compared with 3-amino-1-hydroxypropylidene-1,1-bisphosphonate (AHPrBP) and 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) in terms of its effect on tumor-induced osteolysis using a bladder tumor in mice (MBT-2). Tumor cells were inoculated subcutaneously (SC) over the calvaria in mice, resulting in a local tumor causing fragmentation of the bone. The tumor-induced osteolysis associated with osteoclasts proliferation was accompanied with reactive new bone formation. This osteolysis was evaluated by measuring the increased area of bone resorption in reduced opacity to radiograph and histologic study. The results showed the following sequence of potency: AHBuBP greater than AHPrBP = HEBP. This inhibition was obtained with no apparent effect on the growth of the MBT-2 tumor. The authors conclude that AHBuBP appears to be an interesting new bisphosphonate with possible clinical application.

Effects of amino-butylidene diphosphonate in hypercalcemia due to malignancy

We studied the effect of a single 5 mg intravenous infusion of amino-butylidene diphosphonate (ABDP) in nine patients with hypercalcemia of malignancy, in whom serum calcium values were stable or rising after intravascular volume expansion. Serum calcium fell progressively in all patients and in seven reached the normal reference range by day 6 (p less than 0.001). The decrease in serum calcium was associated with a decrease in the fasting urinary calcium/creatinine ratio (p less than 0.05). Hypercalcemia recurred in seven of the patients by day 12, but two patients remained normocalcemic for 21 days. We conclude that ABDP is a highly potent diphosphonate and that a single intravenous infusion is capable of inhibiting tumour-mediated bone resorption for several days.

Treatment of bone metastases from breast cancer and myeloma with pamidronate

28 patients with progressing painful bone metastases (18 breast cancer, 9 myeloma and 1 low grade lymphoma) received pamidronate 60 mg by 24 h continuous infusion for at least 2 courses (range 2-12). In patients urinary calcium and hydroxyproline excretion significantly decreased in relation to diminution of bone resorption. 9 of 18 breast cancer patients and 8 of 9 evaluable patients with myeloma had symptomatic improvement. Sclerotic areas of previously lytic lesions appeared in 8 breast cancer patients and in 1 myeloma patient. Transient fever developed in 1 patient and local phlebitis in 2. Among the 28 patients, 15 did not receive any anticancer treatment or have any change of the anticancer therapy during pamidronate administration. Of 7 with breast cancer, 4 had an improvement of symptoms and 4 sclerosis on radiographs. Impressive control of symptoms was the major feature of 8 myeloma patients, but only 1 had radiographic sclerosis.

Treatment of hypercalcaemia of malignancy with clodronate

The bisphosphonate clodronate has been widely used in the treatment of hypercalcaemia and osteolytic bone metastases. It can normalize plasma calcium in most hypercalcaemic, rehydrated cancer patients when increased bone resorption is the prevailing disturbance of calcium metabolism. When given intravenously either as a single infusion or as repeated daily administrations, serum calcium levels fall to normal 3-5 days after the onset of therapy. Long-term maintenance treatment must be adjusted individually since relapse appears to depend upon the tumour type, the degree of malignancy and any anticancer therapy. In patients in whom increased tubular calcium reabsorption is the prevailing disturbance of calcium metabolism, the effect of clodronate on plasma calcium is incomplete, despite the normalization of bone resorption. This type of therapeutic response can be reproduced experimentally in bisphosphonate-treated animals receiving a constant infusion of parathyroid hormone-related peptide, a peptide isolated from various tumour types including lung, kidney, breast and neuroendocrine tumour of the pancreas. In patients having a good response to clodronate, the fall in plasma calcium is accompanied by an increase in the calcium-regulating hormones, parathyroid hormone and 1,25-dihydroxyvitamin D3. This homeostatic response probably explains why hypocalcaemia occurs rarely in clodronate-treated patients. No serious side-effects of treatment have been reported. Clodronate appears to be a safe and effective treatment for the hypercalcaemia of malignancy, where increased bone resorption is the major mechanism disturbing the homeostasis of extracellular calcium.

