Denosumab treatment for refractory hypercalcemia in a hemodialysis patient with tertiary hyperparathyroidism

The most appropriate surgical procedure for tertiary hyperparathyroidism is still controversial. Medical management may be considered in those patients with failed previous surgical intervention. There are limited medical options for tertiary hyperparathyroidism with renal dysfunction. The monoclonal antibody denosumab has been used in patients with osteoporosis and hypercalcemia of malignancy. We report a case of medically refractory hypercalcemia caused by tertiary hyperparathyroidism treated with denosumab. A 46-year-old female was on hemodialysis for 10 years. She was diagnosed with tertiary hyperparathyroidism due to hypercalcemia with a high level of intact parathyroid hormone (iPTH, 1411 pg/ml). After right parathyroidectomy 6 weeks, her serum calcium remained persistently elevated (Ca, 3.17 mmoL/L). Denosumab (60 mg) was administered subcutaneously, and her serum calcium quickly decreased (from 3.43 to 2.04 mmoL/L within 8 days) and was slightly elevated (Ca, 2.8 mmoL/L) 3 months later. We conclude that denosumab has a significant effect on the reduction of serum calcium for tertiary hyperparathyroidism patients. The long-term treatment effect and safety warrant more studies in the future.