A dose-finding study of zoledronate in hypercalcemic cancer patients

Effect of Primary Stabilisation on Osseointegration of Implants With Local and Systemic Zoledronic Acid Application

ABSTRACT

Primary stabilization (PS) is defined as initial tight fit during the surgical placement of an implant. Tight implant placement is quite difficult in cases where bone quality and quantity are insufficient. Zoledronic acid (ZA) is a powerful bisphosphonate that prevents bone resorption. The aim of this study is to investigate the effect of local and systemic ZA application on osseointegration in titanium implants with and without PS. Male Sprague Dawley rats were divided into 2 main groups, with PS, PS + (n = 24), and without primary stabilisation, PS - (n = 24). These main groups were divided into control (n = 8), 2 mg/1 mL local ZA (n = 8) and 0.1 mg/kg systemic ZA (n = 8) groups. All of the subjects were sacrificed after a 4-week recovery period. Bone implant connection (BIC) and thread filling (TF) (%) of the samples was analyzed according to the non-decalcified histological analysis method. In terms of BIC percentages and TF, statistically significant differences were found between the groups with and without PS and between the ZA treatment groups (P < 0.05). The common effect of PS and ZA use on the percentage of BIC was found to be statistically significant (P < 0.05). The common effect of PS and acid type on TF was not statistically significant (P < 0.05). Within the limitations of this study, it may be concluded that systemic and local administration of ZA may increase implant osseointegration.

Disorders of Divalent Ions (Magnesium, Calcium, and Phosphorous) in Patients With Cancer

Disorders of the divalent ions (magnesium, calcium, and phosphorous) are frequently encountered in patients with cancer. Of these, hypomagnesemia, hypocalcemia, hypercalcemia, and hypophosphatemia are seen most commonly. These electrolyte disturbances may be related to the underlying malignancy or due to side effects of anticancer therapy. When caused by a paraneoplastic process, these abnormalities may portend a poor prognosis. Importantly, the development of severe electrolyte derangements may be associated with symptoms that negatively impact quality of life, preclude the administration of critical chemotherapeutic agents, or lead to life-threatening complications that require hospitalization and emergent treatment. In accordance, prompt recognition and treatment of these disorders is key to improving outcomes in patients living with cancer. This review will discuss selected derangements of the divalent ions seen in this population, with a focus on paraneoplastic and therapy-associated etiologies.

The Causes of Hypo- and Hyperphosphatemia in Humans

Phosphate homeostasis involves several major organs that are the skeleton, the intestine, the kidney, and parathyroid glands. Major regulators of phosphate homeostasis are parathormone, fibroblast growth factor 23, 1,25-dihydroxyvitamin D, which respond to variations of serum phosphate levels and act to increase or decrease intestinal absorption and renal tubular reabsorption, through the modulation of expression of transcellular transporters at the intestinal and/or renal tubular level. Any acquired or genetic dysfunction in these major organs or regulators may induce hypo- or hyperphosphatemia. The causes of hypo- and hyperphosphatemia are numerous. This review develops the main causes of acquired and genetic hypo- and hyperphosphatemia.

Bisphosphonates and breast cancer - From cautious palliation to saving lives

Bone metastases are common in breast cancer and may cause considerable morbidity including fractures, severe pain, nerve compression and hypercalcaemia. Alongside developments in the multidisciplinary management for patients with metastatic breast cancer, the use of bisphosphonates, and more recently denosumab, has transformed the course of advanced breast cancer for many patients resulting in a major reduction in skeletal complications, reduced bone pain and improved quality of life. Additionally, because the bone marrow microenvironment is so intimately involved in the metastatic processes required for cancer dissemination, the use of adjuvant bisphosphonates has been studied extensively over the past 25 years in many randomised trials. We now have clear evidence that bisphosphonates significantly reduce both metastasis to bone and mortality in postmenopausal women with early breast cancer. Efficacy seems similar across different biological subgroups of postmenopausal breast cancer with the use of either a nitrogen-containing bisphosphonate such as intravenous zoledronate or daily oral ibandronate as well as the non-nitrogen containing agent, daily oral clodronate. In this overview of evolving role of bisphosphonates in breast cancer, focussing particularly on pamidronate and zoledronate, the long winding development road from the 1970s through to the present day is described and some of the serendipitous findings, "lucky breaks" and regulatory decisions along the way outlined.

Symptomatic hypocalcemia following a single dose of zoledronic acid in a patient with bone metastases secondary to breast cancer

INTRODUCTION

The use of bisphosphonates is increasing, for treatment of hypercalcemia and pain in cancer, and post-menopausal osteoporosis and also to decrease the risk of skeletal morbidity in multiple myeloma and metastatic breast cancer.

CASE REPORT

A single dose of zoledronic acid was administered for hypercalcemia in a 54-year-old woman breast cancer patient with extensive bone metastasis. After the first dose, the patient developed symptomatic hypocalcemia.Management and outcome: Simultaneous hypocalcemia, hypophosphatemia, and vitamin D deficiency were detected in the patient. In the symptomatic process, intravenous, then oral replacement was performed.

DISCUSSION

There is a need for taking precautionary measures such as vitamin D, serum phosphorus and, calcium monitoring and supplementation to prevent life-threatening complications, such as symptomatic hypocalcemia, especially in populations with vitamin D deficiency like ours.

Persistent Increase in Serum 25-Hydroxyvitamin D Concentration in a Dog Following Cholecalciferol Intoxication

Cholecalciferol is becoming an increasingly utilized rodenticide in the United States due to changes implemented by the Environmental Protection Agency (EPA) to reduce unintended exposure of wildlife to second-generation anticoagulant rodenticides. The lipophilic properties of cholecalciferol and prolonged tissue elimination are well-documented; however, long-term clinical ramifications are unknown. This report describes unique clinicopathologic and treatment features during the acute phase of cholecalciferol rodenticide toxicosis in a 4-year-old neutered Shih-Tzu mix that presented for intermittent vomiting, anorexia, polyuria, and polydipsia. In addition, this report also highlights the potential benefit of serial measurements of serum 25-hydroxyvitamin D concentrations and long-term treatment in the chronic phase of cholecalciferol rodenticide toxicosis in dogs.

