Endocrine Abstracts

Hypoparathyroidism is a rare disorder characterised by hypocalcaemia and insufficient or undetectable parathyroid hormone (PTH). Recombinant human PTH, rhPTH(1-84), has been approved in the United States and Europe as an adjunctive treatment for adult patients with hypoparathyroidism. When hypoparathyroidism is established, long-term administration of rhPTH(1-84) is a treatment option. Thus, long-term safety and efficacy data for rhPTH(1-84) are needed. To this end, we evaluated data from adults with hypoparathyroidism who previously participated in a single-arm, single-centre study known as HEXT (NCT00473265) and are now enrolled in a new phase 4 study (NCT02910466). Uninterrupted rhPTH(1-84) therapy has been maintained for 4.0 to 11.4 years. Baseline was the last assessment before starting rhPTH(1-84). Visit windows, defined as once every 6±3 months from baseline, were used for summary of assessments collected over time from medical records. If multiple measurements were recorded within a visit window, the value closest to the target day was used. Data are presented as mean ± S.D.. This cohort comprises 33 patients (53.4±12.4 years; 76% women; duration of hypoparathyroidism, 19.4±12.1 years). Mean duration of rhPTH(1-84) treatment was 7.5±2.3 years. Albumin-corrected serum calcium remained relatively stable during the treatment period and was near or within the target range for patients with hypoparathyroidism at most time points. Urinary calcium, serum phosphate, and serum creatinine were maintained within the target or normal ranges at all time points during rhPTH(1-84) treatment. Estimated glomerular filtration rate was between 60 and 89 ml/min per 1.73 m² at baseline and at most time points over the course of rhPTH(1-84) treatment. Calcium-phosphate product was 3.06±0.55 mmol²/l² at baseline and remained <4.4 mmol²/l² at all time points. This analysis includes the longest reported experience with rhPTH(1-84) for the treatment of hypoparathyroidism. The results document that rhPTH(1-84) treatment is characterised by maintenance of biochemical parameters, including stable renal function, within normal or target ranges for this disease. These data provide strong support for the efficacy of rhPTH(1-84) in the long-term management of hypoparathyroidism.