Zoledronate.

Zoledronate is the most potent and most long-acting bisphosphonate in clinical use, and is administered as an intravenous infusion. Its major uses are in osteoporosis, Paget's disease, and in myeloma and cancers to reduce adverse skeletal related events (SREs). In benign disease, it is a first- or second-line treatment for osteoporosis, achieving anti-fracture efficacy comparable to that of the RANKL blocker, denosumab, over 3 years, and it reduces fracture risk in osteopenic older women. It is the preferred treatment for Paget's disease, achieving higher rates of remissions which are much more prolonged than with any other agent. Some trials have suggested that it reduces mortality, cardiovascular disease and cancer, but these findings are not consistent across all studies. It is nephrotoxic, so should not be given to those with significant renal impairment, and, like other potent anti-resorptive agents, can cause hypocalcemia in patients with severe vitamin D deficiency, which should be corrected before administration. Its most common adverse effect is the acute phase response, seen in 30-40% of patients after their first dose, and much less commonly subsequently. Clinical trials in osteoporosis have not demonstrated increases in osteonecrosis of the jaw or in atypical femoral fractures. Observational databases are currently inadequate to determine whether these problems are increased in zoledronate users. Now available as a generic, zoledronate is a cost-effective agent for fracture prevention and for management of Paget's disease, but wider provision of infusion facilities is important to increase patient access. There is a need to further explore its potential for reducing cancer, cardiovascular disease and mortality, since these effects could be substantially more important than its skeletal actions.

Paget's disease of bone: an endocrine society clinical practice guideline.

OBJECTIVE: The aim of this guideline was to formulate practice guidelines for the diagnosis and treatment of Paget's disease of the bone. PARTICIPANTS: The guideline was developed by an Endocrine Society-appointed Task Force of experts, a methodologist, and a medical writer. EVIDENCE: This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence. CONSENSUS PROCESS: One group meeting, several conference calls, and e-mail communications enabled consensus. Committees and members of The Endocrine Society and the European Society of Endocrinology reviewed and commented on preliminary drafts of these guidelines. Two systematic reviews were conducted to summarize supporting evidence. CONCLUSIONS: We recommend that plain radiographs be obtained of the pertinent regions of the skeleton in patients with suspected Paget's disease. If the diagnosis is confirmed, we suggest that a radionucleotide bone scan be done to determine the extent of the disease. After diagnosis of Paget's disease, we recommend measurement of serum total alkaline phosphatase or, when warranted, a more specific marker of bone formation or bone resorption to assess the response to treatment or evolution of the disease in untreated patients. We suggest treatment with a bisphosphonate for most patients with active Paget's disease who are at risk for future complications. We suggest a single 5-mg dose of iv zoledronate as the treatment of choice in patients who have no contraindication. In patients with monostotic disease who have a normal serum total alkaline phosphatase, we suggest that a specific marker of bone formation and bone resorption be measured, although these may still be normal. Serial radionuclide bone scans may determine the response to treatment if the markers are normal. We suggest that bisphosphonate treatment may be effective in preventing or slowing the progress of hearing loss and osteoarthritis in joints adjacent to Paget's disease and may reverse paraplegia associated with spinal Paget's disease. We suggest treatment with a bisphosphonate before surgery on pagetic bone.

Odanacatib in the treatment of postmenopausal women with low bone mineral density: three-year continued therapy and resolution of effect.

The selective cathepsin K inhibitor odanacatib (ODN) progressively increased bone mineral density (BMD) and decreased bone-resorption markers during 2 years of treatment in postmenopausal women with low BMD. A 1-year extension study further assessed ODN efficacy and safety and the effects of discontinuing therapy. In the base study, postmenopausal women with BMD T-scores between -2.0 and -3.5 at the lumbar spine or femur received placebo or ODN 3, 10, 25, or 50 mg weekly. After 2 years, patients (n = 189) were rerandomized to ODN 50 mg weekly or placebo for an additional year. Endpoints included BMD at the lumbar spine (primary), total hip, and hip subregions; levels of bone turnover markers; and safety assessments. Continued treatment with 50 mg of ODN for 3 years produced significant increases from baseline and from year 2 in BMD at the spine (7.9% and 2.3%) and total hip (5.8% and 2.4%). Urine cross-linked N-telopeptide of type I collagen (NTx) remained suppressed at year 3 (-50.5%), but bone-specific alkaline phosphatase (BSAP) was relatively unchanged from baseline. Treatment discontinuation resulted in bone loss at all sites, but BMD remained at or above baseline. After ODN discontinuation at month 24, bone turnover markers increased transiently above baseline, but this increase largely resolved by month 36. There were similar overall adverse-event rates in both treatment groups. It is concluded that 3 years of ODN treatment resulted in progressive increases in BMD and was generally well tolerated. Bone-resorption markers remained suppressed, whereas bone-formation markers returned to near baseline. ODN effects were reversible: bone resorption increased transiently and BMD decreased following treatment discontinuation.

