Gene/Protein Disease Symptom Drug Enzyme Compound
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 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The prolonged administration of bisphosphonates can reduce the frequency of morbid skeletal events in patients with metastatic breast carcinoma or multiple myeloma. The development of more potent bisphosphonates will simplify current therapeutic schemes and could improve the therapeutic effectiveness of bisphosphonate therapy. Zoledronate (CGP-42446) is the most potent of the clinically tested compounds. It is a cyclic third-generation bisphosphonate that is 100-850 times more active than pamidronate in several in vivo and in vitro pharmacological test systems. The first therapeutic trial with zoledronate has been performed in patients with tumor-induced hypercalcemia (corrected calcium [Ca] > 2.75 mmol/L after rehydration). In a Phase I multicenter trial, it was shown that a single infusion was already effective at dose levels of 0.02 and 0.04 mg of zoledronate/kg bodyweight, thus 1.2 and 2.4 mg total dose for an average 60-kg individual. Five of 5 patients became normocalcemic after a dose of 0.02 mg/kg, and 14 of 15 (93%) after a dose of 0.04 mg/kg. The median time to normalization of serum Ca was 2 days and the median duration of action was 33 days, suggesting that zoledronate has a faster onset and a longer duration of action than other clinically tested bisphosphonates. Zoledronate was well tolerated; the only side effect was an increase in body temperature in 30% of the cases, which was probably not drug-related in many patients. A Phase I trial also has been initiated in patients with lytic bone metastases. Zoledronate was given as monthly short infusions (5-30 minutes) at doses between 0.1-8.0 mg. There was an analgesic effect and even at low doses (2 mg and above), the effects on the biochemical markers of bone resorption appeared to be greater than after 90-mg pamidronate infusions. These initial human data suggest that zoledronate can be administered as convenient short intravenous infusions and lead to a more marked and a more prolonged inhibition of bone resorption than is currently possible with available compounds. Future trials will have to determine whether prolonged treatment with this extremely potent bisphosphonate also can have a greater effect on the morbidity of bone metastases.
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PMID:Clinical research update: zoledronate. 936 40

In a double blind randomized study, the bisphosphonate drug Pamidronate (Aredia) significantly protected Durie-Salmon stage III multiple myeloma patients from osteolytic bone disease. In the patient sub-group on salvage chemotherapy. Pamidronate treatment was also significantly associated with prolonged survival. To test if this drug could induce direct antitumor effects, we exposed myeloma cells to increasing concentrations of Pamidronate or a more potent bisphosphonate, Zoledronate. A concentration- and time-dependent cytotoxic effect was detected on four of five myeloma cell lines as well as three specimens obtained directly from myeloma patients. Zoledronate-induced cytotoxicity was significantly greater than that of Pamidronate. Cytotoxicity could not be explained by bisphosphonate-induced chelation of extracellular calcium or secondary decrease in production of the myeloma growth factor interleukin-6. Morphological examination, DNA electrophoresis and cell cycle analysis indicated that the bisphosphonate-induced cytotoxic effect consisted of a combination of cytostasis and apoptotic myeloma cell death. Enforced expression of BCL-2 protected against the apoptotic death but not against cytostasis. Most cytotoxic effects were seen between 10 and 100 microM of drug. The results suggest a possible direct anti-tumor effect in myeloma patients treated with bisphosphonates which may participate in their significantly increased survival. This hypothesis should now be further tested in clinical trials.
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PMID:In vitro cytoreductive effects on multiple myeloma cells induced by bisphosphonates. 951 85