Regulation of calcium-parathyroid hormone feedback in primary hyperparathyroidism: effects of bisphosphonate treatment

Dichloromethylene bisphosphonate (C12MBP), a powerful inhibitor of bone resorption, was administered to 27 patients with primary hyperparathyroidism. It was given by either intravenous infusion (six patients, 500-100 mg day), or by intramuscular injection (six patients, 100-200 mg/day) or by mouth (15 patients, 1600-2400 mg/day) for 20-180 days. Sustained suppression of bone resorption was observed in all patients, as judged by a fall in the urinary hydroxyproline excretion. In contrast, the hypocalcaemic effect was inconsistent and short-lived, particularly in the patients without overt bone disease. The fall in serum calcium seemed largely to be due to a transient dissociation between bone resorption and bone formation and was associated with increases in circulating parathyroid hormone (PTH). In ten patients given the bisphosphonate orally for 6 months, serum calcium was unchanged but serum PTH was significantly raised. These results suggest that C12MBP may be of use for short-term correction of severe hypercalcaemia due to hyperparathyroidism, particularly in the patients with overt bone disease. However, its long-term use should not be recommended because of increased PTH secretion.

Fast (4-h) or slow (24-h) infusions of pamidronate disodium (aminohydroxypropylidene diphosphonate (APD)) as single shot treatment of hypercalcaemia

Twenty-five patients with hypercalcaemia (ionised calcium, 1.57 +/- 0.04 mM; total calcium, 3.33 +/- 0.06 mM) due to malignancy were randomised to receive pamidronate (1 mg/kg body wt.) by infusion over 4 h (12 patients) or 24 h (13 patients). Forced saline diuresis was not utilised. Two patients died within 24 h and were not included in the analysis. Both groups combined (n = 23) showed a decrease in ionised calcium to 1.44 +/- 0.04 mM by 2 days (P less than 0.05 vs. day 0). By 4 days there had been a further fall to 1.27 +/- 0.05 mM (P less than 0.05 vs. day 2) and 7 days after treatment ionised calcium was 1.19 +/- 0.05 mM (P less than 0.05 vs. day 4). Total calcium declined from 3.33 +/- 0.06 to 2.65 +/- 0.11 mM over 7 days (P less than 0.001). Separate analyses of the two groups showed that the fast (4-h) infusion led to an earlier reduction in calcium than did the 24-h infusion (P less than 0.02), although after 7 days there was little difference between the two groups (4 h, 1.18 +/- 0.09 mM; 24 h, 1.23 +/- 0.06 mM, n.s.). Hypercalcaemic symptoms (analogue rating scale) improved between each of the time intervals 0, 4 and 7 days (P less than 0.05) and did not differ between the two groups. We recommend a single 4-h infusion of pamidronate (1 mg/kg) as primary treatment for malignancy-induced hypercalcaemia.

Clodronate in hypercalcemia of malignancy

Of the many compounds belonging to the diphosphonate family, clodronate has been widely used in hypercalcemia and osteolysis of malignancy. All published reports indicate that clodronate can normalize plasma calcium in the majority of hypercalcemic, rehydrated cancer patients in whom increased bone resorption is the prevailing disturbed calcium flux. In these patients, clodronate, given intravenously either as a single infusion or as repeated daily administrations, can normalize serum calcium, usually 3-5 days after the onset of therapy. In these good responders, long-term maintenance treatment should be individually adjusted since relapse appears to depend upon the type of tumor, the extent of malignancy and the administration of anticancer therapy. In a subset of well-rehydrated hypercalcemic patients in whom increased tubular calcium reabsorption represents the prevailing disturbed calcium flux, the acute effect of clodronate on plasma calcium is incomplete, despite the normalization of bone resorption. This type of therapeutic response can be experimentally reproduced in diphosphonate-treated animals receiving a constant infusion of parathyroid hormone-related peptide, a peptide isolated from lung, kidney and breast carcinomas. This indicates that, in addition to antiosteolytic drugs, such as clodronate, patients with hypercalcemia of malignancy would benefit from the development of agents that can selectively reduce the renal tubular reabsorption of calcium. In patients displaying a good response to clodronate, the fall in plasma calcium is accompanied by an increase in the calcium-regulating hormones, parathyroid hormone and 1,25-dihydroxyvitamin D3. This homeostatic reaction probably explains why hypocalcemia rarely occurs in clodronate-treated patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of clodronate and calcitonin in hypercalcemia due to malignancy

