Effects of five daily 1 h infusions of alendronate in Paget's disease of bone

Drug treatment strategies for Paget's disease: relieving pain and preventing progression

INTRODUCTION

Paget's disease of bone (PDB) is a focal bone disorder caused by a marked dysregulation of osteoblasts and osteoclasts in basic multicellular units, leading to abnormal and disorganized deposition of collagen fibers (the so-called "woven bone"). Therefore, pagetic bones are increased in size, and at increased risk for bone pain, deformities, fractures, osteoarthritis, and, more rarely, neoplastic degeneration.

AREAS COVERED

In this review we revise the available information concerning the pharmacological treatment of PDB.

EXPERT OPINION

PDB progresses slowly within the affected skeletal sites and, if untreated, often leads to bone overgrowth, with bone pain, deformity and a likely increased risk of complications. Thus, the primary goal of treatment is the restoration of a normal bone turnover, in order to relieve bone pain or other symptoms and possibly prevent the complications. PDB long remained a poorly treatable disorder until the discovery of antiresorptive agents such as calcitonin first and bisphosphonates (BPs) later. With the recent development of potent intravenous BPs like zoledronate, allowing a better control of disease activity over the long term with a single infusion, has contributed to a marked improvement of the clinical management of this invalidating disorder.

Anti-inflammatory, but not osteoprotective, effect of the TRAF6/CD40 inhibitor 6877002 in rodent models of local and systemic osteolysis

NFκB plays a key role in inflammation and skeletal disorders. Previously, we reported that pharmacological inhibition of NFκB at the level of TRAF6 suppressed RANKL, CD40L and IL1β-induced osteoclastogenesis and attenuated cancer-induced bone disease. TNFα is also known to regulate TRAF6/NFκB signalling, however the anti-inflammatory and osteoprotective effects associated with inhibition of the TNFα/TRAF6/NFκB axis have not been investigated. Here, we show that in vitro and ex vivo exposure to the verified small-molecule inhibitor of TRAF6, 6877002 prevented TNFα-induced NFκB activation, osteoclastogenesis and calvarial osteolysis, but it had no effects on TNFα-induced apoptosis or growth inhibition in osteoblasts. Additionally, 6877002 disrupted T-cells support for osteoclast formation and synoviocyte motility, without affecting the viability of osteoblasts in the presence of T-cells derived factors. Using the collagen-induced arthritis model, we show that oral and intraperitoneal administration of 6877002 in mice reduced joint inflammation and arthritis score. Unexpectedly, no difference in trabecular and cortical bone parameters were detected between vehicle and 6877002 treated mice, indicating lack of osteoprotection by 6877002 in the arthritis model described. Using two independent rodent models of osteolysis, we confirmed that 6877002 had no effect on trabecular and cortical bone loss in both osteoporotic rats or RANKL- treated mice. In contrast, the classic anti-osteolytic alendronate offered complete osteoprotection in RANKL- treated mice. In conclusion, TRAF6 inhibitors may be of value in the management of the inflammatory component of bone disorders, but may not offer protection against local or systemic bone loss, unless combined with anti-resorptive therapy such as bisphosphonates.

Bisphosphonates in the management of Paget's disease

The first clinical use of bisphosphonates was in Paget's disease of bone (PDB) when disodium etidronate was found to be effective at suppressing metabolic activity of the disease. Subsequently, PDB became a testing ground for many bisphosphonates using changes in alkaline phosphatase (ALP) as the primary outcome measure in clinical trials. Bisphosphonates are now considered to be the treatment of choice for PDB since they are highly effective at suppressing the elevations in bone turnover that are characteristic of the disease. Short term studies have shown that treatment with alendronate and risedronate can promote formation of lamellar bone in affected sites and improve x-ray appearances in some patients. Bisphosphonates have also been shown to improve bone pain in PDB and within the bisphosphonates, zoledronic acid (ZA) is most likely to give a favourable pain response. Many patients with PDB do not have pain however, even when there is increased metabolic activity and more research is needed to find out why this is the case. The effects of bisphosphonates on complications of PDB such as deformity, pathological fractures and deafness have not been adequately studied since most clinical trials have been short term and have not collected information on these important outcomes. The PRISM and PRISM-EZ studies investigated the long-term effects of bisphosphonates in patients with established PDB using a treat-to-target approach and showed that intensive bisphosphonate therapy aimed at normalising ALP was no more effective than symptom directed treatment with bisphosphonates at preventing complications of PDB. The Zoledronate in the Prevention of Paget's Disease (ZiPP) trial, which is currently in progress, seeks to determine whether early intervention with this potent bisphosphonate might be effective in preventing disease progression. Should the ZiPP study yield positive results, genetic testing coupled to prophylactic bisphosphonate therapy might represent a new indication for these highly effective inhibitors of bone resorption in future years.

Bisphosphonates for Paget's disease of bone in adults

BACKGROUND

Bisphosphonates are considered to be the treatment of choice for people with Paget's disease of bone. However, the effects of bisphosphonates on patient-centred outcomes have not been extensively studied. There are insufficient data to determine whether reducing and maintaining biochemical markers of bone turnover to within the normal range improves quality of life and reduces the risk of complications.