Zoledronate is a new heterocyclic imidazole bisphosphonate that is the most potent bisphosphonate administered in humans because it is 100-850 times more potent than pamidronate, according to in vitro or animal models of bone resorption. We conducted an open-label, dose-finding, single-dose phase I study in tumor-induced hypercalcemia (TIH), which has been similarly used as a model to determine the active doses of other bisphosphonates. The primary objective was to determine, with a dose escalation schedule, two nontoxic dose levels of zoledronate able to induce normocalcemia in at least 80% of patients with TIH after rehydration (corrected Ca for albumin levels >/=2.75 mmol/l). Based on estimates of potency, the starting dose was 0.002 mg/kg, and further tested doses were 0. 005, 0.01, 0.02, and 0.04 mg/kg. To obtain a more precise estimate of the response rate, we treated 10 more patients at the highest of the two effective dose levels. The median infusion time of zoledronate was 30 minutes. Thirty out of the 33 treated patients were evaluable for efficacy. Thirty percent of the patients had breast cancer and 54% had metastatic bone involvement. For all groups combined, mean Ca levels at baseline was 3.0 mmol/l. The two effective dose levels were 0.02 mg/kg and 0.04 mg/kg. Five out of five patients became normocalcemic after 0.02 mg of zoledronate/kg and 14 out of 15 after 0.04 mg of zoledronate/kg. The success rate of the latter dose was thus 93% (95% confidence interval [CI] 68-100%). At this dose, the first day of normocalcemia was day 2 or 3 for all but one patient. The duration of normocalcemia for the two effective doses could be assessed in nine patients; seven patients remained normocalcemic throughout the trial (32-39 days). The fall in serum Ca was accompanied by a marked fall in fasting urinary Ca excretion. Zoledronate was well tolerated: 7 out of 33 patients developed transient hypophosphatemia, and 3 developed transient hypocalcemia. The only clinically detectable side effect was an increase in body temperature occurring in 10 (30%) patients. In summary, very low doses of zoledronate (0.02 mg/kg and 0.04 mg/kg, i. e., 1.2 mg and 2.4 mg for a 60-kg individual, respectively) administered by a short-time infusion effectively treated patients with TIH. The fall in serum Ca was rapid, and normocalcemia was often maintained for several weeks. Zoledronate was well tolerated. Future trials will determine whether prolonged treatment with this potent compound can have greater effects on the skeletal morbidity rate in patients with tumor bone disease than can be achieved with currently available bisphosphonates.
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PMID:A dose-finding study of zoledronate in hypercalcemic cancer patients. 1046 84

Metastatic bone disease develops as a result of the many interactions between tumour cells and bone cells. This leads to disruption of normal bone metabolism, with the increased osteoclast activity seen in most, if not all, tumor types providing a rational target for treatment. The clinical course of metastatic bone disease in multiple myeloma, breast and prostate cancers is relatively long, with patients experiencing sequential skeletal complications over a period of several years. These include bone pain, fractures, hypercalcaemia, and spinal cord compression, all of which may profoundly impair a patient's quality of life. External beam radiotherapy and systemic endocrine and cytotoxic treatments are the mainstay of treatment in advanced cancers. However, it is now clear that the bisphosphonates provide an additional treatment strategy, which reduces both the symptoms and complications of bone involvement. Pamidronate (Aredia(TM)) is the most widely evaluated bisphosphonate and is recommended for most patients with multiple myeloma or breast cancer with bone metastases. Current research aims include the evaluation of new potent bisphosphonates such as zoledronic acid (Zometa(TM)). It is hoped that this compound is not only more convenient and easier to administer but also more effective in inhibiting skeletal morbidity. Zometa may also have some direct anticancer activity. Preclinical studies with Zometa have demonstrated its potential in malignant bone disease. Clinical studies in treatment of hypercalcemia of malignancy have been completed, as have Phase I and II trials in patients with cancer and pre-existing bone metastases. Three randomized, double-blind, controlled Phase III trials are now ongoing to establish the efficacy and safety of Zometa in treatment of bone metastases in patients with osteolytic and osteoblastic lesions. Additionally, new specific molecules such as osteoprotogerin have been developed that are based on our improved understanding of the cellular signalling mechanisms involved in cancer induced bone disease. These potent molecules are now entering clinical trials. Ongoing research is aimed at trying to define the optimum route, dose, schedule and type of bisphosphonate in metastatic bone disease and their use in the prevention and treatment of osteoporosis in cancer patients. In vitro suggestions of direct anti-cancer activity and some promising clinical data in early breast cancer have resulted in considerable interest in the possible adjuvant use of bisphosphonates to inhibit the development of bone metastases.
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PMID:Optimising treatment of bone metastases by Aredia(TM) and Zometa(TM). 1111 66

