Profiling the safety and tolerability of bisphosphonates

Effects of Systemic or Local Administration of Zoledronate on Implant Osseointegration: A Preclinical Meta-Analysis

Objective

This study aims to investigate the effect of systemically administrated zoledronate on bone-implant fixation in animal models.

Methods

We searched MEDLINE, Embase, and EBSCO for studies that explore the role of systemic or local zoledronate delivery in implant osseointegration in animal models. The Review Manager software was used to analyze selected studies by using the weighted mean difference random-effects model. Analytical data are mainly about bone ingrowth, such as bone-to-implant contact (BIC), bone volume/total volume (BV/TV), and bone area.

Results

Twenty studies were selected from 182 publications. The mean quality score was 18/20 for all of the 20 studies (κ = 0.9). Despite differences in protocols, these studies showed consistent improvement of implant osseointegration with zoledronate administration. In addition, the osteoporotic animal model, systemic or local administration, sufficient drug dosage, and sample follow-up time were correlated with improved outcomes.

Conclusion

Systematic administration of zoledronate could improve the osseointegration of orthopedic implant in animal models. Results of this meta-analysis should be interpreted cautiously because of the inherent differences between preclinical and clinical subjects. For the local administration, there is a similar trend as well, but the results need to be confirmed and complemented with further analyses.

Zoledronic acid administration failed to prevent bone loss at the knee in persons with acute spinal cord injury: an observational cohort study

After acute spinal cord injury (SCI), rapid depletion of the sublesional skeleton occurs, particularly at the distal femur and proximal tibia. Subsequently, fragility fractures of the knee may occur. We determined the efficacy of zoledronic acid to prevent sublesional bone mineral density (BMD) loss at 6 and 12 months after acute SCI. Thirteen subjects with acute motor-complete SCI were prospectively studied: 6 patients received zoledronic acid (5 mg) and 7 subjects did not receive the drug (controls). Zoledronic acid was administered intravenously within 16 weeks of acute injury. Areal BMD was performed by dual energy X-ray absorptiometry at baseline, 6, and 12 months after administration of drug. The treatment group demonstrated sparing of BMD at the total hip at month 6 (p < 0.0006) and at month 12 (p < 0.01). In contrast to the findings at the hip, the treatment group had a greater loss of BMD compared to the control group at the distal femur and proximal tibia at month 6 (-7.9% ± 3.4 vs.-2.7% ± 5.0, respectively, p = 0.054; and -10.5% ± 6.4 vs. -4.8% ± 6.8, respectively, p = NS) and at month 12 (-18.5% ± 3.9 vs. -8.4% ± 7.2, respectively, p = 0.01; and -20.4% ± 8.8 vs.-7.9% ± 12.3, respectively, p = 0.06). A single dose of zoledronic acid administered soon after acute SCI reduced the %BMD loss at the hip, but appeared to have no effect to prevent %BMD loss at the knee, the site where fracture risk is greatest in persons with SCI.

The biocompatibility of calcium phosphate cements containing alendronate-loaded PLGA microparticles in vitro

The composite of poly-lactic-co-glycolic acid (PLGA) and calcium phosphate cements (CPC) are currently widely used in bone tissue engineering. However, the properties and biocompatibility of the alendronate-loaded PLGA/CPC (APC) porous scaffolds have not been characterized. APC scaffolds were prepared by a solid/oil/water emulsion solvent evaporation method. The morphology, porosity, and mechanical strength of the scaffolds were characterized. Bone marrow mesenchymal stem cells (BMSCs) from rabbit were cultured, expanded and seeded on the scaffolds, and the cell morphology, adhesion, proliferation, cell cycle and osteogenic differentiation of BMSCs were determined. The results showed that the APC scaffolds had a porosity of 67.43 ± 4.2% and pore size of 213 ± 95 µm. The compressive strength for APC was 5.79 ± 1.21 MPa, which was close to human cancellous bone. The scanning electron microscopy, cell counting kit-8 assay, flow cytometry and ALP activity revealed that the APC scaffolds had osteogenic potential on the BMSCs in vitro and exhibited excellent biocompatibility with engineered bone tissue. APC scaffolds exhibited excellent biocompatibility and osteogenesis potential and can potentially be used for bone tissue engineering.