OBJECTIVES

To assess the benefits and harms of bisphosphonates for adult patients with Paget's disease of bone.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, ISI Web of Knowledge and trials registers up to March 2017. We searched regulatory agency published information for rare adverse events.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of bisphosphonates as treatment for Paget's disease in adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened search results, extracted data and assessed studies for risk of bias. We used standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We included 20 trials (25 reports, 3168 participants). Of these, 10 trials (801 participants) compared bisphosphonates (etidronate, tiludronate, ibandronate, pamidronate, olpadronate, alendronate, risedronate, zoledronate) versus placebo, seven compared two bisphosphonates (992 participants), one trial compared a bisphosphonates with a bisphosphonate plus calcitonin (44 participants), and two studies, the largest trial (1331 participants) and its interventional extension study (502 participants), compared symptomatic treatment and intensive treatment where the goal was to normalise alkaline phosphatase.Most studies were assessed at low or unclear risk of bias. Six of 10 studies comparing bisphosphonates versus placebo were assessed at high risk of bias, mainly around incomplete outcome data and selective outcome reporting.Participant populations were reasonably homogeneous in terms of age (mean age 66 to 74 years) and sex (51% to 74% male). Most studies included participants who had elevated alkaline phosphatase levels whether or not bone pain was present. Mean follow-up was six months.Bisphosphonates versus placeboBisphosphonates tripled the proportion (31% versus 9%) of participants whose bone pain disappeared (RR 3.42, 95% confidence interval (CI) 1.31 to 8.90; 2 studies, 205 participants; NNT 5, 95% CI 1 to 31; moderate-quality evidence). This result is clinically important. Data were consistent when pain change was measured as any reduction (RR 1.97, 95% CI 1.29 to 3.01; 7 studies, 481 participants).There was uncertainty about differences in incident fractures: 1.4% fractures occurred in the bisphosphonates group and none in the placebo group (RR 0.89, 95% CI 0.18 to 4.31; 4 studies, 356 participants; very low-quality evidence).None of the studies reported data on orthopaedic surgery, quality of life or hearing thresholds.Results regarding adverse effects and treatment discontinuation were uncertain. There was a 64% risk of mild gastrointestinal adverse events in intervention group participants and 48% in the control group (RR 1.32, 95% CI 0.91 to 1.92; 6 studies, 376 participants; low-quality evidence). The likelihood of study participants discontinuing due to adverse effects was slightly higher in intervention group participants (4.4%) than the control group (4.1%) (RR 1.01, 95% CI 0.41 to 2.52; 6 studies, 517 participants; low-quality evidence). Zoledronate was associated with an increased risk of transient fever or fatigue (RR 2.57, 95% CI 1.21 to 5.44; 1 study, 176 participants; moderate-quality evidence).Bisphosphonates versus active comparatorMore participants reported pain relief with zoledronate than pamidronate (RR 1.30, 95% CI 1.10 to 1.53; 1 study, 89 participants; NNT 5, 95% CI 3 to 11) or risedronate (RR 1.36, 95% CI 1.06 to 1.74; 1 study, 347 participants; NNT 7, 95% CI 4 to 24; very low quality evidence). This result is clinically important.There was insufficient evidence to confirm or exclude differences in adverse effects of bisphosphonates (RR 1.05, 95% CI 0.95 to 1.76; 2 studies, 437 participants; low-quality evidence) and treatment discontinuation (2 studies, 437 participants) (RR 2.04, 95% CI 0.43 to 9.59; 2 studies, 437 participants; very low-quality evidence).Intensive versus symptomatic treatmentThere was no consistent evidence of difference to response in bone pain, bodily pain or quality of life in participants who received intensive versus symptomatic treatment.Inconclusive results were observed regarding fractures and orthopaedic procedures for intensive versus symptomatic treatment (intensive treatment for fracture: RR 1.84, 95% CI 0.76 to 4.44; absolute risk 8.1% versus 5.2%; orthopaedic procedures: RR 1.58, 95% CI 0.80 to 3.11; absolute risk 5.6% versus 3.0%; 1 study, 502 participants; low-quality evidence).There was insufficient evidence to confirm or exclude an important difference in adverse effects between intensive and symptomatic treatment (RR 1.05, 95% CI 0.79 to 1.41; low-quality evidence).There was insufficient evidence to confirm or exclude an important difference of risk of rare adverse events (including osteonecrosis of the jaw) from the regulatory agencies databases.

AUTHORS' CONCLUSIONS

We found moderate-quality evidence that bisphosphonates improved pain in people with Paget's disease of bone when compared with placebo. We are uncertain about the results of head-to-head studies investigating bisphosphonates. We found insufficient evidence of benefit in terms of pain or quality of life from intensive treatment. Information about adverse effects was limited, but serious side effects were rare, and rate of withdrawals due to side effects was low.

