#1340 Transfer of patients from cinacalcet to etelcalcetide: a retrospective cohort study in real world practice

Abstract Background and Aims The prevalence of secondary hyperparathyroidism (SHPT) depends on the control strategy, primarily on achieving the target level of parathyroid hormone (PTH). According to materials from the KDIGO Controversies Conference (2023) on Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD), there is currently insufficient data to make a strictly justified choice of goals and strategies for SHPT correction. A retrospective, multicenter, cohort study was conducted to evaluate the effectiveness of ethelcalcetide in real-world practice. The aim of the study was to determine whether ethelcalcetide could effectively reduce PTH levels after 6 months of treatment in hemodialysis patients. The study also sought to identify baseline characteristics of CKD-MBD patients that predict whether they would achieve the desired therapeutic goal. Method The study included 302 hemodialysis patients who were treated with ethelcalcetide at 20 dialysis units in large city. The primary endpoint was the percentage of patients who achieved the target range of parathyroid hormone (PTH) levels six months after starting treatment (300–599 pg/mL) after unintended one-month washout period after cinacalcet use. The secondary endpoint was a decrease in absolute and relative PTH levels. The results were analyzed in subgroups based on baseline PTH levels (<600, 600–1000, and >1000 pg/mL) as well as in patients with and without evidence of autonomous parathyroid adenoma (a gland volume exceeding 500 mm³ or a maximum linear dimension greater than 10 mm, in combination with qualitative assessment of blood flow through the gland). Results Among the 302 patients included in the study, aged 56 ± 12 years (61% men), with a median dialysis duration of 36 months (Q1–Q3: 23–55 months), ranging from 6 to 132 months, and a baseline PTH level of 729 pg/mL (548–957 pg/mL), ranging from 287 to 1,473 pg/mL, and baseline calcium and phosphate levels of 2.35 mmol/L (0.25 mmol/L) and 1.97 mmol/L (0.47 mmol/L), respectively, the proportion of patients who achieved the target PTH range by the end of the follow-up period was 49.7%. The odds of achieving the target PTH value were higher for patients with a baseline PTH between 600 and 1,000 pg/mL compared to those with a PTH level above 1,000 pg/mL. Specifically, 79.3% of patients with baseline PTH levels between 600–1000 achieved the target level, compared to only 36.4% of those with PTH levels above 1000 (P < 0.001). Among patients with parathyroid adenomas, the frequency of achieving the target range was 48% for those with baseline PTH 600–1,000, compared to 85.6% for those without adenomas (P < 0.001). For patients with baseline PTH over 1000 pg/mL, the corresponding figures were 25% and 57.9%, respectively (P = 0.016). The presence of parathyroid adenoma (n = 63) was the most significant independent predictor of likelihood of achieving the target PTH level (OR = 0.3 [95%]) Conclusion Etelcalcetide treatment resulted in a decrease in PTH levels in most hemodialysis patients. No new side effects or drug intolerance were observed when transferring patients from cinacalcet to etelcalcetide. In patients with moderate SHPT (PTH 600–1000 pg/mL), it is possible to achieve the target PTH in most cases, but in those with higher baseline PTH levels, the outcome was worse. Signs of autonomous parathyroid adenoma better predict the lack of response to ethelcalcetide than high baseline PTH.