Management of bone health in solid tumours: From bisphosphonates to a monoclonal antibody

Patients with solid tumours are at risk of impaired bone health from metastases and cancer therapy-induced bone loss (CTIBL). We review medical management of bone health in patients with solid tumours over the past 30 years, from first-generation bisphosphonates to the receptor activator of nuclear factor κB ligand (RANKL)-targeted monoclonal antibody, denosumab. In the 1980s, first-generation bisphosphonates were shown to reduce the incidence of skeletal-related events (SREs) in patients with breast cancer. Subsequently, more potent second- and third-generation bisphosphonates were developed, particularly zoledronic acid (ZA). Head-to-head studies showed that ZA was significantly more effective than pamidronate for reducing SREs in patients with breast and castrate-resistant prostate cancer (CRPC), becoming the standard of care for more than a decade. The RANKL inhibitor denosumab was licensed in 2010, and head-to-head studies and integrated analyses confirmed its superiority to ZA for preventing SREs, particularly in breast cancer and CRPC. Bisphosphonates and denosumab have also been investigated for prevention of CTIBL in patients receiving hormonal therapy for breast and prostate cancer, and denosumab is licensed in this indication. Despite advances in management of bone health, several issues remain, notably the optimal time to initiate therapy, duration of therapy, and dosing frequency, and how to avoid toxicity, particularly with long-term treatment. In summary, introduction of ZA and denosumab has protected patients with bone metastasis from serious bone complications and improved their quality of life. Ongoing research will hopefully guide the optimal use of these agents to help maintain bone health in patients with solid tumours.

Pharmacology of bisphosphonates

The biological effects of the bisphosphonates (BPs) as inhibitors of calcification and bone resorption were first described in the late 1960s. In the 50 years that have elapsed since then, the BPs have become the leading drugs for the treatment of skeletal disorders characterized by increased bone resorption, including Paget's disease of bone, bone metastases, multiple myeloma, osteoporosis and several childhood inherited disorders. The discovery and development of the BPs as a major class of drugs for the treatment of bone diseases is a paradigm for the successful journey from "bench to bedside and back again". Several of the leading BPs achieved "blockbuster" status as branded drugs. However, these BPs have now come to the end of their patent life, making them highly affordable. The opportunity for new clinical applications for BPs also exists in other areas of medicine such as ageing, cardiovascular disease and radiation protection. Their use as inexpensive generic medicines is therefore likely to continue for many years to come. Fifty years of research into the pharmacology of bisphosphonates have led to a fairly good understanding about how these drugs work and how they can be used safely in patients with metabolic bone diseases. However, while we seemingly know much about these drugs, a number of key aspects related to BP distribution and action remain incompletely understood. This review summarizes the existing knowledge of the (pre)clinical and translational pharmacology of BPs, and highlights areas in which understanding is lacking.

Indirect Evaluation of Bone Saturation with Zoledronic Acid After Long-Term Dosing

BACKGROUND

Zoledronic acid (ZA), a potent bisphosphonate used for treatment of bone metastasis, has high bone affinity. This post hoc analysis evaluated the effects of long-term treatment and reduction in dosing frequency of ZA on bone saturation.

MATERIALS AND METHODS

Pharmacokinetic data from three independent studies, OPTIMIZE-2 (patients receiving ≥9 doses of bisphosphonates) and two phase I studies, CZOL4460503 and CZOL4460506 (patients who were bisphosphonate naïve/bisphosphonate free for ≥1 year after previous dosing), were pooled. Serial urine and plasma samples were used as surrogate markers to determine ZA plasma area under the curve (AUC) over 6 hours (AUC_0-6h) and dose excreted in urine over 6 hours (urine_0-6h). Potential relationships between the number of years for which patients had been treated previously at time of study entry and AUC_0-6h or urine_0-6h were analyzed graphically.

RESULTS

Creatinine clearances for patients were similar across the three studies and at all time points analyzed. The levels of AUC_0-6h ZA in plasma at week 0 in every (q) 4 and q12 weekly arms of OPTIMIZE-2 were 0.366 h × mg/L and 0.397 h × mg/L compared with 0.345 h × mg/L and 0.356 h × mg/L in CZOL4460503 and CZOL4460506, respectively. In OPTIMIZE-2, the AUC_0-6h ZA plasma levels were the same (0.428 h × mg/L) at week 36 in both q4 and q12 arms. The levels of ZA urine_0-6h at week 36 in OPTIMIZE-2 (q4 and q12 week arms), CZOL4460503, and CZOL4460506 were 36.6%, 30.8%, 26.5%, and 27.3%, respectively.

CONCLUSION

Long-term ZA treatment may not impact bone saturation, and ZA dosing frequency does not seem to influence drug retention rates.

IMPLICATIONS FOR PRACTICE

Zoledronic acid (ZA), used along with standard antineoplastic therapy to treat bone metastases associated with solid tumors and multiple myeloma, requires frequent (every 3-4 or every 12 weeks) long-term administration. This may result in bone saturation and subsequently lead to a higher risk of adverse events such as osteonecrosis of the jaw and atypical fractures. This post hoc analysis used surrogate markers to demonstrate that prolonged ZA administration does not cause bone saturation. Furthermore, reduction in ZA dosing frequency does not affect its retention level in bones over time. These findings will help in addressing clinicians' concerns regarding prolonged ZA administration.

Twist on a classic: vitamin D and hypercalcaemia of malignancy

Malignancy is the most common cause of hypercalcaemia in the inpatient setting. Most cases are caused by tumour production of parathyroid hormone-related protein and osseous metastases. In less than 1% of cases, hypercalcaemia is driven by increased production of 1,25-dihydroxyvitamin D (1,25(OH)₂D), a mechanism most commonly seen in haematological malignancies. Here, we describe a woman with metastatic small cell cervical carcinoma who developed hypercalcaemia secondary to paraneoplastic overproduction of 1,25(OH)₂D, a finding that, to our knowledge, has not been previously associated with this cancer. We also review the current cases of solid tumours reported to have this mechanism of hypercalcaemia and the evidence behind multiple therapeutic approaches.

Safety, pharmacokinetics, and changes in bone metabolism associated with zoledronic acid treatment in Japanese patients with primary osteoporosis

Although once-yearly intravenous administration of zoledronic acid has been reported to inhibit bone resorption and increase bone mineral density, no studies have evaluated its effectiveness in treating osteoporosis in Japanese patients. Therefore, the purpose of this study was to investigate the pharmacokinetics and assess the safety of and changes in bone metabolism associated with zoledronic acid treatment in Japanese patients with primary osteoporosis. This was a single-administration study with a single-blind parallel-group design. The study participants were 24 Japanese patients with primary osteoporosis. The patients were divided into two groups, with each group receiving a single injection of zoledronic acid (4 or 5 mg). Pharmacokinetics and urinary excretion were then compared, and drug-related adverse events and changes in the levels of bone turnover markers were assessed at 12 months. Mean plasma concentrations of zoledronic acid peaked in both groups immediately after administration, and decreased to 1% or less of peak levels after 24 h. Noncompartmental analysis revealed that C _max and the area under the curve from time zero to infinity increased in proportion to the dose. The levels of bone resorption and formation markers decreased from day 15 and from 3 months after administration respectively, and suppression of these markers remained constant for the entire study period. No serious adverse events were reported. There was no large difference between the 4- and 5-mg groups in terms of pharmacokinetics, changes in the levels of bone turnover markers, and safety profiles. This study demonstrated acceptable pharmacokinetics and changes in bone metabolism associated with zoledronic acid treatment in female Japanese osteoporosis patients. Both the 4-mg dose and the 5-mg dose demonstrated acceptable safety and sustained antiresorptive effects for the duration of the study.