New therapeutic agents for the treatment of bone diseases

Bisphosphonates have demonstrated important clinical benefits for patients with malignant bone disease, metabolic bone diseases, such as Paget's disease, and postmenopausal osteoporosis. The introduction of nitrogen-containing bisphosphonates with high affinity for hydroxyapatite in bone represents an important advancement. These agents are now a standard of care for osteoporosis, Paget's disease, osteogenesis imperfecta, primary bone lesions from multiple myeloma and bone metastases from breast cancer. Moreover, the recent clinical development of zoledronic acid (4 mg by 15-minute intravenous infusion) has expanded the benefits of bisphosphonate therapy to patients with bone metastases from any solid tumour. Bisphosphonates are also being investigated at present for the prevention of bone loss resulting from cancer therapy. In addition, a variety of novel biologic agents, receptor activator of nuclear factor-kappaB (RANK) ligand antibodies, osteoprotegerin and cathepsin K inhibitors are being investigated at present for the treatment of malignant bone disease. The management of bone health is an important area of active research, and the armamentarium and role of bone-specific therapies continue to expand.

Periodontal host modulation with antiproteinase, anti-inflammatory, and bone-sparing agents. A systematic review

BACKGROUND

The use of modulating agents, including inhibition of matrix metalloproteinases (MMPs) with antiproteinases, blocking production of proinflammatory cytokines and prostaglandins with anti-inflammatory drugs, and inhibiting activation of osteoclasts with bone-sparing agents, has been postulated to be of therapeutic value as an adjunctive therapy to the management of chronic periodontitis.

RATIONALE

The objective of this systematic review of the literature was to assess the adjunctive efficacy of antiproteinase, anti-inflammatory, and bone-sparing host-modulating agents in the treatment of gingivitis, aggressive periodontitis, and chronic periodontitis. FOCUSED QUESTIONS: 1. In patients with periodontal diseases, what is the effect of host-modulation agents, alone or combined with conventional therapy, compared to conventional therapy alone as assessed by clinical, radiographic, adverse, and patient-centered outcomes? 2. In patients with dental implants, what is the effect of host-modulation agents on implant success assessed by clinical, radiographic, adverse, and patient-centered outcomes?

SEARCH PROTOCOL

MEDLINE, Embase, and the Cochrane Library databases were searched without language restrictions through April 1, 2002 for studies that used tetracycline (TET)-related matrix metalloproteinase (MMP) inhibitors, or non-steroidal anti-inflammatory drugs (NSAIDs) and bisphosphonate anti-osteolytic agents. The investigation also included hand searching of journals and contacting authors and industry experts.

SELECTION CRITERIA

INCLUSION CRITERIA

Only human studies (randomized controlled clinical trials, cohort studies, case-control studies, cross-sectional studies, and case series) were selected. Studies were on subjects with gingivitis, aggressive or chronic periodontitis, or dental implants. Interventions included TET-related MMP inhibitors, NSAIDs, or bisphosphonate anti-osteolytic agents.

EXCLUSION CRITERIA

Studies that used MMP tissue inhibitors as diagnostic or prognostic indicators of periodontal disease or that evaluated short-term systemic antibodies or locally delivered levels of drugs with antiproteinase activity were excluded.

DATA COLLECTION AND ANALYSIS

The primary outcomes for assessment were changes in bone or clinical attachment levels (CAL); secondary outcomes included clinical measures of plaque, gingival inflammation, probing depth (PD), and mobility. Summary data appropriate for meta-analysis were pooled using a weighted average and analyzed using a standardized difference; the results were checked with both fixed-effects and random-effects models.

MAIN RESULTS

1. A meta-analysis done on the studies reporting changes in CAL and PD following administration of sub-antimicrobial doses of doxycycline (SDD) in conjunction with scaling and root planing (SRP) in patients with periodontitis showed a statistically significant beneficial adjunctive effect. 2. There were insufficient data to provide meta-analyses on periodontal patients treated with other host-modulating agents; descriptive tables are included. 3. NSAIDS show promise in their ability to slow periodontal disease. 4. Preliminary data on bisphosphonate agents indicate there is a potential role for these agents in periodontitis management. 5. There are a very limited number of studies on host-modulating agents and dental implants and no analyses were possible. 6. Because the treatment methodologies and clinical variables differed considerably among the studies, it is difficult to summarize the information and identify a reliable total patient population.

REVIEWERS' CONCLUSIONS

1. Large multi-center trials are needed to evaluate the role of host-modulating agents in the treatment of periodontitis. 2. NSAIDS and bisphosphonate drugs may have a potential adjunctive role in periodontal therapy. 3. The adjunctive use of SDD with SRP is statistically more effective than SRP alone in reducing PD and in achieving CAL gain.

Prostate cancer and bone metastases: medical treatment

Prostate cancer is the most common malignancy in men in the United States. With the long natural history of the disease, management of skeletal morbidity related to advanced prostate cancer becomes a major public health issue. The standard of care in advanced prostate cancer is androgen deprivation therapy. This may accelerate the development of osteoporosis and further exacerbate the risks of having adverse skeletal-related events develop. Recently, the use of bisphosphonates in men who have not responded to androgen deprivation therapy has been shown to reduce the incidence of skeletal-related events with time. Questions remain as to whether bisphosphonates should be broadly applied to earlier stages of the disease or tailored to men at higher risk of having bone-related morbidity. Work is ongoing to improve other approaches to the medical treatment of bone metastases in patients with advanced prostate cancer including the use of radiopharmaceuticals and combined chemotherapy.