Biochemical assessment of Paget's disease of bone.

Biochemical measurements of bone turnover provide an objective assessment of disease activity and the response to treatment. Alkaline phosphatase is the best characterized of the bone turnover markers and reflects the extent and activity of Paget's disease. However, in addition to bone-specific alkaline phosphatase (Bone ALP), there is also osteocalcin (OC) and procollagen type 1 N-terminal propeptide (P1NP) as formation markers. A variety of telopeptides (C-terminal telopeptide of type I collagen, [CTX], N-telopeptide of type I collagen [NTX]) or cross-link breakdown products of type 1 collagen can be used to assess bone resorption. Total alkaline phosphatase (Total ALP), Bone ALP, and P1NP all perform similarly in diagnosis and in evaluating the response to treatment, but the general availability, low interassay variation, and inexpensiveness of Total ALP makes it the best test for routine use. Measurement of the biological variability of the different markers in stable, untreated Paget's disease indicates how great a change (critical difference) is needed to define a true alteration in disease activity. Bone ALP, P1NP, and NTX show the highest therapy induced change/critical difference ratio during antiresorptive treatment. Some of the resorption markers show more complex changes in response to treatment. Pyridinoline (PYD) or deoxypyridinoline (DPD) cross-links of type 1 collagen are excreted in urine either as free or as peptide bound moieties, but it is the latter which decrease by the greatest amount in response to bisphosphonate therapy. Newly formed type 1 collagen contains an aspartyl-glycine motif (alphaCTX), which undergoes spontaneous isoaspartyl formation to betaCTX as the bone ages. In untreated Paget's disease, the alphaCTX is raised proportionately more (16-fold) than betaCTX (3-fold) and decreases in response to bisphosphonate therapy to a greater extent than betaCTX (measured in the sCTX assay). As bisphosphonates have become more potent, the aim of treatment has shifted toward the achievement of a rate of bone turnover in the lower part of the reference range. This is important because the duration of remission of disease activity is strongly determined by the post treatment nadir bone turnover.

Oral antiresorptive therapy.

Oral antiresorptive agents play a pivotal role in the management of osteoporosis. This paper discusses the effects and potential future role of newer agents such as ibandronate. Alternative dosing schedules and routes of administration have become available and may improve fracture protection, compliance, and tolerability for the long term treatment of a chronic condition such as osteoporosis. Increasingly these agents are being used to reduce bone loss in other diseases associated with high risk for osteoporosis such as organ transplantation and cystic fibrosis. Such studies may act as prototypes for the extended use of this class of drugs in other chronic inflammatory disease states. The innovative, yet disappointing results from combining an antiresorptive agent (alendronate) with the anabolic effects of teriparatide is also discussed. The major problem that remains is the lack of direct comparison between the agents in terms of fracture endpoints.

Changes in bone density and turnover after alendronate or estrogen withdrawal.

OBJECTIVE: To compare bone mineral density (BMD) and bone turnover changes after therapy withdrawal in postmenopausal women treated with alendronate or estrogen-progestin. DESIGN: In this randomized, blinded, multinational, placebo-controlled trial, 1,609 healthy postmenopausal women ages 45 to 59 years were assigned to receive alendronate, placebo, or open-label estrogen-progestin (conjugated equine estrogens plus medroxyprogesterone acetate or a cyclic regimen of 17 beta-estradiol, norethisterone acetate and estradiol). Of the original women, one third after year 2 and one third after year 4 were switched from alendronate to placebo, while remaining blinded to treatment assignment. The women taking estrogen-progestin in years 1 to 4 were followed off therapy in years 5 and 6. BMD at the lumbar spine and hip and biochemical markers of bone turnover were measured. RESULTS: The treatment groups described in the current report represent 860 women at baseline; 481 women entered year 5, and 430 completed 6 years. BMD steadily decreased in the placebo group during all 6 years. In contrast, spine and hip BMD increased during the first 4 years in the groups receiving daily continuous alendronate 5 mg and estrogen-progestin. During years 5 and 6, BMD decreased at the lumbar spine -2.42% (95% CI = -4.10, -0.74) and total hip -1.09% (-2.60, 0.41) in the group previously treated with alendronate 5 mg for 4 years. In comparison, large BMD decreases were observed at the spine [-7.69% (-8.96, -6.41)] and total hip [-5.16% (-6.30, -4.01)] among women who had received estrogen-progestin for 4 years. CONCLUSION: Alendronate produces greater residual skeletal effects than estrogen-progestin after therapy discontinuation.

Oral antiresorptive therapy.