Zoledronic Acid Inhibits Osteoclastogenesis in Vitro and in a Mouse Model of Inflammatory Osteolysis

This study assessed effects of the bisphosphonate zoledronic acid (ZLNA) on osteoclastogenesis. To assess the effect of ZLNA on osteoclast formation in vitro, we cultured mouse bone marrow cells under conditions that promote osteoclastogenesis. Administered at concentrations from 10−6 to 10−9 mol/L, ZLNA led to a dose-dependent inhibition of osteoclastogenesis. Combined TUNEL staining and histochemical staining for tartrate-resistant acid phosphatase showed that ZLNA induced apoptosis in osteoclasts and monocytic precursor cells. To study the effects of ZLNA in vivo, we placed keratin particles onto the surface of the parietal bone of mice to induce localized inflammatory bone resorption. Three experimental groups received daily subcutaneous injections of ZLNA (1, 3, or 10 μg/kg body weight) from 4 days before surgery until 5 days after keratin implantation. The ZLNA significantly reduced osteoclast recruitment in a dose-dependent manner, but did not affect the degree of inflammation or the mineral apposition rate.

Zoledronic Acid Effect on Chondrocyte Apoptosis in Degenerative Osteoarthritis Model

Apoptosis refers to cell death without inflammatory process, and is related to degenerative changes in joints. We hypothesized that zoledronic acid (ZA) would have a positive effect on chondrocyte viability and decreases in chondrocyte loss, which are important for the progression of degeneration. This study aimed to reveal the difference in time-dependent apoptotic changes in cartilage tissue in the anterior cruciate ligament (ACL) transection model of osteoarthritis (OA) in rat knees after treatment with zoledronic acid. We randomly divided 48 male Wistar albino rats into 6 groups. The knees of all rats except those in the control group underwent the operation for ACL transection. ZA for half of the rats and saline solution for the others was injected weekly into knees. Animals were killed at 0, 3, and 6 weeks after surgery. Apoptosis of chondrocytes were analyzed using the terminal deoxynucleotidyl transferase dUTP nick end labeling method. Comparison of groups was performed using Kruskal Wallis analysis and the Mann Whitney U test. Significant differences were observed between the groups treated with ZA and saline. ZA treatment significantly decreased the number of apoptotic cells in chondral tissue. ZA prevents time-dependent degenerative changes in chondral tissue by decreasing chondrocyte death. Intra-articular ZA may have the potential to treat and conserve chondral viability. ZA prevents chondrocyte loss and may play a therapeutic role in OA and conserving joint health. Further studies are needed to evaluate the potential of intra-articular ZA for the prevention or treatment of age-related degenerative changes.

A Case of Severe, Prolonged, Refractory Hypophosphatemia After Zoledronic Acid Administration

Zoledronic acid (ZA) administration has been associated with electrolyte abnormalities, including hypocalcemia, hypomagnesemia, hypokalemia, and hypophosphatemia. We describe a case of severe, refractory hypophosphatemia in a patient who received ZA for hypercalcemia of malignancy (HCM). Little data are available that describe the incidence or degree of severity of hypophosphatemia that can occur following ZA administration. In addition, no formal recommendations exist to guide monitoring for or management of electrolyte derangements in the setting of bisphosphonate use. Our patient required daily, high-dose phosphorus replacement beginning day 4 following ZA administration. The average daily dose of phosphorus, including both intravenous and enteral administration, was highest in the first 2 weeks after ZA, averaging 77 mmol/d days 4 through 15, and does not include sources of phosphorus from the patient’s nutrition support. Despite this high amount of supplementation, which was well beyond what meets normal daily requirements and the amount expected to treat “usual” hypophosphatemia, the patient did not achieve sustained normal serum phosphorus levels for over 30 days after ZA. ZA is a favorable option for treating HCM because of its longer duration of action, potent serum calcium-lowering effects, and favorable safety profile. The risk of hypophosphatemia with ZA use is reviewed.

Targeting bone metastases in prostate cancer: improving clinical outcome

Bone metastases develop in most patients with metastatic castration-resistant prostate cancer (mCRPC). They affect the structural integrity of bone, manifesting as pain and skeletal-related events (SREs), and are the primary cause of patient disability, reduced quality of life (QOL) and death. Understanding the pathophysiology of bone metastases resulted in the development of agents that improve clinical outcome, suggesting that managing both the systemic disease and associated bone events is important. Historically, the treatment of CRPC bone metastases with early radiopharmaceuticals and external beam radiation therapy was largely supportive; however, now, zoledronic acid and denosumab are integral to the therapeutic strategy for mCRPC. These agents substantially reduce skeletal morbidity and improve patient QOL. Radium-223 dichloride is the first bone-targeting agent to show improved survival and reduced pain and symptomatic skeletal events in patients with mCRPC without visceral disease. Five other systemic agents are currently approved for use in mCRPC based on their ability to improve survival. These include the cytotoxic drugs docetaxel and cabazitaxel, the hormone-based therapies, abiraterone and enzalutamide, and the immunotherapeutic vaccine sipuleucel-T. Abiraterone and enzalutamide are able to reduce SREs and improve survival in this setting. Novel agents targeting tumour and bone cells are under clinical development.

Zoledronate induces osteonecrosis of the jaw in sheep

INTRODUCTION

The treatment of bisphosphonate-related osteonecrosis of the jaw has become routine in maxillofacial hospitals. However, the etiopathology has not yet been fully understood. The aim of this study was to develop a large animal model for medication-related osteonecrosis of the jaw (MRONJ).

MATERIAL AND METHODS

Eight Swiss mountain sheep were randomly assigned into two groups. Group I received 0.075 mg/kg zoledronate (ZOL) intravenously every third week for 16 weeks. After 16 weeks, extraction of the first and second lower left premolar was performed. Group II underwent surgery and no ZOL was administered. After surgery, Group I continued to receive ZOL infusions; after 16 weeks, all animals were euthanized. The jaw bones were investigated macroscopically, radiographically (computed tomography) and histologically.

RESULTS

Osteonecrosis of the jaw was observed at all extraction sites in all the animals receiving ZOL, and at none of the sites in animals without ZOL. All ZOL-treated animals spontaneously developed exposed bone lesions in the oral cavity at sites where no surgical intervention was performed. CT imaging shows persistent alveolar extraction sockets 16 weeks after surgery in all animals of the ZOL-group, and healed alveolar extraction sockets in non-ZOL-treated animals.