Increased bone resorption and increased renal tubular reabsorption of calcium are involved in the pathogenesis of hypercalcemia of malignancy. Clodronate and calcitonin inhibit bone resorption and have been used as therapy for malignancy-associated hypercalcemia. Both drugs induce significant reductions of serum calcium but the decrease is greater with clodronate, particularly when given intravenously. While the response to calcitonin generally is of short duration, clodronate can maintain normal serum calcium values over several weeks when oral administered. Thus, from the clinical point of view clodronate is a very useful adjunct to the available therapy.

Bisphosphonates: a new class of drugs in diseases of bone and calcium metabolism

The geminal bisphosphonates are characterized by a PCP bond and are therefore analogs of pyrophosphate. They bind strongly to hydroxyapatite crystals and in vitro inhibit both crystal formation and dissolution. In vivo they inhibit soft tissue calcification and when given in large amounts also normal calcification. This effect is due to the inhibition of calcium phosphate crystal growth. Furthermore, the bisphosphonates are very potent inhibitors of bone resorption. The mechanism(s) of action is not yet known but is likely to be at a cellular level. The extent of the biological activity of each compound depends on the specific chemical structure, so that each individual bisphosphonate must be considered as a separate compound. The only common characteristic is the PCP group, which gives the compound its high affinity to bone. The individual effects, however, are determined by the side groups on the carbon atom. This opens interesting possibilities for the development of new compounds. No bisphosphonate analyzed so far can be degraded in vivo; all are either deposited in the skeleton, where they remain for years until the bone is destroyed, or are excreted in the urine. The high affinity for bone explains the specificity of the compounds for bone and the fact that they have relatively few nonosseous effects. Bisphosphonates are used in man to inhibit ectopic calcification, including dental tartar and ectopic ossification. Furthermore, they are used to inhibit bone resorption, especially in diseases such as Paget's disease and tumoral osteolysis. Finally, when linked to 99nTc, bisphosphonates are employed as bone scanning agents.

Current management of malignant hypercalcaemia

The pathogenic mechanisms causing malignant hypercalcaemia are primarily increased bone calcium mobilisation and renal calcium retention. In some reticuloendothelial malignancies, enhanced intestinal calcium absorption may also play a role. Malignant hypercalcaemia is a life-threatening condition, and there are many patients with malignancy in whom suppression of this complication is most desirable. In such cases, successful management of the hypercalcaemia will enable the overall treatment aims, such as tumour removal or ablation, to be achieved. Acute treatment involves the rapid lowering of serum calcium from potentially fatal concentrations, and comprises the use of intravenous rehydration, calcitonin and diphosphonates. In the longer term, other measures may be introduced to maintain and control the calcium concentration while specific antitumour therapy is instituted.

Bone and renal components in hypercalcemia of malignancy and responses to a single infusion of clodronate

Increased bone resorption (BR) and increased renal tubular reabsorption of calcium (TRCa) may both be involved in the pathogenesis of hypercalcemia of malignancy (HM). We have evaluated the relative importance of these two mechanisms in 33 patients with HM after extracellular volume expansion and after single infusion of clodronate (C12MDP: 500 mg iv over 8 h). The fasting urine Ca/creatinine ratio was taken as an index of BR (BRI). An index of TRCa was calculated (TRCaI) from a nomogram based on the relationship between urine Ca excretion per unit of glomerular filtration rate and plasma Ca (PCa). Mean (+/- SEM) PCa fell from 3.29 +/- 0.07 to 2.69 +/- 0.05 mmol/l three days after C12MDP (n = 33, p less than 0.001), a response similar to that obtained with repeated daily iv injections of 500 to 1000 mg C12MDP. The pathogenesis of hypercalcemia varied according to the type of neoplasm. BRI was the highest in multiple myeloma and breast tumors. TRCaI was markedly increased in squamous-cells lung, bladder, kidney and liver carcinomas, reaching levels observed in primary hyperparathyroidism. TRCaI was normal in most cases of multiple myeloma. Breast tumors appeared to be heterogeneous with respect to TRCaI. The fall in PCa in response to a single infusion of C12MDP was usually most marked in cancer patients with elevated BRI and normal TRCaI. It was very modest in patients with high TRCaI and slightly elevated BRI. In conclusion, this study confirms that stimulation of bone resorption is not the only mechanism of the maintenance of hypercalcemia of malignancy.(ABSTRACT TRUNCATED AT 250 WORDS)

