Treatment of tumor hypercalcemia with clodronate

Effective treatment of malignant hypercalcaemia with a single intravenous infusion of clodronate

Thirty patients with hypercalcaemia due to malignancy that persisted following rehydration, were treated with a single dose of the bisphosphonate, clodronate. Clodronate (1.5 g) was administered intravenously in 500 ml normal saline over 4 h. Serum and urine biochemistry were measured before and after treatment and the results were compared with data from 15 patients given the recommended regimen 300 mg intravenous clodronate daily for 5 consecutive days. The single infusion induced a rapid and significant fall in serum calcium, apparent at day 3 (P < 0.0001) that persisted to the end of follow-up at day 10 (P < 0.001). Eighty per cent (24/30) of patients became normocalcaemic. The response was associated with a significant decrease in fasting urinary calcium excretion, and no change in renal function, as judged by serum creatinine. The same dose of clodronate, given as 5 daily infusions, induced a comparable decrease in serum calcium, but was less rapid in onset so that at day 3 the serum calcium was significantly lower with the single infusion (P = 0.02). The calcium lowering effect of both regimens depended on the tumour type. We conclude that the single infusion of 1500 mg clodronate is as effective in reducing serum calcium as the same dose given over 5 days. The single infusion has a more rapid onset of effect, is more convenient than multiple infusions, and has no adverse effect on renal function.

Intravenous clodronate for the treatment of hypercalcaemia in breast cancer patients with bone metastases--a prospective randomised placebo-controlled multicentre study

In a double blind randomised multicentre study the effect of intravenous clodronate plus hydration was compared with placebo plus hydration in the treatment of hypercalcaemia in breast cancer patients with bone metastases. The patients were treated either with hydration plus clodronate 300 mg/day or hydration plus placebo, up to 7 days or until serum ionised calcium was below 1.4 mmol/l. 25 patients received clodronate and 19 placebo. A significant difference in favour of clodronate was observed in the time to reach normocalcaemia (P = 0.004) and in the number of patients achieving normocalcaemia (P = 0.0003). 17 patients of 21 evaluable patients on clodronate achieved normocalcaemia compared with 4 of 19 patients on placebo. The only adverse event clearly associated with clodronate was symptomatic hypocalcaemia in 1 patient. Thus, clodronate seems to be a safe and highly efficacious drug for the treatment of hypercalcaemia in breast cancer patients.

Treatment of hypercalcaemia of malignancy with clodronate

The bisphosphonate clodronate has been widely used in the treatment of hypercalcaemia and osteolytic bone metastases. It can normalize plasma calcium in most hypercalcaemic, rehydrated cancer patients when increased bone resorption is the prevailing disturbance of calcium metabolism. When given intravenously either as a single infusion or as repeated daily administrations, serum calcium levels fall to normal 3-5 days after the onset of therapy. Long-term maintenance treatment must be adjusted individually since relapse appears to depend upon the tumour type, the degree of malignancy and any anticancer therapy. In patients in whom increased tubular calcium reabsorption is the prevailing disturbance of calcium metabolism, the effect of clodronate on plasma calcium is incomplete, despite the normalization of bone resorption. This type of therapeutic response can be reproduced experimentally in bisphosphonate-treated animals receiving a constant infusion of parathyroid hormone-related peptide, a peptide isolated from various tumour types including lung, kidney, breast and neuroendocrine tumour of the pancreas. In patients having a good response to clodronate, the fall in plasma calcium is accompanied by an increase in the calcium-regulating hormones, parathyroid hormone and 1,25-dihydroxyvitamin D3. This homeostatic response probably explains why hypocalcaemia occurs rarely in clodronate-treated patients. No serious side-effects of treatment have been reported. Clodronate appears to be a safe and effective treatment for the hypercalcaemia of malignancy, where increased bone resorption is the major mechanism disturbing the homeostasis of extracellular calcium.

Clodronate in hypercalcemia of malignancy

Of the many compounds belonging to the diphosphonate family, clodronate has been widely used in hypercalcemia and osteolysis of malignancy. All published reports indicate that clodronate can normalize plasma calcium in the majority of hypercalcemic, rehydrated cancer patients in whom increased bone resorption is the prevailing disturbed calcium flux. In these patients, clodronate, given intravenously either as a single infusion or as repeated daily administrations, can normalize serum calcium, usually 3-5 days after the onset of therapy. In these good responders, long-term maintenance treatment should be individually adjusted since relapse appears to depend upon the type of tumor, the extent of malignancy and the administration of anticancer therapy. In a subset of well-rehydrated hypercalcemic patients in whom increased tubular calcium reabsorption represents the prevailing disturbed calcium flux, the acute effect of clodronate on plasma calcium is incomplete, despite the normalization of bone resorption. This type of therapeutic response can be experimentally reproduced in diphosphonate-treated animals receiving a constant infusion of parathyroid hormone-related peptide, a peptide isolated from lung, kidney and breast carcinomas. This indicates that, in addition to antiosteolytic drugs, such as clodronate, patients with hypercalcemia of malignancy would benefit from the development of agents that can selectively reduce the renal tubular reabsorption of calcium. In patients displaying a good response to clodronate, the fall in plasma calcium is accompanied by an increase in the calcium-regulating hormones, parathyroid hormone and 1,25-dihydroxyvitamin D3. This homeostatic reaction probably explains why hypocalcemia rarely occurs in clodronate-treated patients.(ABSTRACT TRUNCATED AT 250 WORDS)