Cinacalcet in the management of primary hyperparathyroidism

Non-surgical management of primary hyperparathyroidism

The purpose of this chapter is to discuss the options available for patients with primary hyperparathyrodism (PHPT) not undergoing parathyroidectomy (PTx). Adequate hydration should be recommended in all patients. Calcium intake should not be restricted and vitamin D deficiency should be corrected aiming at a serum concentration of 25OHD of >20 ng/mL or even higher (>30 ng/mL according to some opinion leaders). Pharmacologic therapy is not an alternative to PTx and could be considered in patients who meet the surgical criteria but unwilling to undergo PTx, as well as in patients with an increased risk of surgery or failed surgery. Targeted therapy includes antiresorptive drugs for skeletal protection and cinacalcet for lowering serum calcium. Combined therapy can be an option when appropriate. Pregnant women should be treated conservatively (hydration) and surgery, if needed, performed in the second trimester of pregnancy. Severe hypercalcemia is a life-threatening condition and requires immediate intensive treatment.

Identification of potent, nonabsorbable agonists of the calcium-sensing receptor for GI-specific administration

Modulation of gastrointestinal nutrient sensing pathways provides a promising a new approach for the treatment of metabolic diseases including diabetes and obesity. The calcium-sensing receptor has been identified as a key receptor involved in mineral and amino acid nutrient sensing and thus is an attractive target for modulation in the intestine. Herein we describe the optimization of gastrointestinally restricted calcium-sensing receptor agonists starting from a 3-aminopyrrolidine-containing template leading to the identification of GI-restricted agonist 19 (GSK3004774).

Cinacalcet in the management of primary hyperparathyroidism: post marketing experience of an Italian multicentre group

OBJECTIVE

To report the Italian experience on cinacalcet use following its approval by the European Medical Agency (EMA) to control hypercalcaemia in patients with primary hyperparathyroidism (PHPT).

DESIGN

Retrospective data collection from 100 patients with sporadic (sPHPT) and 35 with familial PHPT (fPHPT) followed in eight Italian centres between October 2008 and March 2011.

MEASUREMENTS

Albumin-adjusted serum calcium, PTH, 25OHD, daily cinacalcet dose and adverse events were recorded during the follow-up (1-46 months).

RESULTS

Baseline serum calcium was 2·90 ± 0·27 nmol/l in sPHPT and 2·75 ± 0·17 nmol/l in fPHPT patients (P = 0·007). The cinacalcet EMA labelling was met in 53% sPHPT and 26% fPHPT patients. High surgical risk (34%), negative preoperative imaging (19%), control of hypercalcaemia before parathyroidectomy (PTx) (24%), and refusal of PTx (19%) accounted for cinacalcet prescription in 96% of sPHPT patients. Conversely, initial treatment (34%), persistent/relapsing PHPT after surgery (31%), and refusal of PTx (14%) were the indications in 79% fPHPT patients. Cinacalcet was started at 30 mg/daily in 64% of sPHPT and 91% of fPHPT and increased until normocalcaemia was reached or side effects occurred. The final daily dose ranged between 15 and 120 mg. The majority of patients (65% of sPHPT and 80% of fPHPT) become normocalcaemic. Treatment was withdrawn in six patients because of side effects.

CONCLUSIONS

There is a wide heterogeneity in the prescription of cinacalcet in PHPT patients in Italy and the EMA labelling is not always followed, particularly in fPHPT patients. Cinacalcet effectively reduces serum calcium in patients with either sPHPT or fPHPT.