A model of localized osteolysis induced by the MBT-2 tumor in mice and its responsiveness to etidronate disodium

A new experimental method to test the effect of drugs on tumor-induced osteolysis using a bladder tumor in mice has been designed. The method consisted of inoculating MBT-2 tumor cells s.c. over the calvaria in mice, resulting in a local tumor causing fragmentation of the bone. This was accompanied by adjacent osteoplastic changes, which were evaluated by X-ray and histological examination. Etidronate disodium (EHDP), a diphosphonate derivative, at a dose of 3 mg/kg to 30 mg/kg s.c. protected the bone by decreasing the extent of osteolysis as judged by the same criteria. Therapy with EHDP prolonged the survival period. This inhibition was obtained with no apparent effect on the growth of the MBT-2 tumor.

Intravenous aminopropylidene bisphosphonate (APD) in the treatment of Paget's bone disease

We studied the effect of the intravenous administration of the bisphosphonate APD in 9 patients with Paget's bone disease. The medication was given in a daily dose of 25 mg for 7 days in 0.9% saline infusion over 2 hours. At the end of treatment a significant fall of serum calcium and phosphate was observed. The urinary excretion of calcium decreased markedly and the serum levels of the mid-molecule PTH fragment increased from (mean +/- SE) 85 +/- 11 to 122 +/- 16 pg/ml (p less than 0.05). A marked and rapid decline in the hydroxyprolinuria was observed from 297 +/- 61 mg/24 h to 194 +/- 51 mg/24 h (p less than 0.01); meanwhile the serum alkaline phosphatase decreased from 102 +/- 22 to 84 +/- 21 KAU (p less than 0.05). The effect of ADP on suppression of hydroxyprolinuria varied markedly from +1 to -81% and was negatively related to the basal hydroxyprolinuria (r = -0.90; p less than 0.001). The duration of the bone turnover suppression was short. A relapse greater than 30% in hydroxyprolinuria was observed in 6 of 8 patients 2 to 3 months after APD withdrawal. The short-term intravenous administration of ADP is a useful means to rapidly suppress the activity of Paget's bone disease. However, further studies should determine the optimum dose, the length of treatment, and the need to associate oral therapy to induce a prolonged remission.

Role of bone and kidney in tumor-induced hypercalcemia and its treatment with bisphosphonate and sodium chloride

The efficacy of intravenous aminohydroxypropylidene bisphosphonate as treatment for the hypercalcemia of malignancy was examined in a phase II multicenter study in 132 patients with a large variety of primary tumors. This provided an opportunity for an analysis of the separate influences of bone resorption and renal calcium handling on the genesis and maintenance of hypercalcemia. The results demonstrated that increased bone resorption is the major contributory factor and that inhibition with bisphosphonate normalizes the serum calcium concentration within five days in more than 90 percent of patients. Hypercalcemia is sustained by an inability of the kidney to deal efficiently with a chronically increased calcium load. This is influenced by the requirements of volume regulation in the presence of a sodium diuretic effect of hypercalcemia and is very sensitive to induced variations of sodium load. In addition, in a minority of patients, direct renal actions of tumor-derived humoral factors adversely reduce the ability to excrete calcium. For optimal treatment of tumor-induced hypercalcemia, bisphosphonate treatment should be combined with intravenous administration of saline solution.