Dose-proportional pharmacokinetics of risedronate on single-dose oral administration to healthy volunteers

Risedronate is a pyridinyl bisphosphonate approved for the treatment of Paget's disease (US-FDA) and in development for the treatment and prevention of osteoporosis. This study examined risedronate pharmacokinetics and tolerability after oral administration using a randomized, double-blind, parallel-group design. Healthy male and female volunteers (n = 22-23 subjects per dose) received a single oral dose of 2.5, 5, or 30 mg risedronate. Serum and urine samples were collected for 72 and 672 hours, respectively, and risedronate concentrations were determined by ELISA. Safety was evaluated by monitoring adverse events, clinical laboratory measurements, vital signs, and electrocardiograms. Mean Cmax (0.41, 0.94, and 5.1 ng/mL for 2.5, 5, and 30 mg, respectively), AUC (1.8, 3.9, and 21 ng.h/mL for 2.5, 5, and 30 mg, respectively), and urinary excretion (22, 63, and 260 micrograms for 2.5, 5, and 30 mg, respectively) were dose proportional, and there were no significant differences in tmax or CLR among the three doses. All doses were well tolerated; no serious adverse events occurred, and all but one of the adverse events were mild or moderate in severity. There was no evidence of an acute phase reaction occurring after oral administration of risedronate.

Use of alendronate in peri-implant defect regeneration

BACKGROUND

Previous studies have demonstrated an increase in bone mass and density with use of systemic alendronate sodium. This agent acts as an inhibitor of osteoclast activity, and is thought to result in more net osteoblastic activity. The objective of this study was to determine the effects of locally applied alendronate sodium on guided bone regeneration around dental implants.

METHODS

Six adult mongrel dogs were divided into 2 groups: one group received alendronate-coated dental implants, and the other group served as control. Two types of dental implants were used in each dog: hydroxyapatite (HA)-coated and titanium machine-polished (TMP), for a total of 4 groups. Dental implants were placed immediately after extraction of the right and left second, third, and fourth mandibular premolars; a resorbable collagen membrane was secured over the implants and defects; and the flaps were closed primarily. Fluorescent labels were administered intravenously on days 0, 6, 12, and 22 to measure bone formation rate. Dogs were sacrificed on day 28. The specimens were sectioned and mounted, and bone formation rate was recorded with a computerized microscopic digitizer. Specimens were stained with Stevenel's blue and van Gieson's picric fuchsin. Bone-to-implant contact was recorded with a computerized microscopic digitizer.

RESULTS

The results indicated a significant effect of locally applied alendronate (P < 0.0001) with both types of implants (HA and TMP), as well as the HA coating (P< 0.02) on increased bone formation rate. Additionally, alendronate had a significant effect on bone-to-implant contact, with an increase in the TMP model (P < 0.0001) and a decrease in the HA model (P < 0.0001 ). HA coating also had a significant effect on increasing bone-to-implant contact (P < 0.04).

CONCLUSIONS

The results indicate that alendronate increases early bone formation rate around dental implants. Additionally, the local application as described resulted in greater bone-to-implant contact with TMP implants.

Effects of tiludronate and ibandronate on the secretion of proinflammatory cytokines and nitric oxide from macrophages in vitro

Bisphosphonates inhibit osteoclastic bone resorption and are used for the treatment of bone diseases. Some bisphosphonates, such as clodronate and tiludronate, can be incorporated into non-hydrolysable ATP analogues in cells, whereas the more potent anti-resorptive aminoalkylbisphosphonates are not metabolised. Furthermore, clodronate inhibits proinflammatory cytokine and nitric oxide (NO) secretion from activated macrophages in vitro and has anti-inflammatory properties in vivo, especially when delivered into cells by liposomes. By contrast, aminobisphosphonates can induce an acute phase response and fever in vivo, which appears to involve the induction of cytokine secretion. In this study we examined the effect of liposome-mediated intracellular delivery of one aminobisphosphonate, ibandronate, and one metabolizable bisphosphonate, tiludronate, on the secretion of inflammatory mediators. The intracellular uptake of bisphosphonates by macrophages was enhanced by a factor of 20-200 by using liposomes. Tiludronate dose-dependently inhibited both cytokine and NO secretion from activated macrophages, and liposomal tiludronate was more potent than the free drug. By contrast, ibandronate enhanced LPS-induced secretion of IL-1beta and IL-6 but did not affect TNFalpha or NO secretion at non-cytotoxic concentrations. The present results, together with our previous studies, strongly suggest that bisphosphonates can be grouped into those that are metabolised by cells and that are capable of inhibiting cytokine and NO secretion from macrophages, thus having potential anti-inflammatory properties, and those that are not metabolised but can actually enhance the production of cytokines following macrophage activation.