CONCLUSION

Sheep treated with ZOL reproducibly demonstrated osteonecrosis of the jaw after tooth extraction, and spontaneous development of exposed bone in the oral cavity at sites where no manipulation was performed. This animal model can be used for further research in the fields of BP-ONJ etiopathology, oral implantology, bone and fracture healing and periodontology.

Zoledronate induces bisphosphonate-related osteonecrosis of the jaw in osteopenic sheep

OBJECTIVES

Bisphosphonate-related osteonecrosis of the jaw (BP-ONJ) occurs in 1 % of patients with medication-induced osteoporosis treated with bisphosphonates. Sheep are an established large animal model for investigating osteoporotic skeletal changes. Zoledronate significantly reduces tissue mineral variability in ovariectomized sheep. The aim of this study was to analyze bone healing after tooth extraction in sheep with induced osteopenia and zoledronate administration.

MATERIALS AND METHODS

Eight adult ewes were randomly divided into two groups of four animals. All sheep underwent ovariectomy and a low-calcium diet. Dexamethasone was administered weekly for 16 weeks. Zoledronate was then given every third week for a further 16 weeks in four sheep; these infusions were repeated after extraction of two lower premolars. Four sheep without zoledronate administrations served as controls.

RESULTS

Due to general health conditions, two sheep of the zoledronate group had to be excluded before surgery. The remaining two sheep of this group developed BP-ONJ lesions at the extraction site and various other sites in both jaws. Control group animals showed uneventful wound healing. Histology of the alveolar processes as well as lumbar spine revealed larger portions of old bone and smaller portions of new bone in the zoledronate group.

CONCLUSIONS

This animal study showed uneventful wound healing after tooth extraction in osteopenic sheep whereas zoledronate treatment leads to development of BP-ONJ-like lesions.

CLINICAL RELEVANCE

As bisphosphonate administration is a standard treatment for glucocorticoid-induced osteoporosis, this model can be used for further research in pathogenesis and management of bisphosphonate-related adverse events.

Phosphate homeostasis and disorders

Recent studies of inherited disorders of phosphate metabolism have shed new light on the understanding of phosphate metabolism. Phosphate has important functions in the body and several mechanisms have evolved to regulate phosphate balance including vitamin D, parathyroid hormone and phosphatonins such as fibroblast growth factor-23 (FGF23). Disorders of phosphate homeostasis leading to hypo- and hyperphosphataemia are common and have clinical and biochemical consequences. Notably, recent studies have linked hyperphosphataemia with an increased risk of cardiovascular disease. This review outlines the recent advances in the understanding of phosphate homeostasis and describes the causes, investigation and management of hypo- and hyperphosphataemia.

FGF23: mediator of poor prognosis in a sizeable subgroup of patients with castration-resistant prostate cancer presenting with severe hypophosphatemia?

Castration-resistant prostate cancer (CRPC) is an advanced and incurable stage of the second most frequently diagnosed malignancy in men globally. Current treatment options improve survival modestly but eventually fail due to intrinsic or acquired therapeutic resistance. A hypothesis is presented wherein circulating levels of fibroblast growth factor 23 (FGF23), an endocrine member of the fibroblast growth factor family with phosphaturic properties, are proposed as a prognostic and predictive marker to identify CRPC patients with poor prognosis that are amenable to FGF23 antibody therapy (FGF23i) or treatment with fibroblast growth factor receptor inhibitors (FGFRi). With respect to the latter, FGF23 may also serve as a pharmacodynamic marker enabling individualized FGFRi dosing. We recently discovered that the development of severe and sustained hypophosphatemia in CRPC patients undergoing zoledronic acid therapy for bone metastases was associated with markedly worse prognosis compared to patients without or with only mild and transient hypophosphatemia. Severe hypophosphatemia is a typical manifestation of tumor-induced hypophosphatemic osteomalacia (TIO), a paraneoplastic condition mediated by FGF23 overexpression in most instances. While the postulated tumor-promoting role of FGF23 in CRPC or other malignancies has not yet been studied, several lines of evidence suggest that FGF23 may mediate both severe hypophosphatemia (via its endocrine properties) and aggressive CRPC behavior (via autocrine and paracrine activities): (i) FGF23 and the necessary signalling machinery (i.e. members of the fibroblast growth factor receptor [FGFR] family and the essential co-receptor α-KLOTHO [KL]) are highly expressed in a sizeable subgroup of CRPC patients; (ii) FGF/FGFR signalling plays important roles in prostate cancer; (iii) FGF23 can induce its own expression via a positive autocrine feedback loop involving FGFR1; and (iv) this positive feedback loop may be triggered by bone-targeted therapies frequently used for the treatment of CRPC-associated bone metastases. While there is a lack of personalized treatment strategies in the management of CRPC to date, FGF23 targeted therapy has the potential to fill this unmet clinical need in the not-so-distant future. In fact, FGFRi are currently in advanced clinical testing for a number of malignancies such as kidney and lung cancer, but there is a lack of conclusive data on FGFRi therapy in patients selected for FGF/FGFR pathway activation.

Onco-nephrology: the pathophysiology and treatment of malignancy-associated hypercalcemia

Hypercalcemia complicates the course of 10%-30% of all patients with malignancies and can be a sign of very poor prognosis and advanced malignancy. Prompt recognition of the nonspecific signs and symptoms of hypercalcemia and institution of therapy can be lifesaving, affording the opportunity to address the underlying etiology. The mechanisms of malignancy-associated hypercalcemia generally fall into three categories: humoral hypercalcemia due to secreted factors (such as parathyroid-related hormone), local osteolysis due to tumor invasion of bone, and absorptive hypercalcemia due to excess vitamin D produced by malignancies. The mainstays of therapy for hypercalcemia are aggressive intravenous volume expansion with saline, bisphosphonate therapy, and perhaps loop diuretics. Adjunctive therapy may include calcitonin and corticosteroids. In refractory cases, gallium nitrate and perhaps denosumab are alternatives. In patients presenting with severe AKI, hemodialysis with a low-calcium bath can be effective. In most cases, therapy normalizes calcium levels and allows for palliation or curative therapy of the malignancy.

The effect of systemically administrated zoledronic acid on the osseointegration of dental implants

OBJECTIVE

The aim of conducting this study was to evaluate the effect of zoledronic acid (ZA) on the new bone formation (NBF) after the insertion of a titanium dental implant, which is very popular treatment in dentistry.

STUDY DESIGN

Twelve New Zealand white rabbits were used in this study. The rabbits were divided in two groups. ZA was systemically administered to the study group. Titanium implants were placed to the left and right tibias of the rabbits.

