Endocrine Abstracts

Introduction: In type 1 multiple endocrine neoplasia (MEN1), primary hyperparathyroidism (PHPT) is a challenging problem due to the high post-surgery recurrence rate. Cinacalcet is a calcimimetic agent which showed to be effective in patients in whom surgery is contraindicated or refused. In this study we assessed the efficacy and the safeness of cinacalcet in MEN1 patients, in comparison with patients with sporadic PHPT (sPHPT). Moreover, the influence of Arg990Gly CASR polymorphism was also evaluated.

Design and methods: A randomised, cross-over, double-blind study was set up in University Hospitals context. Fifteen patients with PHPT MEN1-associated were randomised in two groups, one treated with 30 mg daily cinacalcet, titrated until calcium normalization, and one with placebo. Patients were reassessed after 3 months and switched to the other treatment once washed out. Twenty patients with cinacalcet treated sPHPT, having similar calcium levels, were considered as comparison group. Calcium/phosphate metabolism, bone turnover markers, liver and kidney functions, and perceived quality of life were evaluated at each assessment step. Arg990Gly CASR polymorphism was genotyped on leukocyte DNA by direct sequencing.

Results: Cinacalcet was able to normalize calcium levels and to reduced PTH in all patients, without significant effects on bone metabolism markers and quality of life. Cinacalcet dosage in MEN1 was not significantly different to sPHPT patients (45±21 vs 54±25 mg/day). Few mild adverse events were observed in both groups, not requiring drug withdrawal. No association between Arg990Gly CASR polymorphism and response to cinalcalcet was found.

Conclusions: Although this is a short-term prospective study, it demonstrated that efficacy and safety profile of cinacalcet was similar both in patients with MEN1-associated PHPT and in those with sporadic PHPT, with no 990Gly CASR variant influence. Thus, in MEN1 patients, cinacalcet treatment might be considered an effective and safe option.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.