Clinical efficacy and safety of pamidronate therapy on bone mass density in early post-renal transplant period: a meta-analysis of randomized controlled trials

Introduction

The overall effect of pamidronate on bone mass density (BMD) in the early renal transplant period varies considerably among studies. The effects of pamidronate on graft function have not been determined.

Materials and Methods

A comprehensive search was conducted in PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL) and Embase independently by two authors. Randomized controlled trials of pamidronate evaluating bone loss in the first year of renal transplantation were included. Methods reported in the “Cochrane Handbook for Systematic Reviews of Interventions 5.0.2” were used to evaluate changes of lumbar spine and femoral neck BMD, and serum creatinine, calcium and intact parathyroid hormone (iPTH) levels. Fixed or random effect models were used as appropriate.

Results

Six randomized trials evaluating 281 patients were identified. One hundred forty-four were treated with pamidronate and 137 were control patients. Administration of pamidronate was associated with significant reduction of bone loss in the lumbar spine, compared to the control group (standardized mean difference (SMD)  = 24.62 [16.25, 32.99]). There was no difference between the pamidronate treated and control femoral neck BMD (SMD  = 3.53 [−1.84, 8.90]). A significant increase in the serum creatinine level of the intervention group was seen, compared to the control group. The serum calcium and iPTH of the pamidronate and control groups were not different after 1 year (serum creatinine: SMD  = −3.101 [−5.33, −0.89]; serum calcium: SMD  = 2.18 [−0.8, 5.16]; serum iPTH: SMD  = 0.06 [−0.19, 0.31]). Heterogeneity was low for serum calcium and iPTH and high for serum creatinine.

Conclusions

This meta-analysis demonstrated the beneficial clinical efficacy of pamidronate on BMD with no association with any alteration in graft function during the first year of renal transplantation. Significant heterogeneity precludes the conclusion of the relationship between serum creatinine and pamidronate.

Adverse events across generations of bone-modifying agents in patients with solid tumor cancers reported in Phase III randomized trials

AIMS

The objective of this study is to compare adverse events experienced among different bone-modifying agents.

METHODS

A literature search was conducted to identify Phase III bisphosphonate and bone-modifying agent trials reporting adverse effects. Thirty-seven adverse events of interest were identified for six different treatment options. Weighted linear regression modeling was performed on the adverse event proportions with treatment groups, normalized through applying natural log transformations.

RESULTS

There were significant differences in adverse events of vomiting (p = 0.045) and osteonecrosis of the jaw (p = 0.017), and combined item events of nausea/vomiting (p = 0.048), hematological and lymphatic system toxicities (p = 0.020), and any respiratory system problem (p = 0.023) between bone-modifying agent and placebo trials. The significant toxicities were observed even after adjusting for the two confounding factors of age and primary cancer site.

CONCLUSION

While adverse effects are consistently experienced more frequently in patients receiving bone-modifying agents when compared with placebos, we find that the majority of individual side effects are not significantly more frequent in patients receiving bone-modifying agents compared with placebo.

Effects of zoledronic acid on physiologic bone remodeling of condylar part of TMJ: a radiologic and histomorphometric examination in rabbits

Objective. The purpose of the present study is to evaluate the effects of systemically administered zoledronic acid (ZA) on the physiological bone remodeling and the microarchitectural parameters of the condylar part of TMJ in a rabbit model. Study Design. Thirty skeletally mature male New Zealand white rabbits were randomly divided into two groups. The experimental group was administered an intravenous, single dose of 0.1 mg/kg ZA diluted with 15 mL of saline in a 15-minute perfusion with an infusion pump. The control group was administered only saline infusion for 15 minutes. All rabbits were sacrificed on the 21st postoperative day. Radiodensitometric and histomorphometric examinations were performed on the harvested mandibular condyles. The data were analyzed statistically. Results. Radiodensitometric findings showed that ZA treatment resulted in a significant increase in the mineralization of mandibular condyle. This result was supported by the histomorphometric findings. Conclusion. The present study has revealed that a temporary delay in the physiological bone remodeling using single dose of ZA increases bone mineral content and makes the microarchitecture of the mandibular condyle more compact. These effects may be regarded as base data and considered in numerous clinical situations including TMJ.

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.

