Treatment Of Cancer-related Hypercalcemia Research Articles

Intravenous Zoledronate 4 mg for the treatment of post-menopausal osteoporosis: A prospective open-labeled study

BackgroundZoledronate 5 mg intravenous (IV) annually is approved for treatment of post-menopausal osteoporosis. Zoledronate 4 mg which is approved for the treatment of cancer related hypercalcemia can be an alternative for Asian women who have smaller stature. ObjectivesTo examine the efficacy and safety of Zoledronate 4 mg IV annually for the treatment of post-menopausal osteoporosis. MethodA prospective open-labeled study was performed on 33 post-menopausal osteoporosis patients. All patients received a dose of IV Zoledronate 4 mg. Bone mineral density (DXA) was examined at baseline and 12 months after treatment. Beta-C-terminal telopeptide (β-CTX) and procollagen type-1-amino-terminal propeptide (P1NP) were obtained at baseline, 6, and 12 months after treatment. Adverse events were recorded. ResultsThe mean age (SD) was 69 (11.1) years old. The lumbar spine BMD increased significantly from the mean (SD) lumbar spine BMD at baseline of 0.833 (0.132) g/cm2 to 0.862 (0.132) after treatment (p = 0.001). There was no significant differences in total hip and femoral neck BMDs between baseline and 12 months after treatment. The β-CTX and P1NP decreased significantly from the mean (SD) of 0.44 (0.24) and 55.57 (38.6) ng/ml at baseline to 0.21 (0.11) and 27.26 (10.95) ng/ml after treatment (p < 0.001), respectively. Infusion reaction was observed in five patients. There were two fractures observed. ConclusionZoledronate 4 mg improved lumbar BMD and decreased β-CTX and P1NP significantly after 12 months of treatment. Zoledronate 4 mg could be an alternative to Zoledronate 5 mg for the treatment of post-menopausal osteoporosis.

Treatment of cancer-related hypercalcemia: the role of gallium nitrate.

Hypercalcemia is a common, life-threatening metabolic disorder that can be associated with cancer. Its pathophysiology includes enhanced osteoclastic bone resorption and decreased renal excretion of extracellular calcium. Symptoms of hypercalcemia include nausea, vomiting, bone pain, polyuria, renal insufficiency, bradycardia, and arrhythmia. The goals of medical therapy are to inhibit bone resorption and promote renal calcium excretion. Hydration is the first step in management. Treatments for hypercalcemia include phosphates, calcitonin, bisphosphonates, and gallium nitrate. Although intravenous phosphates prevent intestinal calcium absorption and inhibit mineral and bone matrix resorption, serious adverse events include renal failure, hypotension, extraskeletal calcification, and severe hypocalcemia. Calcitonin has a rapid onset of action and can lower serum calcium concentrations within hours, but its usefulness is limited by its short duration of effect and the development of tachyphylaxis. Bisphosphonates are effective inhibitors of bone resorption but appear to have decreased response rates in hypercalcemic patients with high levels of parathyroid-related protein. Gallium nitrate, an antitumor agent noncytotoxic to osteoclasts and bone cells, appears to be more effective than pamidronate, etidronate, and calcitonin in the treatment of cancer-related hypercalcemia. Importantly, unlike bisphosphonates, gallium nitrate is effective in both parathyroid-related protein-mediated and non-parathyroid-related protein-mediated hypercalcemia.

Gallium nitrate revisited.

Gallium nitrate, the nitrate salt of the "near-metal" element gallium, is highly effective in the treatment of cancer-related hypercalcemia. Unlike bisphosphonates, gallium nitrate is effective in both parathyroid hormone-related protein-mediated and non-parathyroid hormone-related protein-mediated hypercalcemia. Gallium nitrate's effects on bone are clearly different from those of bisphosphonates. Gallium nitrate enhances calcium and phosphate content of bone and has direct, noncytotoxic effects on osteoclasts at markedly lower doses than those used for the treatment of cancer-related hypercalcemia. The drug may have clinical application in a variety of disorders associated with accelerated bone loss, including multiple myeloma. Gallium nitrate was originally evaluated as an antitumor agent. Its antitumor activity occurs at somewhat higher doses than those used in the treatment of cancer-related hypercalcemia. Gallium nitrate has substantial single-agent activity in the treatment of advanced lymphoma, particularly diffuse large cell lymphoma, small lymphocytic lymphoma, and follicular lymphoma. Because of its profile, including a different mechanism of action and minimal myelosuppression, the drug merits further evaluation in the treatment of advanced lymphoma. Gallium nitrate also has activity in advanced bladder cancer and may be useful in patients with metastatic or unresectable disease failing first-line chemotherapy regimens. Gallium nitrate exhibits a range of dose-dependent pharmacologic actions that provide a basis for its therapeutic potential in a variety of diseases and warrants further investigational evaluation as an antiresorptive and antitumor agent.