RESULTS

The data from the ZA group revealed a statistically significant increase in the bone mineral content and the bone mineral density. A non-decalcified histomorphometric examination conducted on the study group revealed a significant increase of NBF and bone-implant contact (BIC) at 2 and 4 weeks.

CONCLUSION

A single dose of systemic ZA administration increases the rate of NBF and augments the quality of the bone.

Zoledronic acid for adjuvant use in patients with breast cancer

Zoledronic acid, a nitrogen-containing bisphosphonate, is firmly established in the management of metastatic bone disease. It inhibits farnesyl diphosphonate synthase within the mevalonate pathway and, through this mechanism, is a potent inhibitor of osteoclast-mediated bone resorption. In addition, there are preclinical data suggesting that farnesyl diphosphonate synthase inhibition by zoledronic acid has anti-tumor effects in breast cancer. Adjuvant therapies for early breast cancer are associated with substantial decreases in bone mineral density. Results from three clinical trials, ABCSG-12, Z-FAST and ZO-FAST, indicate that the addition of twice-yearly zoledronic acid to standard adjuvant endocrine therapy in premenopausal and postmenopausal patients with hormone receptor-positive breast cancer prevents cancer treatment-induced bone loss. Moreover, it is becoming evident that it may also exert anticancer effects in an estrogen-deprived state in the adjuvant and neoadjuvant setting. However, long-term side effects need to be taken into consideration for treatment decisions.

Serologic bone markers for predicting development of osteonecrosis of the jaw in patients receiving bisphosphonates

PURPOSE

Osteonecrosis of the jaw is a well-documented side effect of bisphosphonate (BP) use. Attempts have recently been made to predict the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ). We prospectively investigated the predictive value of serum levels of C-terminal telopeptide of collagen I (CTX), bone-specific alkaline phosphatase, and parathyroid hormone for the development of BRONJ.

PATIENTS AND METHODS

Data on the demographics, comorbidities, and BP treatment were collected from 78 patients scheduled for dentoalveolar surgery. Of the 78 patients, 51 had been treated with oral BPs and 27 had been treated with frequent intravenous infusions of BPs. Blood samples for CTX, bone-specific alkaline phosphatase, and parathyroid hormone measurements were taken preoperatively. Surgery was performed conservatively, and antibiotic medications were prescribed for 7 days.

RESULTS

Of the 78 patients, 4 patients taking oral BPs (7.8%) and 14 receiving intravenous BPs (51.8%) developed BRONJ. A CTX level less than 150 pg/mL was significantly associated with BRONJ development, with an increased odds ratio of 5.268 (P = .004). The bone-specific alkaline phosphatase levels were significantly lower in patients taking oral BPs who developed BRONJ. The parathyroid hormone levels were similar in patients who did and did not develop BRONJ.

CONCLUSION

The incidence of BRONJ after oral surgery involving bone is greater among patients receiving frequent, intravenous infusions of BPs than among patients taking oral BPs. Although the measurement of serum levels of CTX is not a definitive predictor of the development of BRONJ, it might have an important role in the risk assessment before oral surgery.

Medication-induced hypophosphatemia: a review

Hypophosphatemia (serum phosphorus concentration <2.5 mg/dl, 0.8 mmol/l), although rare in the general population, is commonly observed in hospitalized patients and may be associated with drug therapy. In fact, hypophosphatemia frequently develops in the course of treatment with drugs used in every-day clinical practice including diuretics and bisphosphonates. Proper diagnostic approach of patients with low serum phosphorus concentrations should involve a detailed medical history with special attention to the recent use of medications. The clinical manifestations of drug-induced hypophosphatemia are usually mild but might also be severe and potentially life-threatening. This review aims at a thorough understanding of the underlying pathophysiological mechanisms and risk factors of drug therapy-related hypophosphatemia thus allowing prevention and effective intervention strategies.

Cancer treatment dosing regimens of zoledronic acid result in near-complete suppression of mandible intracortical bone remodeling in beagle dogs

Bisphosphonate doses used in cancer treatment are substantially higher than those used for osteoporosis. Little is known about the effects of these high doses on tissue-level remodeling suppression. The aim of this study was to assess the effects of cancer dosing regimens of zoledronic acid on tissue-level bone remodeling at different skeletal sites. Skeletally mature female beagle dogs were treated with monthly intravenous infusions of vehicle (VEH, saline) or zoledronic acid (ZOL, 0.067 mg/kg); an additional group of animals was treated daily with oral alendronate (ALN, 0.2 mg/kg/day). Doses of ZOL and ALN were, on a milligram per kilogram basis, consistent with those used for cancer and osteoporosis, respectively. Following either 3 or 6 months of treatment, animals were euthanized, and mandible, rib, and tibia were processed for dynamic bone histology. There was no evidence of oral lesions or bone matrix necrosis in the mandibles of any animals. After 3 months, the rate of intracortical bone remodeling in the mandible was significantly suppressed with ZOL (-95%) compared with VEH; by 6 months, ZOL had produced nearly complete suppression (-99%) compared with VEH. ZOL also significantly suppressed remodeling in the rib cortex at both 3 (-83%) and 6 (-85%) months compared with VEH; tibia cortex bone formation rate was nonsignificantly lower with ZOL treatment (-68% to -75%). Remodeling suppression in ZOL-treated animals was significantly greater than in ALN-treated animals at both the mandible and the rib; ALN and VEH were not different for any of the assessed parameters at any of the sites. Compared across skeletal sites, the absolute level of remodeling suppression with ZOL treatment was significantly greater at sites with higher remodeling, whereas the percent reduction was similar among the sites. These results document nearly complete intracortical remodeling suppression resulting from monthly intravenous zoledronic acid dosing, with changes being most dramatic at the mandible.

Bisphosphonate-related osteonecrosis of the jaws: a single-center study of 101 patients

PURPOSE

Osteonecrosis of the jaw (ONJ) is a devastating side effect of long-term bisphosphonate (BP) use. We present the largest case series from a single department.

MATERIALS AND METHODS

This case series included 101 ONJ patients. Data on demographics, medical background, type and duration of BP use, possible triggering events, mode of therapy, and outcome were recorded.

RESULTS

ONJ was associated with intravenous BPs in 85 patients and with oral BPs in 16 patients. It was diagnosed after 48, 27, and 67 months of pamidronate, zoledronic acid, and alendronate use, respectively. Long-term antibiotics and minimal surgical procedures resulted in complete or partial healing in 18% and 52% of the patients, respectively; 30% had no response. There was no association between ONJ and diabetes, steroid and antiangiogenic treatment, or underlying periodontal disease. Diagnostic biopsies aggravated lesions without being informative about pathogenesis. A conservative regimen is our treatment of choice.

CONCLUSION

Solutions for decreasing morbidity and poor outcome of ONJ remain elusive.

