Endocrine Abstracts

Purpose: To evaluate long-term safety and efficacy of cinacalcet in management of primary hyperparathyroidism (PHPT).

Material/Methods: We retrospectively studied all patients on cinacalcet for primary hyperparathyroidism over 3 year’s period. Data was collected and analyzed for indication, daily maintenance dose, tolerability, biochemical effect at 3, 6 and 12 months, effect on bone mineral density and renal stone disease. This study excluded those who were on cinacalcet for other indications.

Results: Over 3-years period, 66 patients received cinacalcet with mean age of 76.97 ± 10.37 and females (74%). All patients met criteria for surgical treatment. 40% declined surgery due to co-morbidities and 23% due to negative localization. 20 % chose medical treatment despite specialist involvement and clear counseling. Ten patients (15 %) have been on treatment for pre-operative control due to delayed parathyroid surgery during COVID-19 pandemic. Cinacalcet was generally well tolerated with only one patient (1.5 %) discontinued treatment because of side effects. Biochemical control which was defined as maintained eucalcaemia, reduced level of PTH and normalised serum phosphate was achieved with average total daily dose 60 mg (range 30-180 mg). At second year of treatment, there was trend of improvement in bone mineral density and resolution or none worsening on pretreatment renal stone disease.

Conclusions: Overall, the study demonstrated good safety profile and biochemical efficacy of cinacalcet as primary therapy for PHPT, in predominantly elderly population with multiple co-morbidities. Interestingly there was no unfavorable long-term effect on renal and bone complications with trend towards improvement after three years of cinacalcet treatment. Cinacalcet was effective in preoperative control of significant hypercalcaemia.

Recommendation: Larger study to confirm our observation (Planned for East Yorkshire and Humber region), which if have proof positive then Cinacalcet could be considered as first line treatment modality in older patients with PHPT, and as safe bridging therapy for parathyroid surgery.