Preclinical studies with zoledronic acid (Zometa; Novartis Pharmaceuticals Corp, East Hanover, NJ) have shown its potential in malignant bone disease. Clinical studies in the treatment of hypercalcemia of malignancy have been completed, as have phase I and II trials in patients with cancer and pre-existing bone metastases. Three randomized, double-blind, controlled phase III trials are ongoing to establish the efficacy and safety of zoledronic acid in the treatment of osteolytic and osteoblastic bone metastases. In one study, 4 mg zoledronic acid is compared with the standard therapy, 90 mg pamidronate, in treatment of osteolytic lesions in patients with breast cancer and multiple myeloma. Two other studies, one in patients with prostate cancer and bone metastases and another in patients with non-small cell lung cancer and other tumor types, are placebo-controlled. The primary end point in all three studies is the frequency of skeletal complications resulting from bone metastases. Adjuvant trials that assess the ability of zoledronic acid to prevent or reduce the incidence of bone metastases in patients at high risk for future skeletal metastasis are also planned or ongoing. The rationale and design of these ongoing and planned studies is discussed.
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PMID:The role of zoledronic acid in cancer: clinical studies in the treatment and prevention of bone metastases. 1134 60

The propensity for breast cancer cells to metastasize to bone and to induce osteolysis has long been recognized. Characteristics of both the tumor cells and the bone microenvironment contribute to this phenomenon. The presence of tumor in bone is associated with activation of osteoclasts, resulting in excessive bone resorption and subsequent osteolysis. Breast cancer cells and other tumor types influence osteoclastic bone resorption by increasing the number of osteoclasts and enhancing their resorptive activity. Parathyroid hormone-related peptide, in addition to its role in humorally mediated hypercalcemia, is secreted by metastatic breast cancer cells in bone in which it acts as a paracrine factor to stimulate osteoclasts. As bone matrix is broken down by activated osteoclasts, a rich supply of mitogenic factors is released, including insulin-like growth factors, bone morphogenetic proteins, and fibroblast growth factors. Transforming growth factor (TGF)-beta, one of the most abundant of the bone-derived factors, promotes increased production of parathyroid hormone-related peptide by tumor cells, establishing a "vicious cycle" leading to progressive tumor growth and bone destruction. Bisphosphonates interrupt this cycle by inhibiting osteoclasts, in part by inducing osteoclast apoptosis. In several animal models of breast cancer metastasis to bone, bisphosphonates decrease the number of new bone metastases and inhibit progression of existing lesions. A single 3 microg intravenous injection of zoledronic acid (Zometa; Novartis Pharmaceuticals Corp, East Hanover, NJ), a new highly potent bisphosphonate, prevented destruction of trabecular bone in an orthotopic mouse mammary tumor model. Tumor volume in bone was decreased by zoledronic acid in a dose-dependent manner in the same model, and tumor cell apoptosis was increased by zoledronic acid in bone metastases in the 4T1 murine model of mammary carcinoma metastasis. Zoledronic acid at a dose of 1.0 microg/d for 10 days also reduced bone lesion area in a nude mouse model with existing bone metastases. Although bisphosphonates, including zoledronic acid, are able to induce apoptosis in tumor cells in vitro, studies in animal models to date have generally not shown a reduction in nonosseous tumor. Therefore, bisphosphonate-associated tumor reduction in bone is most likely mediated by osteoclast inhibition or is related to high local concentrations of bisphosphonates in the bone compartment.
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PMID:Preclinical studies with zoledronic acid and other bisphosphonates: impact on the bone microenvironment. 1134 63