In vivo Morphologic Changes in the Rat Osteoclast Induced by Gallium Nitrate: The Result of Toxicity or Other Effects?

Gallium nitrate, an approved antitumor drug, has found clinical application in the treatment of cancer-related hypercalcemia and of Paget’s disease; the exact mechanism of its action, however, remains unknown. The present study utilized rats in a 7-day exposure to gallium at doses similar to those used clinically. Quantitative histomorphometry and ultrastructural examination of osteoclast fine structure were carried out on specimens from animals with documented hypocalcemia. Gallium exposure produced striking changes in the osteoclast. The number of nuclei/osteoclast increased, and the ruffled borders of the osteoclasts were markedly decreased along the length of the Howship’s lacunar cavity. The absence of a decrease in osteoclast number and the types of changes seen in ultrastructure suggest that the mechanism of action of gallium seen here may differ from that of calcitonin, a nontoxic, reversible antiresorbing agent. Results underscore the difficulty in assessing the toxicity of agents such as gallium on the osteoclast, a mature differentiated cell which does not divide and which does not produce a characteristic extracellular matrix component.

Comparative study of pamidronate disodium and etidronate disodium in the treatment of cancer-related hypercalcemia.

This multicenter, double-blind, randomized trial was performed to determine the efficacy and safety of pamidronate disodium (APD) in comparison to etidronate disodium (EHDP) in the treatment of cancer-related hypercalcemia. Sixty-five male and female adult patients with cancer and corrected calcium levels of greater than or equal to 12.0 mg/dL after 24 hours of hydration were randomized to receive either 60 mg APD given as a single 24-hour infusion or 7.5 mg/kg EHDP given as a 2-hour infusion daily for 3 days. APD normalized corrected calcium levels in 70% (21 of 30) of patients, whereas EHDP did so in 41% (14 of 34) of patients (P = .026). The mean corrected serum calcium level decreased from 14.6 to 10.5 mg/dL in the APD-treated group and from 13.8 to 11.6 mg/dL in the EHDP-treated group within the first week of treatment. There was no difference in response to APD in patients without versus those with bone metastases (78% v 67%). Both drugs were well tolerated. This study demonstrated that a single 60-mg infusion of APD is safe and more effective than EHDP given at the dose of 7.5 mg/kg for 3 days in the treatment of cancer-related hypercalcemia.

Bone particles from gallium-treated rats are resistant to resorption in vivo

Gallium nitrate is a clinically effective agent for the treatment of cancer related hypercalcemia. The mechanism of action of this agent was investigated following development of a quantitative in vivo bone resorption assay modified from the method of Glowacki. In a preliminary study, the time course of resorption of 50 mg subcutaneous implants of bone powder in growing rats was followed by chemical analysis of mineral (ash and Ca) contents, enzymatic and histochemical assay of tartrate resistant acid phosphatase (TRAP) activity, and image analysis of changes in particle size using von Kossa stained sections. Day 21 was chosen as a single time point for the comparison of the extent of resorption of gallium-containing and control bone particles. Resorption of bone particles containing 0.39 μg Ga/mg bone was significantly inhibited relative to control particles. Mineral content (6.7 vs. 3.6 mg), Ca content (1.72 vs. 1.37 mg), and the percentage of the field covered by bone particles (12 vs. 9%) were greater in the animals which received gallium-containing bone particles. Similarly, the number of osteoclast-like cells and the TRAP activity in the gallium-containing bone particle implants at 21 days were increased relative to controls. These data indicate that gallium incorporation into bone matrix confers resistance to resorption.

Treatment of cancer-related hypercalcemia.

Hypercalcemia, a complication that develops in 10% to 20% of patients with cancer, results from disruption of the normal physiologic mechanisms that closely regulate calcium homeostasis. Most patients with hypercalcemia are seriously dehydrated, and this volume depletion further compromises the kidney's ability to excrete calcium. Replenishment of extracellular fluid, restoration of intravascular volume, and maintenance of saline diuresis are the cornerstones of initial therapy. In most patients, pharmacologic inhibition of abnormally increased osteoclastic resorption is necessary to normalize serum calcium and achieve long-term control. The severity of the hypercalcemia and the patient's renal function, bone marrow reserve, and anticipated response to specific antineoplastic agents can all influence the selection of an antihypercalcemic agent. Available drugs for initial therapy include calcitonin, plicamycin, and etidronate; several additional investigational agents have shown promising efficacy in controlling hypercalcemia of malignancy. The bisphosphonates have an excellent safety profile and appear to be the agents of choice for initial and long-term management of cancer-related hypercalcemia.