Background: Cinacalcet (Sensipar) has been shown to decrease calcium levels in patients with primary hyperparathyroidism (PHPT); however, few other endpoints have been studied and long-term effects are not known.
Methods: At the discretion of a referring doctor, 70 patients began Cinacalcet as an alternative to surgery for PHPT. Patients were followed as long as the drug was tolerated at which time all underwent parathyroidectomy.
Results: Before treatment, serum calcium levels averaged 11.7 ± 0.5 (range, 11.0-15.1) and PTH averaged 156 ± 42 (range, 88-815); 93% had two or more classic parathyroid symptoms (average, 5.3; range, 0-9). Cinacalcet was discontinued in 19 patients (26%) within 4 months because of nausea/vomiting. The remainder (n = 51) were treated from 8 to 28 months. Calcium levels decreased in all patients but remained variable. PTH levels decreased in 80% of patients but always remained elevated. Only 3 (6%) had symptom relief (p = 0.8), whereas 11 (21.6%) felt worse (p < 0.05). Twenty-three patients took Cinacalcet for >1.5 years, 14 of which showed significant (>1 SD) decreases in bone density (p < 0.05), and none had increases in bone density. All had curative outpatient parathyroid surgery followed by partial or complete resolution of symptoms within 3 months in 88% (p < 0.001).
Conclusions: Cinacalcet reduces serum calcium but is not tolerated by many patients. Cinacalcet does not provide symptom relief of PHPT and more commonly increases subjective symptoms. Prolonged use is associated with continued bone loss in some patients, possibly due to persistent elevated PTH levels. With very few exceptions, pHPT can be cured via a quick outpatient operation, which remains the treatment of choice.