Effect of alendronate on cultured normal human osteoblasts

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

Alendronate in the treatment of Paget's disease of bone

We studied four treatment regimens of oral alendronate in 60 patients with active Paget's disease. Two groups received an oral daily dose of either 40 or 80 mg of alendronate for 3 months, followed by placebo for a further 3 months: the other two groups received treatment with 40 or 80 mg per day for 6 months. Activity of alkaline phosphatase and urinary hydroxyproline excretion were measured before, during, and after treatment, at intervals for a total follow-up of 1 year. A transiliac bone biopsy was performed in 24 patients before and after the treatment. An additional 16 patients had a third biopsy more than a year after stopping treatment. Alendronate induced a marked suppression in the urinary excretion of hydroxyproline within 2 weeks (p < 0.01) followed by a fall in serum activity of alkaline phosphatase at 1 month (p < 0.01) in all treatment groups. Nine months after the start of treatment patients treated with 80 mg for 6 months had a significantly lower mean alkaline phosphatase activity compared to the other treatment groups (p < 0.02), which persisted at 1 year (p < 0.05). Alkaline phosphatase decreased to within the laboratory reference range in all patients given 80 mg for 6 months. In contrast, alkaline phosphatase decreased to within the laboratory reference range in 73-83% of patients given 80 mg for 3 months and the 40 mg dose. Histomorphometric assessment showed a decrease in indices of bone turnover in the pagetic biopsies. None of the biopsies taken after treatment showed evidence of impaired mineralization of bone. Gastrointestinal side effects occurred in 25% of patients of whom two withdrew from treatment. We conclude that oral alendronate is an effective agent for the treatment of Paget's disease of bone.

Variable efficacy of bone remodeling biochemical markers in the management of patients with Paget's disease of bone treated with tiludronate

The aim of this work was to evaluate the response of different biochemical bone markers to tiludronate administration in Paget's disease of bone. Ten patients (five men and five women), 56-77 years old (67 +/- 6.5), were treated for 3 months with tiludronate tablets (400 mg/day). Bone formation markers: alkaline phosphatase (AP), bone alkaline phosphatase (bAP), osteocalcin (BGP), and procollagen I carboxyterminal propeptide (PICP) in serum; and bone resorption markers: serum cross-linked carboxyterminal telopeptides of type I collagen (ICTP), urinary hydroxyproline/creatinine (Hyp/Cr), pyridinoline/Cr (Pyr/Cr), and alpha-1 collagen chain products degradation (CrossLaps) were assessed. Samples were taken before and at monthly intervals for 3 months after treatment began. The results of the present work show that serum AP and bAP are sensitive and reliable biochemical markers of bone formation in the follow-up of tiludronate in this disease. Serum PICP shows less sensitivity than serum AP, and serum BGP is not indicated as biochemical marker in these types of studies. Urinary hydroxyproline seems to be the most reliable biochemical marker of bone resorption. More studies should be performed with urinary Pyr and CrossLaps determinations. Serum ICTP is not adequate for the follow-up of tiludronate treatment in Paget's disease of bone.

Intravenous administration of alendronate counteracts the in vivo effects of glucocorticoids on bone remodeling

The purpose of the investigation was to test the use of alendronate in the therapy of children affected by chronic rheumatic diseases and symptomatic drug-induced osteoporosis. Two courses of alendronate were intravenously administered to four girls with vertebral fractures that were glucocorticoid induced. Improvement of back pain and bone mineral density increase evaluated by DXA and conventional spine X-rays were observed. Our study supports the ABD-induced improvement of the negative effects of long-term therapy on bone mineral density in children with chronic rheumatic diseases.

Alendronate treatment for osteoporosis: a review of the clinical evidence

Bisphosphonates have recently gained an increasing role in the management of osteoporosis. The aminobisphosphonate, alendronate has recently been introduced as a new agent for the treatment of postmenopausal osteoporosis. This paper reviews the clinical evidence for the use of this agent and seeks to assess its place in osteoporosis management.

Sustained response to intravenous alendronate in postmenopausal osteoporosis

We studied the effects of alendronate (amino-hydroxybutylidene bisphosphonate) on biochemical indices of bone turnover and on lumbar spinal bone mineral density in 15 postmenopausal women with vertebral osteoporosis. Alendronate 7.5 mg daily was administered intravenously as a slow infusion for four consecutive days. Treatment was associated with a significant decrease in serum calcium (p < 0.01), fasting urinary calcium excretion (p < 0.01) and hydroxyproline excretion within several days followed a later decrease in serum alkaline phosphatase activity that showed a significant reduction at two months after treatment (p < 0.05). Serum calcium reverted to pretreatment values by the second week after infusion, but the decrease in alkaline phosphatase, urinary calcium, and hydroxyproline excretion persisted to six months after infusion. There was a 3% mean increase in lumbar bone mineral density at six months (p < 0.01). A transient lymphopenia or leucopenia was noted in eight patients and a short-lived fever in six. No other side effects were observed. This study demonstrates that shortterm exposure to high intravenous doses of alendronate induces suppression of bone resorption in osteoporosis that persists for at least 6 months after infusion. We conclude that a short exposure to high intravenous doses induces sustained effects on bone turnover in much the same manner as that observed in Paget's disease of bone.

