Endocrine Abstracts

JOINT3675

Background: The first line treatment for primary hyperparathyroidism (pHPT) is parathyroidectomy, however, some patients are unfit for or do not accept surgery. In such cases, cinacalcet (a calcimimetic) can be initiated with the aim to normalise blood calcium levels and mitigate direct effects associated with hypercalcaemia. For patients who are not suitable for parathyroidectomy, the UK’s national guidelines suggest use of cinacalcet if hypercalcaemia-related symptoms are present and serum aCa is 2.85-3.00mol/l or if aCa is >3.00mmol/l, irrespective of symptoms.

Aims: To assess local practice against NICE guidance [NG132] for prescribing cinacalcet in patients with primary hyperparathyroidism. To evaluate treatment effect on adjusted calcium levels and investigate treatment duration required to achieve normocalcaemia, including any intolerances and reasons for discontinuing cinacalcet.

Method: A retrospective study of all patients initiated on cinacalcet from June 2011 to February 2024 at Queen Elizabeth Hospital, Birmingham. This includes collection of biochemical data, inpatient and outpatient records and prescribing data.

Results: Of the 61 patients started on cinacalcet, 40 were commenced following the release of the national guidance in May 2019. 37 of these 40 patients (92.5%) were prescribed cinacalcet according to the NICE guidance. Most outpatients had accompanying prescribing checklist forms (21/27) since local introduction. A significant reduction in serum aCa was seen in patients after cinacalcet treatment (mean 2.56, 95%CI 2.49-2.63 mmol/l) when compared to baseline figures (mean 3.06, 95%CI 3.00-3.11 mmol/l). Additionally, 45 patients (73.8%) achieved normocalcaemia after a median duration of 30 days and 120 days each for inpatients and outpatients respectively. 16/61 patients reported side effects, and of these, 3 patients stopped their medication (nausea, vomiting, worsened dyspepsia).

Conclusion: Local prescribing generally adhered to national NICE guidance. The specialist team initiation and input, as well as thorough prescribing checklists when starting the medication in outpatient endocrine clinics, greatly contributed to this. Although a small number of patients were started on cinacalcet outside the guidance, reasons for doing so included symptom control in those unfit for surgery, persistent hypercalcaemia following surgery and bridging therapy due to COVID-19 pandemic related delays for elective surgery. Despite being a long-term treatment, cinacalcet was generally well tolerated. The quantitative reduction seen in serum adjusted calcium correlates with existing literature and highlights the benefit of cinacalcet as the mainstay of medical management of hypercalcaemia of pHPT for those unable to have surgery.