Oral antiresorptive agents play a pivotal role in the management of osteoporosis. This paper discusses the effects and potential future role of newer agents such as ibandronate. Alternative dosing schedules and routes of administration have become available and may improve fracture protection, compliance, and tolerability for the long term treatment of a chronic condition such as osteoporosis. Increasingly these agents are being used to reduce bone loss in other diseases associated with high risk for osteoporosis such as organ transplantation and cystic fibrosis. Such studies may act as prototypes for the extended use of this class of drugs in other chronic inflammatory disease states. The innovative, yet disappointing results from combining an antiresorptive agent (alendronate) with the anabolic effects of teriparatide is also discussed. The major problem that remains is the lack of direct comparison between the agents in terms of fracture endpoints.

A randomised, controlled comparison of different calcium and vitamin D supplementation regimens in elderly women after hip fracture: The Nottingham Neck of Femur (NONOF) Study.

BACKGROUND: survivors of hip fracture are at 5- to 10-fold risk of a second hip fracture. There is little consensus about secondary prevention. Many are given calcium and vitamin D, but the evidence supporting this is circumstantial. OBJECTIVE: to compare the effects of different calcium and vitamin D supplementation regimens on bone biochemical markers, bone mineral density and rate of falls in elderly women post-hip fracture. DESIGN: randomised controlled trial. SETTING: orthogeriatric rehabilitation ward. METHODS: 150 previously independent elderly women, recruited following surgery for hip fracture, were assigned to receive a single injection of 300,000 units of vitamin D(2), injected vitamin D(2) plus 1 g/day oral calcium, 800 units/day oral vitamin D(3) plus 1 g/day calcium, or no treatment. Follow-up was one year, with measurement of 25-hydroxyvitamin D, parathyroid hormone, bone mineral density, and falls. RESULTS: mean 25-hydroxyvitamin D increased and mean parathyroid hormone was suppressed in all the actively treated groups, more so in the group receiving combined oral vitamin D and calcium. Twenty per cent of participants injected with vitamin D were deficient in 25-hydroxyvitamin D a year later. Bone mineral density showed small but statistically significant differences of up to 4.6% between actively treated groups and placebo. Relative risk of falling in the groups supplemented with vitamin D was 0.48 (95% CI 0.26-0.90) compared with controls. CONCLUSION: Vitamin D supplementation, either orally or with injected vitamin D, suppresses parathyroid hormone, increases bone mineral density and reduces falls. Effects may be more marked with calcium co-supplementation. The 300,000 units of injected vitamin D may not last a whole year.

Comparison of intact and 'whole molecule' parathyroid hormone assays in patients with histologically confirmed post-renal transplant osteodystrophy.

BACKGROUND: Fragments of parathyroid hormone (PTH) have been identified (amino acids 7-84) which may interfere with commercially available 'intact molecule' PTH assays. Novel assays which employ an antibody directed to the first seven amino acids of the N-terminus of PTH are thought to be free from cross-reactivity with the 7-84 fragments, and therefore measure true 'whole molecule' PTH. Transplant recipients (as well as those in end-stage renal failure) have been reported to have elevated levels of 'intact' in comparison with 'whole molecule' PTH. METHODS: PTH concentrations were assessed in serum samples obtained from female renal transplant recipients previously classified as either having hyperparathyroid (n = 14) or adynamic bone disease (n = 14) by transiliac crest bone biopsy. PTH was measured as 'whole molecule' (Scantibodies 'whole molecule' PTH) and 'intact' (DPC Immulite 2000 intact PTH and Scantibodies total PTH). RESULTS: Scantibodies 'whole molecule' PTH (all-subject mean 48.7 ng/L, +/- 53.0) were significantly lower than DPC intact (83.5 ng/L, +/- 88.1; P < or = 0.0001) and Scantibodies total PTH (80.5 ng/L, +/- 92.4; P < or = 0.0001). However, the differences between the 'whole molecule' and 'intact' measurements were similar across the two patient groups, and reflected the lower reference range employed by the 'whole molecule' assay. CONCLUSION: The 'whole molecule' PTH assay was unable to discriminate between the two patient populations and provided very little additional clinical information to that obtained from the intact PTH assays.

Rescue of trophoblast apoptosis by parathyroid hormone-related protein.

The effects of the 1-34 N-terminal parathyroid hormone-related protein fragment (0-10 microM) and the 67-86 parathyroid hormone-related protein fragment (0-10 microM) on trophoblast apoptosis, induced by TNFalpha and IFN-gamma or by the protein kinase inhibitor staurosporine, were investigated. TNFalpha/IFN-gamma and staurosporine significantly increased the rate of apoptosis by fivefold and by eightfold, respectively. Parathyroid hormone-related protein (1-34) evoked a dose-dependent rescue of both TNFalpha/IFNgamma-induced and staurosporine-induced apoptosis, whereas parathyroid hormone-related protein (67-86) had no significant effect on staurosporine-induced apoptosis, and only significantly diminished TNFalpha/IFNgamma-induced apoptosis at 10 microM. Parathyroid hormone-related protein was thus found to be a cytotrophoblast apoptosis survival factor.