Optimising the use of bone-targeted agents in patients with metastatic cancers: a practical guide for medical oncologists

Bone metastases can be associated with a significant worsening of patient morbidity and mortality. Bisphosphonates have been extensively researched and shown to delay the onset and reduce the incidence of complications from bone metastases. The most commonly used bisphosphonates are intravenous pamidronate, intravenous ibandronate, intravenous zoledronic acid and oral/intravenous clodronate. Several bone-targeted agents with innovative mechanisms of action are currently being developed. These include receptor activator of nuclear factor-kB ligand (RANKL) inhibitors, CCR1 inhibitors, Src inhibitors, DKK1-neutralising antibodies, activin antagonists and endothelin-1 inhibitors. In an era of individualised medicine, oncologists are being faced with an increasing number of questions when dealing with bone-targeted agents. These questions not only include the choice of which drug to use (i.e. bisphosphonates or RANKL inhibitor) but also the best treatment strategy to use. This review will provide medical oncologists with a practical guide to the use of bone-targeted agents.

Pharmacology of bisphosphonates

Four decades of preclinical and clinical research of the pharmacology of bisphosphonates have generated data and concepts that have considerably improved their clinical use. However, despite this progress several pharmacological aspects relevant to bisphosphonate action on bone are still incompletely understood. This is mainly due to the complex, unique pharmacological properties of bisphosphonates. We review here the pharmacokinetic and pharmacodynamic data of bisphosphonates that are relevant for their clinical application and for the potential choice of a given compound, focusing on uncertainties that still exist.

Effects of zoledronic acid on healing of mandibular fractures: an experimental study in rabbits

PURPOSE

The purpose of the present study was to evaluate the effects of systemically administered zoledronic acid (ZA) on mandibular fracture healing in a rabbit model using radiodensitometric, biomechanical, histologic, and histomorphometric methods.

MATERIALS AND METHODS

A total of 36 skeletally mature male New Zealand white rabbits were used. The rabbits were randomly divided into 2 groups. A mandibular corpus fracture was created experimentally in all 36 rabbits. The experimental group was administered an intravenous, single dose of 0.1 mg/kg ZA, and the control group was administered only saline infusion during the procedure. All rabbits were sacrificed on the 21st postoperative day. Digital radiodensitometric analysis, a 3-point bending test, and histologic and histomorphometric examinations were performed on the harvested hemimandibles. The data were analyzed statistically.

RESULTS

Biomechanical testing data showed that ZA treatment resulted in a significant increase in the healed bone strength. This result was supported by the radiologic, histologic, and histomorphometric findings.

CONCLUSIONS

The results of the present study have revealed that systemic administration of ZA accelerates and improves the bone healing of mandibular fractures.

Use of bisphosphonates among women and risk of atrial fibrillation and flutter: population based case-control study

OBJECTIVE

To assess the association between atrial fibrillation and flutter and use of bisphosphonates for osteoporosis among women.

DESIGN

Population based case-control study, using medical databases from Denmark.

SETTING

Northern Denmark.

PARTICIPANTS

13 586 patients with atrial fibrillation and flutter and 68 054 population controls, all with complete hospital and prescription history.

MAIN OUTCOME MEASURE

Adjusted relative risk of atrial fibrillation and flutter.

RESULTS

435 cases (3.2%) and 1958 population controls (2.9%) were current users of bisphosphonates for osteoporosis. Etidronate and alendronate were used with almost the same frequency among cases and controls. The adjusted relative risk of current use of bisphosphonates compared with non-use was 0.95 (95% confidence interval 0.84 to 1.07). New users had a relative risk of 0.75 (95% confidence interval 0.49 to 1.16), broadly similar to the estimate for continuing users (relative risk 0.96, 95% confidence interval 0.85 to 1.09). The relative risk estimates were independent of number of prescriptions and the position of the atrial fibrillation and flutter diagnosis in the discharge record, and were similar for inpatients and outpatients.

CONCLUSION

No evidence was found that use of bisphosphonates increases the risk of atrial fibrillation and flutter.