Effectiveness of salmon calcitonin administered as suppositories in tumor-induced hypercalcemia

Although calcitonin is a natural, nontoxic, and rapid inhibitor of bone resorption, its use in the treatment of hypercalcemia is limited because of its transient efficacy and the need for repeated parenteral administration. In normal subjects, suppositories of calcitonin have been shown to be biologically active. Peak plasma concentrations of salmon calcitonin after rectal administration in six normal subjects were similar to those measured after parenteral administration. To evaluate the efficacy of calcitonin suppositories in disease states, 10 patients with moderate hypercalcemia due to malignancy were treated with salmon calcitonin, administered as suppositories containing 300 MRC units, three times a day for seven days. The mean plasma calcium level decreased significantly from 2.96 +/- 0.09 mmol/liter to 2.57 +/- 0.09 after one week (p less than 0.005) and rose again after discontinuation of treatment to 2.86 +/- 0.09 mmol/liter one week later. Urinary calcium and hydroxyproline values decreased during treatment and rose after discontinuation of treatment. The plasma calcium level decreased rapidly in six patients, becoming normal in five; three patients showed only a partial response, and one patient had no response at all. No side effects were observed, and clinical improvement was noted in nine of the 10 patients. Little or no response was observed in patients with extremely high urinary calcium or, to a lesser extent, high hydroxyproline excretion. There was a significant negative correlation between the maximal decrease in plasma calcium concentration and initial urinary calcium excretion (r -0.78, p less than 0.01). Thus, salmon calcitonin administered by the rectal route appears to be an easy, safe, and effective treatment of moderate hypercalcemia without apparent side effects.

Intravenous disodium etidronate therapy in Paget's disease of bone and hypercalcemia of malignancy. Effects on biochemical parameters and bone histomorphometry

Nineteen patients with Paget's disease and four patients with hypercalcemia of malignancy underwent hypocalcemic therapy with etidronate disodium (etidronate) administered intravenously. The dosage for patients with Paget's disease was 4.3 mg/kg/day, infused on each of seven consecutive days. Nine of the 19 patients also received oral etidronate 5 mg/kg/day for three months after administration of intravenous therapy. Etidronate administered orally sustained the decreases in urinary hydroxyproline produced by the infusions, whereas levels returned to pretreatment values in most patients receiving only the intravenously administered drug. Serum alkaline phosphatase levels were not reduced in the 10 patients receiving only intravenously administered etidronate, but they declined by approximately 50 percent in the nine patients who received the additional orally administered etidronate. Transiliac-crest bone biopsy specimens obtained three months after intravenous therapy revealed a regular lamellar structure, compared with the characteristic woven pattern of pagetic bone. In all four patients with hypercalcemia of malignancy, normocalcemia was achieved by the 10th day of treatment using a dosage of 4.3 mg/kg/day. Oral etidronate therapy was beneficial in maintaining normocalcemia.

Neoplastic hypercalcemia: physiologic response to intravenous etidronate disodium

Following a four-day control period during which an elevated serum calcium level either stabilized or continued to rise despite maximally tolerated saline diuresis, 12 patients with neoplastic hypercalcemia were treated with intravenous etidronate disodium (etidronate) 7.5 mg/kg/day for up to seven days. Serum calcium reverted to normal levels in all patients, with the mean pretreatment serum calcium level of 12.5 +/- 0.4 mg/dl dropping to 9.2 +/- 0.2 mg/dl (p less than 0.01) by Day 7. Elevated urinary calcium (1,107 +/- 134 mg/g creatinine) and hydroxyproline levels (154 +/- 16 mg/g creatinine) declined to 245 +/- 52 mg/g creatinine and 75 +/- 14 mg/g creatinine, respectively, suggesting a marked reduction in bone resorption following treatment. Serum phosphorus levels were unchanged, but urinary phosphorus levels dropped rapidly from 1,181 +/- 125 mg/g creatinine before treatment to 723 +/- 94 mg/g creatinine after two days. Serum parathyroid hormone levels (mid-molecule assay) were suppressed before treatment (64 +/- 16 pg/ml), but rose rapidly to 223 +/- 68 pg/ml by Day 7 of treatment. The value of serum 1,25-dihydroxyvitamin D was initially below normal (16 +/- 3 pg/ml), but rose rapidly with treatment to 42 +/- 12 pg/ml by Day 7. Symptoms of hypercalcemia and bone pain improved with treatment, and no serious adverse reactions to treatment were encountered. Intravenous etidronate is apparently an effective and safe treatment for neoplastic hypercalcemia.