Alendronate treatment of naturally-occurring periodontitis in beagle dogs

The treatment of periodontal disease has been largely directed at the microbiological etiology. The prevention of bone loss by modulating the host response to the bacteria may be a useful adjunctive method in the management of periodontitis. Alendronate, an amino bisphosphonate, may inhibit bone loss in osteolytic diseases by altering osteoclast activity. The objective of this double-blind study was to evaluate alendronate inhibition of alveolar bone loss in the naturally occurring beagle dog model of periodontitis. Sixteen 7 to 9 year old beagles with moderate-to-severe periodontitis were studied for 6 months. The dogs were stratified into two groups based on initial periodontal severity. One group received 3.0 mg/kg alendronate weekly orally and the other group received a placebo. Silk ligatures were placed on the study teeth for the first 3 months of the study to exacerbate the periodontal destruction. Clinical data were collected for attachment level, gingival index, plaque index, and mobility at baseline and one-month intervals. Intraoral radiographs were made at baseline and at 3 and 6 months. The mandibles were processed for histology at month 6. The radiographs were analyzed by digital image analysis of the subtracted images. A statistically significant difference in bone mass (P < 0.001) was observed between the alendronate and placebo groups. The bisphosphonate had no effect on the clinical parameters of gingival inflammation or plaque. A trend toward decreased attachment loss and mobility was observed in favor of the alendronate group.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of methods of assessing response of Paget's disease to bisphosphonate therapy

Bisphosphonates have been shown to be effective in suppressing the elevated bone turnover found in Paget's disease of bone. In theory, the major determinants of post-treatment bone turnover are the initial disease activity and the rate of decline in bone turnover with therapy. In the present study, we examined the rate of decrease of alkaline phosphatase and hydroxyproline (expressed as a half-life) and showed this to be superior to percentage changes in bone turnover as a marker of response. The combination of pre-treatment alkaline phosphatase and the alkaline phosphatase half-life and pre-treatment hydroxyproline and the hydroxyproline half-life were the best models to predict post-treatment bone turnover (multiple r = 0.75, r2 = 0.56, p < 0.0001; and r = 0.71, r2 = 0.51, p < 0.0001, respectively). In addition, measurement of the half-lives of these markers of bone turnover may allow prospective changes to be made during treatment so that maximal disease suppression can be achieved.

Rationale for the use of alendronate in osteoporosis

Bisphosphonates are being used in disorders associated with accelerated resorption of bone, particularly Paget's disease of bone and the bone disease of malignancy. Their undoubted biological efficacy and relatively low apparent toxicity make them attractive candidates for the management of osteoporosis. The bisphosphonate alendronate has many characteristics which suggest that it is suitable for use in osteoporosis. It is a potent inhibitor of osteoclast-mediated bone resorption with no adverse effect on the mineralization of bone. Earlier studies have shown it to be one of the most active bisphosphonates in Paget's disease and the hypercalcemia of malignancy. In common with other bisphosphonates tested thus far, alendronate appears to inhibit bone loss in a variety of experimental models of osteoporosis. Long-term studies are needed to determine its steady-state effects on bone mass in man. Most data indicate that alendronate is capable at least of decreasing the rate of bone loss, and might even induce increments in bone mass for many years. Since the experimental studies show that the increase in bone mass observed with alendronate is associated with an increase in bone strength, its use is likely to decrease the frequency of fractures. However, direct clinical evidence for this requires the outcome of well-designed long-term prospective studies.

Alendronate modulates osteogenesis of human osteoblastic cells in vitro

The bisphosphonates, which are carbon-substituted pyrophosphates, have been studied extensively both in vivo and in vitro to elucidate their effects on bone tissues and cells. However, because these agents were shown to have a potent inhibitory effect on bone resorption, the majority of studies have focused on only this aspect of bone metabolism. There appears to be less information regarding the direct effect of bisphosphonates on bone formation, so thus we undertook experiments to investigate the effects of bisphosphonates, especially alendronate, on the mineralization and matrix protein synthesis of human osteoblastic cells in vitro. The data show that the bisphosphonates, alendronate, etidronate and pamidronate, suppressed 1,25-dihydroxycholecalciferol (1,25(OH)2D3)-stimulated mineralization of human osteoblastic cells at high concentrations, while relatively lower concentrations of alendronate and etidronate potentiated mineralization of the cells in the presence of 1,25(OH)2D3. The potentiation of mineralization with alendronate was accompanied by increased synthesis of bone matrix proteins, osteocalcin and collagen, and the mRNA of pro alpha(I) collagen. These findings show that in addition to their well-known effects on bone resorption, bisphosphonates have significant and direct effects on osteogenesis in osteoblasts in vitro. The actual mechanism remains to be further investigated.