Potential antitumor effects of bisphosphonates are discussed, and trial results of zoledronic acid, a bisphosphonate that recently received FDA approval for the treatment of hypercalcemia of malignancy (HCM), are described. Substitution at two sites on the central carbon in the phosphate-carbon-phosphate backbone has resulted in bisphosphonates increasingly more potent than the first such drug, etidronate disodium. Besides having an antihypercalcemic effect, the nitrogen-containing bisphosphonates pamidronate disodium and zoledronic acid have been shown to have an antitumor effect. Possible mechanisms include inducing apoptosis in tumor cells, inhibiting angiogenesis, and reducing adherence of cancer cells to the bone matrix. Zoledronic acid 4 mg is superior to pamidronate disodium 90 mg in achieving a normal serum calcium concentration, without increased toxicity. Zoledronic acid has a higher response rate, faster onset, and longer duration of action, and is more convenient to administer. Doses of > or = 1.5 mg given every four weeks for three months resulted in sustained reductions in urinary markers of bone resorption. Clinical trial results suggest that zoledronic acid 4 mg is at least as effective as pamidronate disodium 90 mg in preventing skeletal complications of osteolytic disease. Zoledronic acid is superior to pamidronate disodium in treating HCM and more convenient to administer. More research to evaluate its safety and effectiveness at higher doses is needed before its full antitumor potential is realized.
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PMID:Advances in the biology and treatment of myeloma bone disease. 1175 4

Tumour-induced hypercalcaemia (TIH) is the most common metabolic disorder associated with cancer, and if left untreated is associated with a low survival rate. Bisphosphonates are potent inhibitors of bone resorption. They have emerged as the standard method of treatment for TIH and a new form of medical therapy for bone metastases in addition to current treatments. Newer forms of bisphosphonates are 100-1000 times more potent than pamidronate, the current gold standard. One of these third generation bisphosphonates, zoledronic acid (Zometa, Novartis Pharmaceuticals) has already been shown to provide more effective treatment of TIH than pamidronate. Ongoing research is aimed at choosing the optimum route, type of bisphosphonate and combination therapy to inhibit the development of bone metastases and TIH.
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PMID:Metastatic bone disease and tumour-induced hypercalcaemia: the role of bisphosphonates. 1206 26

