Endocrine Abstracts

Background: The treatment of choice for primary hyperparathyroidism (PHPT) is surgical parathyroidectomy. Cinacalcet is the first calcimimetic approved by European Medicines Agency (EMA) in 2008 for use in patients with PHPT who are not fit for surgery or refuse surgery. British National Formulary (BNF) recommends it for hypercalcaemia in PHPT where parathyroidectomy is inappropriate. The main aim of treatment with cinacalcet is to keep calcium levels at safe levels.

Objectives: To evaluate the efficacy and safety of cinacalcet in patients with PHPT who were unfit for surgery, refused surgery or remain hypercalcaemic post-parathyroidectomy and not amenable to further intervention (complex PHPT).

Methods: We assessed the demographic and clinical characteristics and biochemistry in 12 patients seen in endocrinology and biochemistry clinics with complex PHPT at the commencement of cinacalcet and after approximately 1, 3, 6 and 12 months. We also checked doses, tolerability and side effects of cinacalcet.

Results: Most patients (66.67%) needed small maintenance dose of cinacalcet once a day. Mean baseline adjusted calcium level was 3.36 mmol/l (13.44 mg/dl) with a range of 2.91–5.36 mmol/l (11.64–21.44 mg/dl). There was a significant reduction in adjusted calcium levels at approximately 1 month (10.08%), 3 months (11.93%), 6 months (13.57%) and 12 months (20.17%). Calcium normalised in most patients (83.33%), and one patient developed hypocalcaemia necessitating cinacalcet dose reduction. All patients adhered to the treatment with two people experiencing self-limiting nausea and vomiting.

Conclusion: Our patient cohort indicates that cinacalcet is an effective and safe alternative to surgery in patients with complex PHPT. Cost-effectiveness analyses are needed to allow more widespread use in such patients. Further studies with long-term follow-up are required to assess efficacy in preventing osteoporosis and renal complications related to PHPT.