Effect of etidronate disodium on the interactions between malignancy and bone

This study was designed to assess the capacity of etidronate disodium (etidronate) to affect neoplastic involvement of bone by murine tumors. Using sublines of the Walker 256 carcinoma, differing in the pattern of bone involvement, etidronate was found to inhibit hypercalcemia caused by systemically acting humoral factors, to inhibit bone metastasis following inoculation of tumor cells into the abdominal aorta, and to reduce the invasion of bone adjacent to tumors. Etidronate was also found to prevent bone metastasis in syngeneic rat mammary carcinoma. Etidronate was found devoid of direct antineoplastic activity, whether administered intramuscularly, subcutaneously, or intravenously, in a series of murine tumors of different histologic varieties. At the same time, it was shown that etidronate did not modify the antineoplastic activity of any of the major chemotherapeutic agents used in these studies, nor did it demonstrate any degree of immunosuppression. The experimental models used for this study should prove useful in evaluating agents that may affect the various types of bone involvement seen in neoplastic disease. The drug's apparent lack of interference with the antineoplastic activity of standard cytotoxic agents and its lack of immunosuppressive activity suggest that it may be readily adaptable to combination chemotherapy regimens.

Etidronate disodium in the management of malignancy-related hypercalcemia

To evaluate the efficacy of intravenous etidronate disodium (etidronate) in controlling hypercalcemia of malignancy, 20 patients with known malignant disease and hypercalcemia were randomly assigned on a two-to-one basis to receive etidronate, 7.5 mg/kg of body weight, or placebo for three to five days. All patients received 3,000 ml of saline and 40 mg of furosemide per day. Eighteen patients completed the study. Eleven of 12 patients (92 percent) in the etidronate group attained normocalcemia, compared with two of six (33 percent) in the placebo group (p = 0.05). The etidronate group showed a greater decrease in the serum calcium level than did the placebo group (p less than 0.02). Renal calcium excretion decreased significantly in the etidronate group but not in the placebo group. Intravenous etidronate in combination with rehydration and furosemide constitutes a safe and effective alternative in the treatment of hypercalcemia of malignancy.

Treatment with clodronate in patients with hypercalcemia secondary to malignancy

Dichloromethylene bisphosphonate (clodronate, Cl2MDP) is a synthetic analogue to pyrophosphate, which inhibits increased bone resorption. This drug was given to 12 patients with hypercalcemia secondary to advanced malignant disease. Clodronate in a daily dose of 1.6 to 3.2 g generally caused a return of the serum calcium values to normal within 5-10 days with a concomitant improvement of symptoms related to the hypercalcemia. Side effects were few. Thus, clodronate appears to be a valuable adjunct for the medical management of patients with malignancy-associated hypercalcemia.

A single-day treatment of tumor-induced hypercalcemia by intravenous amino-hydroxypropylidene bisphosphonate

Twenty patients with malignant hypercalcemia were treated with amino-hydroxypropylidene bisphosphonate (AHPrBP, previously APD), a potent inhibitor of osteoclast-mediated bone resorption. To assess the efficacy of a single-day treatment and determine the optimal dose of this compound, all patients received AHPrBP intravenously over 24 h, but they were divided into two subsequent groups of 10 patients: Group A received a single dose of 60 mg AHPrBP and group B received a single dose of 30 mg. In both groups all patients responded to AHPrBP with a decrease in plasma calcium concentration after a mean time lag of 1 day. Within 6 days, plasma calcium (corrected for serum proteins) fell from 3.24 +/- 0.14 to 2.24 +/- 0.06 mmol/liter in group A (p less than .001), but only from 3.22 +/- 0.15 to 2.49 +/- 0.10 mmol/liter in group B (p less than .005). Whereas in all patients from group A plasma calcium was within the normal range at days 9 and 14, in 4 patients of group B it was still above the normal range at day 9, and in 5 patients at day 14. There was a significant difference in plasma calcium between group A and group B from days 5 to 14 (p less than .005). In both groups, urinary calcium excretion fell dramatically and similarly, and plasma phosphate concentration decreased significantly (p less than .01) to values slightly below the normal range from days 4 to 6.(ABSTRACT TRUNCATED AT 250 WORDS)

Etidronate disodium for treating hypercalcaemia of malignancy: a double blind, placebo-controlled study