Duration of the effects of intravenous alendronate in postmenopausal women and in patients with primary hyperparathyroidism and Paget's disease of bone

The effect of a single intravenous (i.v.) infusion of 5 mg alendronate was studied in ten patients with Paget's disease, six patients with primary hyperparathyroidism and ten osteopenic postmenopausal women. Urinary hydroxyproline excretion significantly decreased within few days in all patients (from 113 +/- 67.9 to 58 +/- 35 mmol/mol Cr in Paget's disease, from 21.8 +/- 9 to 12.9 +/- 6 mmol/mol Cr in hyperparathyroidism, from 18.7 +/- 9.5 to 8.5 +/- 4.3 mmol/mol Cr in postmenopausal women). In the patients with Paget's disease urinary hydroxyproline remained suppressed over the 6 months of follow-up, whereas it rose toward pretreatment values within 4 and 6 weeks in the patients with primary hyperparathyroidism and in postmenopausal osteopenic women, respectively. Plasma alkaline phosphatase significantly fell only after 4-6 weeks in patients with primary hyperparathyroidism and in Pagetic patients. In the latter group alkaline phosphatase continued to decline thereafter and a plateau became apparent after 2 months. In postmenopausal women the serum alkaline phosphatase remained unchanged. Thus, the same dose of alendronate induces comparable fractional decreases of bone resorption in the three groups of patients, but the effect is persistent only in Paget's disease. This is consistent with the hypothesis that alendronate inhibits osteoclastic activity only at the level of the existing resorption sites. In osteoporotic and primary hyperparathyroid patients, as soon as the treatment is withdrawn, the appearance of new sites of resorption is not inhibited and bone turnover is resumed to pre-treatment values.(ABSTRACT TRUNCATED AT 250 WORDS)

Paget's disease of bone: five regimens of pamidronate treatment

The efficacy of five therapeutic regimens using (3-amino-1-hydroxypropylidene)-1,1- bisphosphonate (APD or pamidronate) was assessed in patients with Paget's disease of bone. These regimens were as follows: (a) pamidronate 600 mg/day given orally during six months; (b) iv infusion of 20 mg daily for 10 days; (c) iv infusion of 40 mg daily for 5 days; (d) iv infusion of 10 mg daily for 4 days and (e) a single iv infusion of 10 mg. Six months after the initiation of therapy, urinary excretion of hydroxyproline and serum alkaline phosphatase activity (expressed as percent of their initial value) were: Group a: 30 +/- 10 (mean +/- SE) and 30 +/- 6, Group b: 55 +/- 8 and 46 +/- 6, Group c: 54 +/- 7 and 57 +/- 6, Group d: 53 +/- 7 and 69 +/- 4, and Group e: 85 +/- 10 and 98 +/- 4 respectively. Oral route was accompanied by digestive intolerance. On the contrary, except for rare and transient "flu-like syndromes", the iv treatment was not associated with any serious secondary effect. Intravenous infusion of pamidronate, 20 mg for 10 days or 40 mg for 5 days, appears as an interesting alternative to the oral route in the treatment of Paget's disease of bone.

Histomorphometrical analysis of the effects of the bisphosphonate alendronate on bone loss caused by experimental periodontitis in monkeys

This study tested the efficacy of alendronate, a bisphosphate, in reducing alveolar bone loss caused by experimental periodontitis in cynomolgus monkeys. Periodontitis was initiated in adult monkeys by ligating mandibular molar teeth at the cementoenamel junction (CEJ) and subsequently inoculating the ligature with Porphyromonas (Bacteroides) gingivalis. Contralateral, homologous non-ligated teeth served as controls. Animals received, intravenously, either saline (placebo) or alendronate at 0.05 or 0.25 mg/kg every 2 weeks for 16 weeks. After the animals were sacrificed, coronal sections through mandibular molars were subjected to histomorphometrical analysis. No overt side-effects were observed in any of the animals participating in this study. In placebo-treated animals, ligation and inoculation resulted in significant bone loss both at the CEJ and at the furcation. Alendronate at 0.05 mg/kg significantly reduced bone loss associated with the experimental periodontitis at both sites. In contrast, the dose of 0.25 mg/kg was ineffective in attenuating alveolar bone loss in the furcation area and only slightly effective in preventing it at the CEJ area. The results of the histomorphometric analysis correlate closely with those of the radiographic analysis of the same experiment. These data indicate that alendronate could reduce the loss of alveolar support associated with periodontitis and suggest that bisphosphonates, by virtue of their significant inhibitory action on osteoclasts, may become a treatment modality in the battle against alveolar bone destruction during periodontal disease.

Biologic, histologic and densitometric effects of oral risedronate on bone in patients with multiple myeloma

Recent studies have shown that treatment with bisphosphonates could be effective against the myelomatous skeletal deterioration. However, the mechanisms of action of these drugs in multiple myeloma (MM) have been poorly studied. In the present study, 11 patients with MM and bone lesions were treated orally with 30 mg/day of risedronate for 6 months, and monitored for 6 additional months. Mean serum calcium decreased from day 4, with a concomitant increase in circulating levels of PTH (1-84) and 1,25-(OH)2D. These parameters reached their nadir on day 7 and returned to baseline value during the treatment period. Markers of bone resorption, pyridinoline and deoxypyridinoline decreased from day 7; they were at 50% and 78% of their basal value at the end of treatment and follow-up periods, respectively. A significant reduction of estimates of bone formation (serum alkaline phosphatase and osteoclacin) appeared at month 3 and persisted for the remainder of the 9-month period. Histomorphometric analysis showed a significant reduction of activation frequency, number of osteoclasts and erosion depth. Bone turnover was high at baseline, and normal after treatment, without mineralisation defects. Mean wall thickness was not different before and after treatment. Spinal bone mineral density measured by dual energy X-ray absorptiometry increased (5.3%) at the end of treatment. We conclude that oral risedronate in multiple myeloma induces a noticeable and rapid inhibition of bone resorption.

