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Potent Bisphosphonate (potent + bisphosphonate)
Selected AbstractsPharmacologic profile of zoledronic acid: A highly potent inhibitor of bone resorptionDRUG DEVELOPMENT RESEARCH, Issue 4 2002Jonathan R. Green Abstract Bisphosphonates are effective in treating benign and malignant skeletal diseases characterized by enhanced osteoclastic bone resorption (i.e., osteoporosis, Paget's disease, tumor-induced osteolysis). The nitrogen-containing bisphosphonate pamidronate is currently the standard treatment for hypercalcemia of malignancy (HCM) and skeletal complications of bone metastases. Zoledronic acid, a novel nitrogen-containing bisphosphonate with an imidazole substituent, has demonstrated more potent inhibition of osteoclast-mediated bone resorption than all other bisphosphonates, including pamidronate, in both in vitro and in vivo preclinical models. Zoledronic acid inhibited ovariectomy-induced bone loss in adult monkeys and rats, and long-term treatment prevented skeletal turnover and subsequent bone loss, reduced cortical porosity, and increased mechanical strength. Zoledronic acid also significantly inhibited bone loss associated with arthritis, bone metastases, and prosthesis loosening. The increased potency of zoledronic acid vs. pamidronate has been demonstrated clinically: zoledronic acid (4 or 8 mg iv) was superior to pamidronate (90 mg iv) in normalizing corrected serum calcium in patients with HCM. In patients with bone metastases, low doses of zoledronic acid (, 2 mg) suppressed bone resorption markers , 50% below baseline, whereas pamidronate 90 mg yielded only 20 to 30% suppression. Importantly, the increased potency of zoledronic acid is not associated with an increased incidence of local (bone) or systemic adverse events. Zoledronic acid does not impair bone mineralization and, compared with pamidronate, has a greater renal and intestinal tolerability therapeutic index. Thus, based on preclinical assays and clinical data, zoledronic acid is the most potent bisphosphonate tested to date. Given its potency and excellent safety profile, zoledronic acid is now poised to become the new standard of treatment for HCM and metastatic bone disease. Drug Dev. Res. 55:210,224, 2002. © 2002 Wiley-Liss, Inc. [source] Monthly Oral Ibandronate Therapy in Postmenopausal Osteoporosis: 1-Year Results From the MOBILE StudyJOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2005Paul D Miller MD Abstract Once-monthly (50/50, 100, and 150 mg) and daily (2.5 mg; 3-year vertebral fracture risk reduction: 52%) oral ibandronate regimens were compared in 1609 women with postmenopausal osteoporosis. At least equivalent efficacy and similar safety and tolerability were shown after 1 year. Introduction: Suboptimal adherence to daily and weekly oral bisphosphonates can potentially compromise therapeutic outcomes in postmenopausal osteoporosis. Although yet to be prospectively shown in osteoporosis, evidence from randomized clinical trials in several other chronic conditions shows that reducing dosing frequency enhances therapeutic adherence. Ibandronate is a new and potent bisphosphonate with antifracture efficacy proven for daily administration and also intermittent administration with a dose-free interval of >2 months. This report presents comparative data on the efficacy and safety of monthly and daily oral ibandronate regimens. Materials and Methods: MOBILE is a 2-year, randomized, double-blind, phase III, noninferiority trial. A total of 1609 women with postmenopausal osteoporosis were assigned to one of four oral ibandronate regimens: 2.5 mg daily, 50 mg/50 mg monthly (single doses, consecutive days), 100 mg monthly, or 150 mg monthly. Results: After 1 year, lumbar spine BMD increased by 3.9%, 4.3%, 4.1%, and 4.9% in the 2.5, 50 /50, 100, and 150 mg arms, respectively. All monthly regimens were proven noninferior, and the 150 mg regimen superior, to the daily regimen. All monthly regimens produced similar hip BMD gains, which were larger than those with the daily regimen. All regimens similarly decreased serum levels of C-telopeptide, a biochemical marker of bone resorption. Compared with the daily regimen, a significantly larger proportion of women receiving the 100 and 150 mg monthly regimens achieved predefined threshold levels for percent change from baseline in lumbar spine (6%) or total hip BMD (3%). All regimens were similarly well tolerated. Conclusions: Monthly ibandronate is at least as effective and well tolerated as the currently approved daily ibandronate regimen in postmenopausal osteoporosis. [source] Inhibition of osteoblast function in vitro by aminobisphosphonatesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2009Isabel R. Orriss Abstract Bisphosphonates