Treatment with zoledronic acid ameliorates negative geometric changes in the proximal femur following acute spinal cord injury

Acute spinal cord injury is associated with rapid bone loss and an increased risk of fracture. In this double-blind, randomized, placebo-controlled trial, 17 patients were followed for 1 year after administration of either 4 or 5 mg of zoledronic acid or placebo. Bone mineral density (BMD) and structural analyses of the proximal femur were performed using the hip structural analysis program at entry, 6 months, and 12 months. The 17 subjects completed 12 months of observation, nine receiving placebo and eight zoledronic acid. The placebo group showed a decrease in BMD, cross-sectional area, and section modulus and an increase in buckling ratio at each proximal femur site at 6 and 12 months. Six months after zoledronic acid, BMD, cross-sectional area, and section modulus increased at the femoral neck and intertrochanteric regions and buckling ratio decreased consistent with improved bone stability. However, at 12 months, the femoral narrow-neck values declined to baseline. In contrast to placebo, the intertrochanteric region and femur shaft were maintained at or near baseline through 12 months in the zoledronic acid-treated group. Urine N-telopeptide excretion was increased at baseline and declined in both the placebo and treatment groups during the 12 months of observation. We conclude that a single administration of zoledronic acid will ameliorate bone loss and maintain parameters of bone strength at the three proximal femur sites for 6 months and at the femur intertrochanteric and shaft sites for 12 months.

Bisphosphonate modulates morphological and mechanical properties in distraction osteogenesis through inhibition of bone resorption

Despite the general clinical acceptance of distraction osteogenesis and much attention to bone formation in this method, little is recognized about activated bone resorption in the regenerated bone. The purpose of this study was to demonstrate the simultaneously activated bone resorption with activated bone formation and to investigate the role and efficacy of bisphosphonate in distraction osteogenesis. Left tibiae of 54 immature rabbits were lengthened for 3 weeks at a rate of 0.7 mm/day after a 1-week lag. Regenerated bone was quantitatively investigated by radiographic bone density, bone histomorphometry, and three-point bending testing. Animals received either vehicle or nitrogen-containing bisphosphonate (N-BP), YM529/ONO5920 at doses of 0.4 mg/kg/w or 0.004 mg/kg/w for 6 weeks. Regenerated bone of the vehicle group showed a radiologically characteristic zone structure containing the osteopenic zones adjacent to the sclerotic zones. The regenerated bone of the 0.4-mg/kg/w group showed no osteopenic zones during the course and eventually became homogeneously radiodense. The bone volume corresponding to the osteopenic zone of this group was 5.6-fold greater compared with that of the vehicle group. The lengthened bone strength of this group was 3.3-fold greater in ultimate force than that of the vehicle group and equivalent to the contralateral tibia. The 0.004-mg/kg/w group had no substantial differences compared with the vehicle group, despite radiological enhancement of the mineralized front as well as somewhat delayed bone resorption. These results demonstrate that not only bone formation but also bone resorption is highly activated in the regenerated bone, implying high bone turnover. Sufficient N-BP caused a notable modulation in morphological properties of the regenerated bone through inhibition of highly activated bone resorption and eventually increased mechanical properties.

Modulation of TNFalpha, a determinant of acute toxicity associated with systemic delivery of first-generation and helper-dependent adenoviral vectors

Understanding the determinants of the host innate immune response to systemic administration of adenoviral (Ad) vectors is critical for clinical gene therapy. Acute toxicity occurs within minutes to hours after vector administration and is characterized by activation of innate immune responses. Our data indicate that in mice, indicators of vector toxicity include elevations of cytokine levels, liver transaminase levels and thrombocytopenia. To discern potential targets for blunting this host response, we evaluated genetic factors in the host response to systemically administered first-generation Ad vectors (FGV) and helper-dependent Ad vectors (HDV) containing beta-galactosidase expression cassettes. A preliminary screen for modulation of vector-induced thrombocytopenia revealed no role for interferon-gamma, mast cells or perforin. However, vector-induced thrombocytopenia and interleukin 6 (IL-6) expression are less evident in tumor necrosis factor alpha (TNFalpha)-deficient mice. Moreover, we also demonstrated that TNFalpha blockade via antibody or huTNFR:Fc pretreatment attenuates both thrombocytopenia (>40% increase in platelet count) and IL-6 expression (>80% reduction) without affecting interleukin 12 , liver enzymes, hematological indices or vector transduction in a murine model. Our data indicate that the use of HDV, in combination with clinically approved TNFalpha immunomodulation, may represent an approach for improving the therapeutic index of Ad gene therapy for human clinical trials.

