MEN1-related hyperparathyroidism: response to cinacalcet and its relationship with the calcium-sensing receptor gene variant Arg990Gly.

Abstract

OBJECTIVE:

Primary hyperparathyroidism (PHPT) is a challenging problem in type 1 multiple endocrine neoplasia (MEN1) due to the high postsurgery recurrence rate. The aim was to evaluate the efficacy of cinacalcet in MEN1 patients in comparison with patients with sporadic PHPT (sPHPT) and the effect of Arg990Gly calcium-sensing receptor (CASR) polymorphism on the response to treatment.

DESIGN:

This is a randomized, crossover, double-blind study carried out in the University Hospitals.

METHODS:

Fifteen MEN1 patients with PHPT were randomized to two groups, one administered with 30 mg daily cinacalcet, titrated until calcium normalization, and one with placebo. After 3 months, patients were reassessed and after washout switched to the other treatment. For comparison, 20 sPHPT patients with similar calcium levels were administered with cinacalcet for 3 months. Ionized and total calcium, phosphate, and parathyroid hormone (PTH) were evaluated. CASR Arg990Gly was genotyped on blood DNA by direct sequencing.

RESULTS:

Cinacalcet normalized calcium, increased phosphate, and reduced PTH levels in all patients. Cinacalcet dosage required to normalize calcium in MEN1 and sPHPT was not significantly different (45±21 vs 54±25 mg/day). Few mild adverse events, not requiring drug withdrawal, were observed in both the groups. No association between Arg990Gly CASR polymorphism and response to cinacalcet was found.

CONCLUSIONS:

This short-term prospective study demonstrated that the efficacy profile of cinacalcet in patients with MEN1-related PHPT and in those with sPHPT was similar and was not influenced by the 990 CASR variant. Although long-term safety and efficacy data are required, cinacalcet might be considered a treatment option in MEN1 patients who have contraindications to surgery or persistent PHPT after surgery.

• Authors: Marcello Filopanti, Uberta Verga, Federica Ermetici, Luca Olgiati, Cristina Eller-Vainicher, Sabrina Corbetta, Luca Persani, Paolo Beck-Peccoz, Anna Spada
• Journal: European journal of endocrinology (Eur J Endocrinol) Vol. 167 Issue 2 Pg. 157-64 (Aug 2012) ISSN: 1479-683X [Electronic] England
• PMID: 22577108 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Calcimimetic Agents
• Naphthalenes
• Receptors, Calcium-Sensing
• Arginine
• Glycine
• Cinacalcet

Topics

• Adenoma (complications, diagnosis, drug therapy, genetics)
• Adult
• Amino Acid Substitution (genetics, physiology)
• Arginine (genetics)
• Calcimimetic Agents (therapeutic use)
• Cinacalcet
• Cross-Over Studies
• Double-Blind Method
• Female
• Glycine (genetics)
• Humans
• Hyperparathyroidism, Primary (diagnosis, drug therapy, etiology, genetics)
• Male
• Middle Aged
• Multiple Endocrine Neoplasia Type 1 (complications, diagnosis, drug therapy, genetics)
• Naphthalenes (therapeutic use)
• Parathyroid Neoplasms (complications, diagnosis, drug therapy, genetics)
• Polymorphism, Single Nucleotide (physiology)
• Prognosis
• Receptors, Calcium-Sensing (genetics)
• Treatment Outcome
• Young Adult