Poor Survival Outcome With Moderate and Severe Hypercalcemia in Gynecologic Malignancy Patients

Objective:

Determine the incidence of hypercalcemia in gynecologic malignancy patients and their survival outcome.

Design:

Single-institution retrospective clinical study.

Patients and Methods:

We used Fisher exact test, Kaplan-Meier survival curves, and Cox proportional hazards model to analyze demographic and clinical data from gynecologic malignancy patients with hypercalcemia who had been treated at The University of Texas M. D. Anderson Cancer Center from September 1997 to August 2006.

Results:

Of the 5260 gynecologic malignancy patients, 268 had hypercalcemia (5%). Of the 268, 12 were excluded because of hyperparathyroidism or coexisting malignancies; thus, 256 patients were included in the study. Most patients (82%) had mild hypercalcemia. Severity of hypercalcemia was associated with disease stage (P = 0.0019), use of hypercalcemia treatment (P < 0.0001), and survival duration (P < 0.0001). The median survival duration of patients who had not been treated for hypercalcemia was 432 days compared with 106 days in patients who had been treated. The shorter survival duration of treated patients seems to result from their disease status and hypercalcemia severity rather than whether they were treated for hypercalcemia.

Conclusions:

Moderate and severe hypercalcemia is associated with poorer survival duration in gynecologic malignancy patients. Early detection and treatment of hypercalcemia in these patients may prolong survival. To our knowledge, this is the first study of hypercalcemia in patients with general gynecologic malignancy.

Development of a low-dose anti-resorptive drug regimen reveals synergistic suppression of bone formation when coupled with disuse

Safe and effective countermeasures to spaceflight-induced osteoporosis are required to mitigate the potential for mission-critical fractures and ensure long-term bone health in astronauts. Two anti-resorptive drugs, the bisphosphonate zoledronic acid (ZOL) and the anti-receptor activator of NF-kappaB ligand protein osteoprotegerin (OPG), were investigated to find the minimum, comparable doses that yield a maximal increase in bone quality, while minimizing deleterious effects on turnover and mineralization. Through a series of five trials in normally loaded female mice (n = 56/trial), analysis of trabecular volume fraction and connectivity using microcomputed tomography, along with biomechanical testing, quantitative histomorphometry, and compositional analysis, was used to select 45 microg/kg ZOL and 500 microg/kg OPG as doses that satisfy these criteria. These doses were then examined for their ability to mitigate bone loss following short-term unloading through hindlimb suspension (HLS). Seventy-two mice were prophylactically administered ZOL, OPG, or PBS and assigned to loaded control or 2-wk HLS groups (n = 12 for each of 6 groups). Both anti-resorptives were able to preserve trabecular microarchitecture and femoral elastic and maximum force in HLS mice (+30-40% ZOL/OPG vs. PBS). In HLS mice, anti-resorptive dosing reduced resorption perimeter at the femoral endocortical surface by 30% vs. PBS. In loaded control mice, anti-resorptives produced no change in bone formation rate; however, reductions in bone formation rate brought about by HLS were exacerbated by anti-resorptive treatment, suggesting synergistic inhibition of osteoblasts during disuse. Refined anti-resorptive dosing will tend to target countermeasures to the period of disuse, resulting in faster recovery and less adverse effects for astronauts.

Acute phase response and mineral status following low dose intravenous zoledronic acid in children

INTRODUCTION

Previous reports have shown a high frequency of hypocalcaemia and flu-like symptoms following an initial first zoledronic acid dose of 0.02-0.025 mg/kg in children.

METHODS

We systematically evaluated the mineral status and symptomatology of 63 children with a variety of bone disorders treated with an initial zoledronic acid dose of 0.0125 mg/kg. The Mann-Whitney U test, chi-squared test and Fisher's exact test were used as appropriate.

RESULTS

0.0125 mg/kg zoledronic acid reduced the incidence and intensity of hypocalcaemia but not the incidence of the flu-like symptoms compared to higher doses. Within the low dose cohort, flu-like symptoms were associated with an acute inflammatory response. Children who became hypocalcaemic received a higher dose in relation to their body mass index and body surface area.

CONCLUSION

Reducing the initial zoledronic acid dose in children decreased the incidence of hypocalcaemia and thus improved safety. Dosing on the basis of body mass index or body surface area instead of body weight may further reduce the incidence of hypocalcaemia.

Skeletal metastases in non-small cell lung cancer: a retrospective study

BACKGROUND

The skeleton is one of the most common sites of metastasis in patients with advanced cancer. Bone metastases often cause SREs (skeletal-related events). Despite advances in the treatment of primary lung cancer, SREs still affect many patients. Therefore, we planned a retrospective study to investigate the clinical impact of SREs, and to compare differences in the therapeutic outcome between patients with and without skeletal metastases or SRE.

PATIENTS AND METHODS

We retrospectively investigated the charts of all 259 patients with non-small cell lung cancer (NSCLC) who consulted the Department of Medical Oncology at Kinki University School of Medicine between February 2002 and January 2005. We assessed their TNM stage, presence of skeletal metastases (on bone scintigraphy, MRI, and plain X-ray films), and outcome parameters such as SREs, analgesic use, and survival.

RESULTS

A total of 70 patients (30.4%) were found to have skeletal metastases during their clinical course and 35 patients (50%) out of all 70 patients had SREs. Among 135 stage IV patients, a total of 56 (41%) had skeletal metastases, and 25 of these 56 patients (45%) had SREs. The most common SREs were the need for radiotherapy (34.3%) and hypercalcemia (20%). Patients with SREs tended to have worse survival, while no significant difference of survival was observed between patients with and without skeletal metastases.

CONCLUSION

It seems to be important to prevent SREs during the treatment of NSCLC, so further studies evaluating bisphosphonates in combination with chemotherapy are warranted.

Effect of zoledronic acid on markers of bone turnover and mineral density in osteoporotic patients with beta-thalassaemia

Osteoporosis has emerged as an important cause of morbidity in patients with thalassemia major. Studies regarding the efficacy of bisphosphonates in thalassemia-induced osteoporosis have yielded conflicting results. We performed this prospective study to evaluate the efficacy of zoledronic acid in osteoporotic patients with thalassemia major. Patients, 29, were given 1 mg zoledronic acid intravenously every 3 months for a total of four doses. Twenty age- and sex-matched healthy blood donors served as controls. Before each infusion and 3 months after the last infusion, we determined serum levels of osteoprotegerin (OPG), N-terminal cross-linking telopeptide of type I collagen (NTX), osteocalcin (OC) and insulin-like growth factor 1 (IGF-1). Bone mineral density (BMD) of the lumbar spine was measured at baseline and after the treatment's completion. At baseline, OPG did not differ significantly between patients and controls (p=0.2), NTX were higher in patients although not significantly (p=0.139), whereas, OC levels were significantly higher and IGF-1 levels significantly lower in patients than in controls (p<0.001 and p<0.006, respectively). Zoledronic acid administration resulted in a significant decrease in NTX, OC and IGF-1 (p<0.05, p<0.001 and p<0.05, respectively) and in a significant increase in OPG and BMD (p<0.05 for both comparisons). The change in NTX, osteocalcin and IGF-1 became significant as early as 3 months after the first administration of zoledronic acid, while the change in OPG reached significance only after three infusions. Our study supports the effectiveness of bisphosphonates in the treatment of thalassemia-induced osteoporosis.

