Treatment of malignancy-associated hypercalcemia with intravenous aminohydroxypropylidene diphosphonate

Treatment of malignancy-associated hypercalcemia remains unsatisfactory. We have prospectively treated 26 consecutive hypercalcemic cancer patients with intravenous (IV) aminohydroxypropylidene diphosphonate (APD). The drug was administered daily as a 15-mg two-hour IV infusion until both serum and urinary calcium had been normalized for 48 hours. Twenty-four patients were fully evaluable (eight head and neck tumors, seven breast cancers, three epidermoid tumors of the lung, and six miscellaneous neoplasms). Whereas rehydration had only inconsistent effects, APD normalized serum calcium in all patients after a mean of three daily doses: serum calcium decreased from 13.3 +/- 0.4 mg/dL (mean +/- SEM) before APD to 8.0 +/- 0.1 mg/dL at the end of treatment. Ionized calcium declined in parallel to total calcium. APD was as effective in hypercalcemia due to bone metastases as in paraneoplastic hypercalcemia. The drug was tolerated without toxicity and had a prolonged effect: serum calcium remained normal during 3+ weeks (1 + to 8 +) in 17 patients who did not receive or did not respond to antitumoral treatment. APD normalized serum calcium by inhibiting bone resorption, as evidenced by the dramatic decrease in urinary excretion of calcium and hydroxyproline. Inhibition of bone resorption was probably also responsible for the decrease in serum phosphorus from 2.9 +/- 0.2 to 2.0 +/- 0.1 mg/dL. In summary, IV APD constitutes a major advance in the treatment of malignancy-associated hypercalcemia: it is very effective, well tolerated, and has a prolonged efficacy.