Bisphosphonates (BPs) are potent inhibitors of osteoclast-mediated bone resorption, and it is well accepted that tumor cells in bone, especially breast cancer and myeloma cells, can stimulate osteoclast formation and activity leading to the release of growth factors or cytokines, which will further stimulate cancer cells' growth and their secretion of osteolytic factors. BPs are now the standard treatment for cancer hypercalcemia, for which a dose of 90 mg of pamidronate or 1500 mg of clodronate is recommended; the former compound is more potent and has a longer lasting effect. Repeated pamidronate infusions exert clinically relevant analgesic effects in more than half of patients with metastatic bone pain. Recent data suggest that non-responding patients should perhaps be treated with higher doses. The optimal dose actually remains to be defined, especially as it is thought that it is probably a function of the disease stage. Regular pamidronate infusions can also achieve a partial objective response according to conventional UICC criteria and they can almost double the objective response rate to chemotherapy. Lifelong administration of oral clodronate to patients with breast cancer metastatic to bone reduces the frequency of morbid skeletal events by more than one-fourth. Two double-blind randomized placebo-controlled trials comparing monthly 90 mg pamidronate infusions to placebo infusions for 1-2 years in addition to hormone or chemotherapy in patients with at least one lytic bone metastasis have shown that the mean skeletal morbidity rate could be reduced by 30-40%. The results obtained with intravenous BPs are generally viewed as better than those obtained with oral clodronate. However, preference can be given to the oral route when BPs are started early in the process of metastatic bone disease in a patient receiving hormone therapy. According to the recently published ASCO guidelines, pamidronate 90 mg i.v. delivered over 2 h every 3-4 weeks can be recommended in patients with metastatic breast cancer who have imaging evidence of lytic destruction of bone and who are concurrently receiving systemic therapy with hormonal therapy or chemotherapy. Furthermore, the ASCO Panel considered it "reasonable" to start i.v. BPs in women with localized pain whose bone scans were abnormal and plain radiographs normal, but not when an abnormal bone scan is asymptomatic. The pertinence of these criteria is discussed below. Because BPs are providing supportive care, reducing the rate of skeletal morbidity but evidently not abolishing it, the criteria for stopping their administration have to be different from those used for classic antineoplastic drugs, and they should not be stopped when metastatic bone disease is progressing. However, criteria to determine whether and for how long an individual patient benefits from their administration are lacking. New biochemical markers of bone resorption might help identify those patients continuing to benefit from therapy. Even better results have been achieved in patients with multiple myeloma, and the general consensus is that BPs should be started as soon as the diagnosis of lytic disease is made in myeloma patients. On the other hand, data are scanty in prostate cancer, but large-scale trials with potent BPs are ongoing or planned in such patients. Similar results to those achieved with pamidronate have been obtained with monthly 6-mg infusions of the newer BP ibandronate in patients with breast cancer metastatic to bone. The tolerance of ibandronate could be better, and the drug has the potential to be administered as a 15- to 30-min infusion. Zoledronate can also be administered safely as a 15-min 4-mg infusion, and large scale phase III trials have just been completed. These newer BPs will simplify the current therapeutic schemes and improve the cost-effectiveness ratio; they also have the potential to improve the therapeutic efficacy, at least in patients with an aggressive osteolytic disease or when given as adjuvant therapy. For that matter, initial data with clodronate indicate that they have the potential to prevent the development of bone metastases, but the use of BPs in the adjuvant setting must still be viewed as experimental.
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PMID:Bisphosphonates for cancer patients: why, how, and when? 1213 23

Bisphosphonates (BPs) are pyrophosphate analogues in which the oxygen in P-O-P has been replaced by a carbon, resulting in a metabolically stable P-C-P structure. Pamidronate (1b, Novartis), a second-generation BP, was the starting point for extensive SAR studies. Small changes of the structure of pamidronate lead to marked improvements of the inhibition of osteoclastic resorption potency. Alendronate (1c, MSD), with an extra methylene group in the N-alkyl chain, and olpadronate (1h, Gador), the N,N-dimethyl analogue, are about 10 times more potent than pamidronate. Extending one of the N-methyl groups of olpadronate to a pentyl substituent leads to ibandronate (1k, Roche, Boehringer-Mannheim), which is the most potent close analogue of pamidronate. Even slightly better antiresorptive potency is achieved with derivatives having a phenyl group linked via a short aliphatic tether of three to four atoms to nitrogen, the second substituent being preferentially a methyl group (e.g., 4g, 4j, 5d, or 5r). The most potent BPs are found in the series containing a heteroaromatic moiety (with at least one nitrogen atom), which is linked via a single methylene group to the geminal bisphosphonate unit. Zoledronic acid (6i), the most potent derivative, has an ED(50) of 0.07 mg/kg in the TPTX in vivo assay after sc administration. It not only shows by far the highest therapeutic ratio when comparing resorption inhibition with undesired inhibition of bone mineralization but also exhibits superior renal tolerability. Zoledronic acid (6i) has thus been selected for clinical development under the registered trade name Zometa. The results of the clinical trials indicate that low doses are both efficacious and safe for the treatment of tumor-induced hypercalcemia, Paget's disease of bone, osteolytic metastases, and postmenopausal osteoporosis.
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PMID:Highly potent geminal bisphosphonates. From pamidronate disodium (Aredia) to zoledronic acid (Zometa). 1216 45


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