#773 Upacicalcet preserves albumin levels in hemodialysis patients with secondary hyperparathyroidism: a post-hoc analysis of a randomized trial

Abstract Background and Aims Parathyroid hormone (PTH) induces browning of adipose tissue, leading to increased resting energy expenditure and wasting in animal models of kidney failure. However, its clinical significance remains unclear. The aim of this study was to investigate whether PTH-lowering therapy with upacicalcet, a novel injectable calcimimetic, affects serum albumin levels as a surrogate marker of wasting in hemodialysis patients with secondary hyperparathyroidism. Method This was a post-hoc analysis of a phase 3, double-blind, placebo-controlled study of upacicalcet for the treatment of secondary hyperparathyroidism in hemodialysis patients. Participants were randomized 2:1 to receive either upacicalcet or placebo after each hemodialysis session for 24 weeks. The slope of serum albumin levels for each participant was estimated using linear mixed models. Longitudinal changes in serum albumin levels were compared between the upacicalcet and placebo groups using mixed-effects models for repeated measures. Results A total of 99 patients in the upacicalcet group and 46 patients in the placebo group were included in the analysis. The mean baseline albumin level was 3.7 g/dL in both groups. Upacicalcet resulted in a significant reduction in intact PTH levels compared to placebo. While serum albumin levels showed a significant decline in the placebo group, they remained stable in the upacicalcet group, with slopes of −0.13 (−0.24 to −0.02) and −0.03 (−0.11 to 0.04) g/dL per year, respectively. Mixed-effects models for repeated measures showed a significant interaction between treatment and time regarding changes in albumin levels. Conclusion Our results indicate that PTH suppression with upacicalcet mitigates the gradual decline in albumin levels over time. Further research is needed to explore the long-term impact of PTH control on wasting and related outcomes.