Determinants of remission of Paget's disease of bone

Bisphosphonates are a safe and effective treatment for Paget's disease of bone, but little information is available about the factors influencing the duration of remission so obtained. We assessed 60 patients with Paget's disease treated with disodium pamidronate (APD). The mean duration of remission was 9.5 months (range 3-25). The major influences were the initial pretreatment alkaline phosphatase (ALP; r = -4.6, p < 0.0001), minimum posttreatment ALP (r = -0.51, p < 0.0001), and the rate of response of bone turnover to the first dose of APD (r = 0.61, p < 0.0001). Multiple linear regression showed that the initial response to treatment was the most significant influence. Also, despite a minimum ALP within the normal range, the duration of remission varied considerably (4-25 months). This may be due to the difficulties in applying a population-based normal range to individuals.

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.

Parenteral pamidronate prevents thyroid hormone-induced bone loss in rats

Pamidronate (APD) is a bisphosphonate that prevents bone loss from a variety of causes. We studied the role of APD in preventing thyroid hormone-induced bone loss. A total of 32 rats were assigned to one of four treatment groups: (1) -APD/triiodothyronine (-T3), (2) -APD/+T3, (3) +APD/-T3, or (4) +APD/+T3. In the first of two studies, the rats received APD for the first week and T3 for the second week, and then their blood was analyzed for alkaline phosphatase and osteocalcin. Alkaline phosphatase and osteocalcin were significantly higher (p < 0.05) in hyperthyroid rats (-APD/+T3, 3.9 +/- 0.25 mukat/liter and 23 +/- 1.6 nM, respectively) than in control animals (2.53 +/- 0.28 mukat/liter and 18.3 +/- 1.4 nM, respectively). Hyperthyroid rats pretreated with APD (+APD/+T3) had levels of alkaline phosphatase and osteocalcin no different from controls. In a second study, rats were divided into the same four groups, except they received APD/placebo and T3/placebo concomitantly for 3 weeks. At the end of the study, bone mineral density (BMD) of the femur, spine, and whole body was measured by dual-energy x-ray absorptiometry, and the calcium content of the femora was measured directly. In hyperthyroid rats (-APD/+T3) BMD was significantly lower than in controls in the spine (0.201 +/- 0.004 versus 0.214 +/- 0.002 g/cm2, p < 0.05) and femur (0.204 +/- 0.003 versus 0.218 +/- 0.002, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Bisphosphonates in the treatment of metabolic bone diseases

Bisphosphonates (BP) are pyrophosphate analogs, P-C-P with various carbon side-chains. The phosphate groups are responsible for the low gastrointestinal absorption (about 1%), limited penetration into cells, adsorption to bone mineral and rapid excretion in the urine. Based on the C side-chains, BPs can inhibit osteoclastic bone resorption with potencies which differ by as much as 10,000-fold among compounds. The most potent inhibitors are aminobisphosphonates. Studies of the amino-BP alendronate show preferential uptake at sites of bone resorption where they block osteoclastic activity by inhibiting ruffled border formation. BPs are the treatment of choice for hypercalcaemia of malignancy, where a single infusion with a potent BP will normalize serum calcium in 80% of the patients. Paget's disease also shows an excellent long-term response to BPs. In addition, BPs are being studied for the treatment of osteoporosis and other bone disorders which could be helped by inhibition of bone resorption.

Clinical pharmacology of alendronate sodium

Clinical studies have been performed to investigate the pharmacokinetics and pharmacodynamics of alendronate, an inhibitor of bone resorption for the treatment of osteoporosis. Alendronate is one of the most potent bisphosphonates currently undergoing clinical investigation (> 100-fold more potent than etidronate in vivo). The pharmacokinetics of alendronate are similar to those of other bisphosphonates. After a 2-h intravenous infusion, plasma concentrations of alendronate decline rapidly to approximately 5% of initial values within 6 h. About 50% of a systemic dose is excreted unchanged in the urine in the 72 h following administration. By analogy to its behavior in animals the remainder is assumed to be taken up by the skeleton. After sequestration into bone, the elimination of alendronate is very prolonged. The terminal half-life was estimated to be greater than 10 years. Despite prolonged skeletal residence, the biological effects of alendronate begin to diminish post-treatment, since the duration of effect reflects factors besides dose and cumulative drug exposure. When taken after an overnight fast, 2 h before breakfast, the oral bioavailability of alendronate averages approximately 0.75% of dose with substantial variability (coefficient of variation 55%-75%) both between and within subjects. Reducing the wait before food from 2 h to 1 h, or even 30 min, produces a mean reduction in absorption of 40%. Since the clinical efficacy of alendronate is indistinguishable whether it is given 30 min, 1h, or 3 h before a meal, the observed variability in bioavailability within this range is of little consequence. Dosing up to at least 2 h after a meal dramatically reduces absorption (80%-90%).