The beneficial effect of intravenous zoledronic acid therapy following an acute stroke in rats

PURPOSE

Changes of bone metabolism begin from the initial stages of stroke; therefore, early prevention of these changes has become important. The most appropriate target for preventive therapy is to restrict the profound increase in osteoclastic bone resorption that occur soon after stroke. Oral bisphosphonates, which selectively target osteoclasts and their precursors, are appropriate drugs, but dysphagia or drowsiness after acute stroke can make it difficult to easily administer these compounds to stroke patients. The intravenous (IV) administration of bisphosphonates is an alternative method that can overcome these limitations. In order to determine the effect of IV bisphosphonates at the initial stages of stroke for preventing bone loss, an experiment using ischemic stroke rats was conducted.

METHODS

Female Sprague-Dawley rats (n = 100) were randomly divided into four separate groups; sham surgery and vehicle-treated group (sham-vehicle), stroke and vehicle-treated group (stroke-vehicle), stroke with low-dose zoledronic acid treatment group (stroke-low) and stroke with high-dose zoledronic acid treatment group (stroke-high). Permanent occlusion of the left middle cerebral artery was performed, resulting in right hemiplegia. The bone mineral density (BMD) of the 4th and 5th lumbar vertebrae and the femur on the stroke side were measured in vivo on the day before stroke and on the 10th and 21st day after stroke. The osteocalcin and carboxy-terminal telopeptide blood levels were measured on the 10th and 21st day after stroke. The BMD of the excised proximal tibia and the maximum load of femoral neck were measured on the 21st day after stroke.

RESULTS

After 21 days of stroke, the BMD of the lumbar vertebrae, femur, and excised tibia and the maximum load of the femoral neck in the sham-vehicle, stroke-low, and stroke-high groups were significantly higher than those in the stroke-vehicle group (P < 0.05). The carboxy-terminal telopeptide levels in the sham-vehicle and stroke-high groups were significantly lower than those in the stroke-vehicle group (P < 0.05).

CONCLUSION

The results suggest that IV zoledronic acid treatment might prevent bone loss during the initial stages of stroke.

ANTI-INFLAMMATORY AND ANTI-NOCICEPTIVE ACTIVITY OF RISEDRONATE IN EXPERIMENTAL PAIN MODELS IN RATS AND MICE

1. The antinociceptive effect of risedronate in experimental pain models in rats and mice was investigated in the present study. 2. Rats received zymosan intra-articularly (i.art.) into the right knee joint and the nociceptive response was assessed using the articular incapacitation test. Joint washouts were used for determining cell influx, tumour necrosis factor (TNF)-alpha and leukotriene (LT) B4 levels. 3. Mice received either zymosan (1 mg) or acetic acid (0.6%) i.p. and the nociceptive response was measured as the number of writhings between 0 and 30 min after the stimuli. Control animals received i.p. injections of saline. 4. Groups were pretreated with risedronate (5-500 microg/kg, s.c.) and compared with vehicle (saline)-treated (NT) animals. One group of rats was cotreated with the micro-opioid receptor antagonist naloxone (2 mg/kg, s.c.) prior to risedronate, followed by 1 mg zymosan i.art. 5. Risedronate, at 100 and 500 microg/kg, significantly and dose-dependently inhibited the nociceptive response in the writhings test (P < 0.05), inhibiting responses to acetic acid by 65.4 and 49.2%, respectively, and to zymosan by 72.9 and 71.9%, respectively. 6. Pretreatment with risedronate also significantly (P < 0.05) and dose-dependently inhibited the articular incapacitation in zymosan-arthritis. 7. Risedronate, at 50 microg/kg, significantly inhibited TNF-alpha release as compared with the NT group (39.4 +/- 9.8 vs 145.6 +/- 43.3 pg/mL TNF-alpha, respectively). 8. Risedronate, at 50 and 100 microg/kg, significantly inhibited LTB4 release into the joints compared with the NT group (2883.1 +/- 73.2, 1911.5 +/- 205.3 and 4709.9 +/- 237.2 pg/mL, respectively). These effects of risedronate were associated with a significant reduction in the inflammatory cell infiltration. 9. Cotreatment with risedronate and naloxone did not reverse the antinociceptive effects of risedronate in zymosan-arthritis. 10. This is the first demonstration that risedronate displays intrinsic antihypernociceptive activity. This effect is associated with reduced cell infiltration and inhibition of TNF-alpha and LTB4 release and is not linked to an endogenous opioid-release mechanism.

[Hypercalcemia of malignancy: clinical features, diagnosis and treatment]

Hypercalcemia associated with malignancies is reported in up to 20 to 30% of patients with cancer during the course of the disease, and points to a poor prognosis. Symptoms related to the central nervous system, as progressive mental impairment, stupor and coma, predominate. Alterations in kidney function (water-concentrating defect leading to polyuria) and gastrointestinal tract (anorexia, nausea, vomiting) corroborate to dehydration and a further increase in serum calcium. Cancer-induced hypercalcemia may be classified as: 1) local osteolytic hypercalcemia (LOH), due to marked increase in osteoclastic bone resorption in areas surrounding the malignant cells within the marrow space; 2) humoral hypercalcemia of malignancy, caused by the secretion of parathyroid hormone-related protein (PTHrP) by the malignant tumor; 3) ectopic hyperparathyroidism; 4) 1,25(OH)2 D-secreting tumors. Adequate control of hypercalcemia is necessary to give the patient time to respond to anti-cancer therapy. Volume expansion with saline will correct dehydration, improve glomerular filtration and increase urinary calcium excretion, which may be further stimulated by loop diuretics. Intravenous bisphosphonates are the most effective agents to control hypercalcemia, as they block osteoclastic osteolysis and also have antitumoral effects, decreasing bone metastases. New approaches to control the skeletal manifestations of malignancies are anti-PTHrP and anti-RANKL antibodies, osteoprotegerin, and also proteasome inhibitors in the case of multiple myeloma.