The efficacy of intravenous etidronate disodium in controlling hypercalcaemia of malignancy was evaluated in a double blind, placebo-controlled study. Twenty patients with known malignant disease and hypercalcaemia were randomly assigned on a 2:1 basis to etidronate 7.5 mg kg-1 body weight or placebo for 3-5 days. All patients received 3000 ml saline and 40 mg furosemide per day. Eighteen patients completed the study. Eleven of twelve in the etidronate group reached normocalcaemia compared to two of six in the placebo group (P = 0.05). The etidronate group showed a greater decrease in serum calcium than the placebo group (P less than 0.02). The renal calcium excretion decreased significantly in the etidronate group, but not in the placebo group. A slight increase in serum creatinine was observed in the etidronate group compared to placebo on the first day of treatment. The difference however disappeared the following days. Intravenous etidronate treatment in combination with rehydration and furosemide constitutes a safe and efficient alternative in the treatment of hypercalcaemia of malignancy, although a first approach always should be rehydration.

Quantitative morphometric evaluation of the inhibitory activity of new aminobisphosphonates on bone resorption in the rat

Three new bisphosphonates of various chain length, namely, 4-amino-1-hydroxybutylidene-1,1-bisphosphonate (AHBuBP), 5-amino-1-hydroxypentylidene-1,1-bisphosphonate (AHPeBP), and 6-amino-1-hydroxyhexylidene-1,1-bisphosphonate (AHHexBP) were compared with 3-amino-1-hydroxypropylidene-1,1-bisphosphonate (AHPrBP), and dichloromethylene bisphosphonate as to their effect on metaphyseal bone remodeling in the rat. The parameters assessed were growth in length, mineralization, metaphyseal density, mean trabecular diameter, and number of trabeculae. Both metaphyseal density, an index of metaphyseal Ca balance, and number of trabeculae, an index of bone resorption, showed the following sequence of potency: AHBuBP greater than AHPrBP = AHPeBP = AHHexBP greater than Cl2MBP. All compounds decreased trabecular diameter somewhat, an index of bone formation, with AHBuBP decreasing the least. AHBuBP and possibly AHHexBP appear to be interesting new bisphosphonates for future clinical use.

Osteolytic bone metastases in breast carcinoma pathogenesis, morbidity and bisphosphonate treatment

In this review different aspects of osteolytic bone metastasis of breast carcinoma including morbidity, pathogenesis, accompanying hypercalcaemia and treatment, are discussed. Bone metastases occur in many patients with breast cancer (percentages of up to 85% have been reported); although patients seldom die of bone metastases morbidity is pronounced. Literature data point out that humoral factors, such as prostaglandins and the recently described growth factors are of importance beside cell interactions between monocytes, lymphocytes, osteoclasts and tumour cells. Nowadays, no significance is attributed to parathyroid hormone (PTH) overproduction in this respect. The differential diagnosis between primary hyperparathyroidism and tumour-induced hypercalcaemia is not always easy biochemically; combinations of both do occur less frequently than has been assumed in the past. A new and promising line of investigations involves the growth factors, which can increase osteolytic bone resorption and may bind to epidermal growth factor (EGF) or PTH receptors, thus inducing some of the biological effects of PTH (including hypercalcaemia). Until recently it was exceedingly difficult to treat tumour-induced hypercalcaemia (TIH) (the acute condition). Since the availability of the bisphosphonates dichloromethylidene bisphosphonate (Cl2MDP) and 3-amino-1-hydroxypropylidene-1, l-bisphosphonate (APD) this treatment has become very simple. Preliminary results, derived from the literature, point out that bisphosphonate treatment might also be effective in providing long-term control.

Renal handling of calcium and sodium in metastatic and non-metastatic malignancy

Investigation of the renal handling of calcium and sodium in rehydrated patients with hypercalcaemia associated with malignancy showed enhanced reabsorption of calcium in most cases. This was a feature of both metastatic and non-metastatic malignancy, and in this respect the patients were indistinguishable from patients with primary hyperparathyroidism. As the increased calcium reabsorption was inversely correlated with the rate of excretion of sodium modest salt loading can be used to inhibit this process. This is an important practical aspect of the treatment of patients with this type of hypercalcaemia.