Treatment of Hypercalcemia in Parathyroid Cancer with WR-2721,5-2(3aminopropylamino) Ethyl-Phosphorothioic Acid

Publisher Website
Google Scholar
Abstract
The chemoprotective and hypocalcemic agent WR-2721, S-2-(3-aminopropylamino)ethyl-phosphorothioic acid, inhibits parathyroid hormone secretion in vivo and in vitro. The first clinical use of WR-2721 in refractory hypercalcemia secondary to parathyroid cancer is reported. After several days of saline diuresis the patient received WR-2721, 740 mg/m2 over 15 min, resulting in a fall in serum Ca from 11.76 to 9.06 mg/dl within 24 h. Serum parathyroid hormone levels decreased from 675 to 140 .mu.leq/ml 2 h after the infusion was complete. When hypercalcemia recurred the patient was retreated with differing doses and infusion rates to determine the optimal method of drug administration to provide a satisfactory hypocalcemic response without adverse effects. In this patient, WR-2721 in i.v. boluses of 150 mg/m2 was effective without adverse effects. Using high-pressure liquid chromatography with electrochemical detection, plasma pharmacokinetic studies showed that WR-2721''s distribution half-life is 0.55 min.