are analogues of pyrophosphate, a key physicochemical inhibitor of mineralisation. We examined the direct actions of bisphosphonates on the function of cultured osteoblasts derived from rat calvariae. Treatment with zoledronate, the most potent bisphosphonate studied, reduced osteoblast number at concentrations ,100 nM and was strongly toxic at 10 µM, causing a threefold decrease in osteoblast viability after 2 days and a 90% decrease in cell numbers after 14 days. In control osteoblast cultures on plastic, abundant formation of ,trabecular' mineralised bone matrix nodules began after 10 days. Continuous exposure to zoledronate inhibited bone mineralisation at concentrations as low as 10 nM. Pamidronate and clodronate exerted similar effects but at higher doses (,1 and ,10 µM, respectively). Short-term or intermittent exposure of osteoblasts to zoledronate and pamidronate (1,10 µM) was sufficient to inhibit bone mineralisation by ,85%. Zoledronate but not pamidronate or clodronate also strongly inhibited osteoblast alkaline phosphatase activity at concentrations ,100 nM and soluble collagen production at concentrations ,1 µM. We additionally studied the effects of zoledronate on osteoblasts cultured on dentine, a bone-like mineralised substrate, observing similar inhibitory effects, although at concentrations 10,100-fold higher; this shift presumably reflected adsorption of zoledronate to dentine mineral. Thus, zoledronate blocked bone formation in two ways: first, a relatively non-toxic, selective inhibition of mineralisation at concentrations in the low nanomolar range and second, a cytotoxic inhibition of osteoblast growth and function at concentrations ,1 µM. Although no data are available on the bisphosphonate concentrations that osteoblasts could be exposed to in vivo, our results are consistent with earlier observations that bisphosphonates may inhibit bone formation. J. Cell. Biochem. 106: 109,118, 2009. © 2008 Wiley-Liss, Inc. [source] Multiple myeloma biology: lessons from the 5TMM modelsIMMUNOLOGICAL REVIEWS, Issue 1 2003Karin Vanderkerken Summary:, Multiple myeloma (MM) is a B cell neoplasm characterized by the monoclonal proliferation of plasma cells in the bone marrow, the development of osteolytic lesions and the induction of angiogenesis. These different processes require three-dimensional interactions, with both humoral and cellular contacts. The 5TMM models are suitable models to study these interactions. These murine models originate from spontaneously developed myeloma in elderly mice, which are propagated by in vivo transfer of the myeloma cells into young syngeneic mice. In this review we report on studies performed in the 5TMM models with special emphasis on the homing of the myeloma cells, the characterization of the migrating and proliferating clone and the identification of the isotype switch variants. The bone marrow microenvironment was further targeted with osteoprotegerin (OPG) to block the RANK/RANKL/OPG system and with potent bisphosphonates. Both treatments resulted in a significant protection against myeloma-associated bone disease, and they decreased myeloma disease, as evidenced by a lower tumor load and an increased survival of the mice. These different studies demonstrate the strength of these models, not only in unraveling basic biological processes but also in the testing of potentially new therapeutic targets. [source] Preventing osteoporotic fractures with antiresorptive therapy: implications of microarchitectural changesJOURNAL OF INTERNAL MEDICINE, Issue 1 2004S. Boonen Abstract. Prospective studies have demonstrated that low bone mass correlates well with increased risk of osteoporotic fractures at various skeletal sites. Trials have likewise confirmed that enhancing bone mass with antiresorptive therapy reduces fracture incidence in individuals at risk. However, correlation of bone mineral density (BMD) increases with therapeutic risk reduction has proved less consistent than correlation of BMD decreases with greater fracture risk in the untreated. Indeed, various analyses have indicated that , even during treatment with potent bisphosphonates like alendronate and risedronate , BMD changes from baseline account for <30% of the reduction in vertebral fractures in treated women. It is clearly, therefore, that factors other than BMD are involved in the reduction of fracture risk achieved by antiresorptive therapies. According to recent micro-computed tomography imaging and other studies, antiresorptive therapy can help rebuild the microarchitecture of bone as well as strengthen the materials that go into it. When treating individuals with osteoporosis, these microarchitectural changes contribute to the reduction of fracture risk achieved by antiresorptive therapies. [source] | ||||||||||