P1420IS THE CHANGE FROM CINACALCET TO ETELCALCETIDE SAFE AND EFFECTIVE IN PATIENTS ON HEMODIALYSIS WITH SECONDARY HYPERPARATHYROIDISM?
Authors: Hadad Arrascue Fernando , Araque Alicia , Amair Ruth , Rosique Florentina , Perez Perez Antonio , Andreu Muñoz Alberto , Cabezuelo-Romero Juan 
Published: June 2020

Abstract

Background and Aims
Vitamin D analogues stimulate the absorption of calcium and phosphorus, while calcimimetics reduce parathyroid hormone (PTH) without calcium and phosphorus elevation, which reduces the risk of vascular calcification.
However, the biggest problem of first-generation calcimimetics is the lack of adherence due to abandonment or non-compliance due to side effects and the high load of tablets taken by our patients.

Method
A prospective and exploratory 24-week study, which included 54 adult patients on chronic hemodialysis (3 times per week) with secondary hyperparathyroidism (PTH &gt;=150 pg/ml). Thirty-three patients were converted from cinacalcet to etelcalcetide, due to the lack of adherence to cinacalcet treatment and the inability to increase the dose due to the side effects of cinacalcet. The remaining 21 patients started etelcalcetide without previously taking cinacalcet.
The dose of etelcalcetide was done according to the baseline PTH value. PTH &gt;150 and &lt;=300 pg/ml, started with 5 mg of etelcalcetide per week, PTH &gt;300 and &lt;=500 pg/ml with 7,5 mg/week, PTH &gt; 500 and &lt;= 800 pg /ml with 10 mg/week, PTH &gt;800 pg/ml with 15mg/week.

Results
In the first four weeks, calcium decreased significantly, but subsequently remained stable for the rest of the study. From the baseline to the 24-week, serum calcium 8.85 ± 0.85 vs. 8.43 ± 0.83 mg/dl (p &lt;0.05), serum phosphorus 4.64 ± 1.46 vs. 4.51 ± 2.2 mg/dl (p&gt; 0.05).
PTH decreased significantly at the end of the study (718.4 ± 450 vs. 391.3 ± 232.7 pg/ml, p =0.03). PTH was reduced by 42% in the group that changed cinacalcet to etelcalcetide, and 50% in the group that did not take calciomimetics before the study.
At the beginning of the study, 61.1% of our sample also maintained paricalcitol as a treatment for secondary hyperparathyroidism. At the end of week 24, 51.8% maintained paricalcitol but with a significant reduction of 36.8% of the dose of paricalcitol (3.22 ± 3.78 mg/week), without significant changes in the dose of etelcalcetide at the end of the study (9.5 ± 1.3 mg/week) . No symptomatic hypocalcaemia was recorded throughout the study.
At week 12, the dose of etelcalcetide was reduced in 11% of patients and 7% at the end of week 24 due asymptomatic hypocalcemia.

Conclusion
Etelcalcetide showed a significant reduction in PTH with the optimization of therapeutic compliance.
In our population, the use of paricalcitol was reduced by 30% due to a progressive increase in the dose of etelcalcetide, keeping calcium levels stable and safe.
Asymptomatic hypocalcemia was the most observed side effect, but it is claimed that etelcalcetide has an even better safety profile than cinacalcet, with respect to digestive side effects.
It is advisable to use Etelcalcetide by individualizing the dose in each patient, depending on their levels of PTH and calcium.