Objective: Evaluate cinacalcet use and effect based on follow-up within a cohort study of recently diagnosed Primary Hyperparathyroidism (PHPT) patients. Characteristics, treatment indications and biochemical data are presented with measures of cinacalcet efficacy and safety.
Methods: The Swiss Primary Hyperparathyroidism Cohort Study is a prospective, non-interventional project to collect clinical, biochemical and outcome data in patients with PHPT initiated in June 07. It is multicentric, including 253 patients in 15 centres in Switzerland. Patients started on cinacalcet were identified and the indication for treatment recorded. We compared pre and post treatment calcium and parathyroid hormone levels (PTH).
Results: From June 2007 to December 2010, 30 patients were treated with the cinacalcet. Indications for treatment were: 3 patient refusals of parathyroidectomy (PTX), 14 preoperative (4 symptomatic), 4 recurrences /persistences post-PTX, 3 symptomatic hypercalcemia patients, 1 case where surgery was contraindicated, 4 to decrease serum calcium levels and 1 missing. Cinacalcet patients were younger than cohort population (mean age±SD: 63.2±16.1 vs 69.5±14.1 years). Median (± IQR) pre-treatment calcium was significantly higher at 2.83±0.36 mmol/l amongst cinacalcet recipients versus 2.66±0.27 mmol/l (P=0.02). PTH levels tended to be higher at 16.6±9.3 vs 11.7±7.8 pmol/l. The median cinacalcet start dose was 30±30 mg/day, thereafter adapted to 30 to 420 mg. Median post-treatment calcium decreased significantly to 2.72±0.5 mmol/l (P=0.0005). PTH levels decreased insignificantly to 14.3±4.7 mmol/l. Forty-five and ten percent of patients had normalised serum calcium and PTH levels, respectively. Adverse effects were observed in 3 subjects: hypocalcemia, muscle cramps and nausea.
Conclusion: Treatment with cinacalcet is an effective and safe way of reducing calcium levels pending surgery or when surgery is contraindicated.