Current management strategies for hypercalcemia

The two most common causes of hypercalcemia are primary hyperparathyroidism and neoplastic disease. Parathyroidectomy is the only curative intervention for the former condition. In the rare cases of patients with primary hyperparathyroidism who present with clinical symptoms due to their hypercalcemia, pharmacological treatment may be required. Fluid repletion and intravenous (IV) administration of bisphosphonates are recommended in the literature. Calcium receptor agonists (calcimimetic agents) are at the present time only available for use within clinical trials. Cancer patients usually present with symptoms of hypercalcemia. Rapid institution of antihypercalcemic treatment is essential in preventing life-threatening deterioration. Fluid repletion and administration of bisphosphonates are the treatment mainstays in hypercalcemia of malignancy. Five bisphosphonates are currently licensed in Europe for treatment of tumor-associated hypercalcemia: etidronate, clodronate, pamidronate, ibandronate, and zoledronate. In the US, pamidronate and zoledronate are licensed for use in this indication. Bisphosphonates containing nitrogen atoms (e.g. pamidronate, ibandronate, and zoledronate) are more potent than those without (e.g. etidronate, clodronate, and tiludronate). In patients with malignant hypercalcemia, the efficacy of the individual bisphosphonate depends on dose administered and initial serum calcium concentration. At present, pamidronate has been studied in the greatest number of investigations and in the largest number of patients. In the literature, the efficacy of pamidronate in restoring normocalcemia ranges between 40% and 100%, depending on the dose used and baseline serum calcium concentration. More recently, one study reported that pamidronate was inferior to zoledronate. In this study, the duration of response was also longer in the two zoledronate groups (30 and 40 days) than in the pamidronate group (17 days). The most serious adverse events of bisphosphonates concern renal function. Increases in serum creatinine levels have been more frequently reported following treatment of tumor-associated hypercalcemia with etidronate (8%) and clodronate (5%) than with the nitrogen-containing bisphosphonates pamidronate (2%) and ibandronate (1%). The frequency of increases in serum creatinine levels following treatment with zoledronate is difficult to estimate. Administration of the nitrogen-containing bisphosphonates has been associated with transient (usually mild) fever, lymphocytopenia, malaise, and myalgias. These events occur within 36 hours of the first dose and are self-limiting. Hypocalcemia occurs in up to 50% of patients treated with bisphosphonates for hypercalcemia of malignancy, although symptomatic hypocalcemia is rare. The toxicity and low efficacy of plicamycin (mithramycin) mean that use of this agent should be restricted to patients with hypercalcemia of malignancy who fail to respond to IV bisphosphonates. Calcitonin is characterized by good tolerability but poor efficacy in normalizing the serum calcium level. However, a major advantage of calcitonin is the acute onset of the hypocalcemic effect, which contrasts with the delayed but more pronounced effect of bisphosphonates. Combination calcitonin and bisphosphonate treatment may therefore be of value when rapid reduction of serum calcium is warranted. Gallium nitrate may be a valuable treatment for hypercalcemia of malignancy. It is characterized by high efficacy and few adverse events apart from renal toxicity (10% of cases). However, data are very limited and further trials are necessary.

Short-term zoledronic acid treatment increases bone mineral density and marrow clonogenic fibroblast progenitors after allogeneic stem cell transplantation

Although osteoporosis is a relatively common complication after allogeneic stem cell transplantation, the role of bisphosphonates in its management has not yet been completely established. Thirty-two patients who underwent allogeneic stem cell transplantation were prospectively evaluated for bone mineral density (BMD) at the lumbar spine (LS) and femoral neck (FN) after a median period of 12.2 months. Then, 15 of the patients with osteoporosis or rapidly progressing osteopenia (bone loss > 5%/yr) received three monthly doses of 4 mg zoledronic acid iv. Fifteen patients were followed up without treatment, and all 30 patients were reevaluated after 12 months for BMD and bone turnover markers. By using enriched mesenchymal stem cells in the colony-forming units fibroblast (CFU-F) assay, we evaluated the osteogenic stromal lineage. This procedure was performed in both groups of patients at study entry and after 12 months. The average BMD loss was 3.42% at LS and 3.8% at FN during a 1-yr longitudinal evaluation in 32 patients. Subsequently, BMD increased at both LS and FN (9.8 and 6.4%, respectively) in the zoledronic acid-treated cohort. Hydroxyproline excretion decreased, and serum bone-specific alkaline phosphatase increased significantly, whereas serum osteocalcin increase did not reach the limit of significance. A significant increase in CFU-F growth in vitro was induced by in vivo zoledronic acid administration. In the untreated group, no significant change was observed in bone turnover markers, LS BMD (-2.1%), FN BMD (-2.3%), and CFU-F colony number. In conclusion, short-term zoledronic acid treatment consistently improved both LS and FN BMD in transplanted patients who were at high risk for fast and/or persistent bone loss, partly by increasing the osteogenic progenitors in the stromal cell compartment.

Zoledronic acid inhibits visceral metastases in the 4T1/luc mouse breast cancer model

PURPOSE

It is established that bisphosphonates (BPs), specific inhibitors of osteoclasts, have beneficial effects on bone metastases of breast cancer. In addition, recent studies have reported that BPs have anticancer effects and suppress visceral metastases, too. However, the results of clinical studies are still conflicting. In the present study, we examined the effects of the BP zoledronic acid (ZOL), one of the most potent BPs currently available, on visceral metastases of breast cancer using an animal model in which mouse breast cancer cells 4T1/luc implanted at the orthotopic mammary fat pad spontaneously metastasize to multiple organs including bone, lung, and liver in female BALB/c mice.

EXPERIMENTAL DESIGN AND RESULTS

The 4T1/luc-bearing mice received single or four i.v. injections of ZOL (0.5 or 5 microg/mouse) during the whole experimental period. Bone metastases were reduced by the ZOL treatment. More importantly, ZOL significantly suppressed lung and liver metastases. Furthermore, ZOL prolonged overall survival of the tumor-bearing mice. Of interest, apoptosis in 4T1/luc cells colonized in bone was increased by ZOL; however, those in lung were not changed. In vitro studies demonstrated that ZOL inhibited cell migration and invasion and promoted apoptosis of 4T1/luc cells.

CONCLUSIONS

These results are consistent with the notion that ZOL affects breast cancer metastasis to visceral organs as well as bone. These effects of ZOL may be attributable to inhibition of migration and invasion of breast cancer cells. Clinical relevance of our experimental results needs to be determined in breast cancer patients with visceral metastases.

Short-term safety assessment in the use of intravenous zoledronic acid in children

The clinical side effects of the potent new bisphosphonate zoledronic acid in children are unknown. In this study of 34 children with various bone disorders, the frequency of postinfusion flu-like illness, hypocalcemia, and hypophosphatemia was 85%, 74%, and 82%, respectively. No renal side effects were detected after up to 3 consecutive infusions.