Ibandronate: efficacy in the treatment of metastatic bone disease

Ibandronate is a bisphosphonate treatment for metastatic bone disease. In Phase III trials in breast cancer patients, intravenous and oral formulations of ibandronate lowered the incidence of skeletal-related events, reduced metastatic bone pain scores throughout 2 years of treatment, and had significant positive effects on patient quality of life, demonstrating its efficacy in this condition. Recent pilot studies in other primary cancers suggest that a loading dose of ibandronate may relieve severe or opioid-resistant metastatic bone pain. In safety analyses, ibandronate was well tolerated with a safety profile comparable to placebo. Ibandronate therefore represents a treatment choice with documented efficacy and safety in metastatic bone disease from breast cancer.

A single systemic dose of pamidronate improves bone mineral content and accelerates restoration of strength in a rat model of fracture repair

Complications in fracture repair that lead to a delay in union remain clinically problematic. We believe that unwanted pre-mature catabolism of the healing callus, for example, in stress shielded situations, diminishes the rate at which strength is restored in bone repair and possibly leads to delayed union. We hypothesized that a single systemic dose of a nitrogen-containing bisphosphonate (N-BP) would increase bone mineral content (BMC), volume, and mechanical strength of union in fracture repair. We also set out to investigate local delivery to assess whether systemic exposure could be eliminated, due to concerns of bisphosphonate dosing of non-target organs. After an open osteotomy fixed with a K wire, 40 12-week old Wistar male rats were divided into four groups of 10: saline control, bolus systemic subcutaneous injection of pamidronate (3 mg/kg), local low dose of pamidronate (0.1 mg), and a local high dose of pamidronate (1.0 mg). Rats were sacrificed 6 weeks post-operatively. Operated and non-operated femora underwent radiographic evaluation, quantitative computer tomography, and biomechanical testing in torsion. The growth plates and metaphyses of the tibia of the non-operated side were assessed for evidence of systemic exposure in the local groups. Significant increases in callus BMC and volume of the bolus systemic dose group were found compared to the saline control (p< or =0.05). Further, the strength of the systemic dose callus was increased by 60% from 0.35 Nm (+/-0.11) for the saline control callus to 0.56 Nm (+/-0.25) for the systemic group (p=0.05). Local treatment did not result in increased strength. The contralateral tibial growth plates of the local groups showed evidence of systemic exposure by the presence of retained primary spongiosa. This study confirms that a single perioperative systemic dose of pamidronate leads to significant increases in the BMC, volume, and strength of healing fractures in rats, making single dose N-BP therapy an appealing candidate for further examination in fracture repair.

Management of bone metastases in cancer: a review

The presence of bone metastases is indicative of disseminated disease and typically indicates a short-term prognosis in cancer patients. Palliation of symptoms is the primary goal of therapy, with multidisciplinary efforts yielding the best results. New classes of drugs, such as bisphosphonates that significantly increase the time to first skeletal-related event (SRE), represent useful tools for the treatment of bone metastases. While the optimal duration of therapy needs to be defined, there is clinical benefit derived from the use of this class of agents. A potential role for bisphosphonates in the prevention of bone metastases is under current evaluation in clinical trials encompassing different solid tumor types. In combination with ongoing clinical trials, basic research to identify potential novel targets in the tumor cells-bone microenvironment will further define future strategies in the treatment of bone metastases.

Strategies to Prevent Chemotherapy-Induced Bone Loss in Women with Breast Cancer

Treatment-induced osteoporosis is an increasing problem for women diagnosed with breast cancer. As more women receive adjuvant endocrine therapy and chemotherapy, and breast cancer survival improves, the impact of cancer treatment on bone health and the morbidity associated with chemotherapy-induced bone loss becomes more of a significant medical concern. Endocrine agents like aromatase inhibitors and luteinizing hormone-releasing hormone agonists decrease the production of ovarian and adrenal estrogens and are widely used in the adjuvant and metastatic settings for treatment of women with hormone receptor-positive breast cancer. Estrogen is important for bone health. It stimulates osteoblasts and maintains bone integrity. As bone density decreases, the risk of fracture increases. This can include fractures of the wrist, femur, and vertebrae. Several potent bisphosphonates have been developed to prevent or treat cancer treatment-induced bone loss.