Endocrine Abstracts

Refractory or severe hypercalcemia is important clinical problem as it can lead to serious complications such as arrhythmias, acute or chronic pancreatitis, gastric ulcer, water and electrolyte balance disturbances, osteoporosis, psychoses and even to hypercalcemic crisis. Most often it is diagnosed in parathyroid cancer (PC). It is also observed in benign primary hyperparathyroidism (HPTH) in case of difficulties with adenoma’s localization. Routinely treatment includes forced diuresis and/or bisphosphonates. Calcimimetics are a new group of drugs which increase the sensitivity of the calcium sensing receptor (CaR) to extracellular calcium and due to that reduce serum calcium and PTH level.

Aim: The aim of the study was to assess the efficacy of cinacalcet in the treatment of refractory hypercalcemia due to primary hyperparathyroidism.

Material and methods: Seven patients (6 women and 1 man, mean age 49 years) have been treated with cinacalcet for 3–117 weeks (median 31 weeks). In 1 patient PC, whereas in 6 of them benign HPTH were stated. Two of them were operated before cinacalcet therapy, In 3 patients the treatment was carried out to prepare them for surgery. Applied doses of cinacalcet ranges from 30 to 180 mg. In all patients forced diuresis and/or bisphosphonates were given before and during treatment.

Results: All patients responded to cinacalcet therapy. Serum total and Ca++ levels decreased significantly (P<0.05) whereas serum PTH level did not differ before and during the treatment. Only in one calcemia was normalized. Mean serum PTH, total and Ca++ before therapy were 744 pg/ml, 2.75 mmol/l, 1.47 mmol/l and during the treatment respectively 780 pg/ml, 2.55 mmol/l, 1.37 mmol/l. Usually the medication was well-tolerated. Most common adverse events were nausea and vomiting, especially at the beginning of therapy.

Conclusion: Cinacalcet is an effective, safe and well-tolerated treatment of patients with severe or refractory hypercalcemia due to primary hyperparathyroidism.