Nonsteroidal Mineralocorticoid Receptor Antagonist Finerenone Significantly Reduces Albuminuria in Kidney Transplant Recipients: A Prospective Study

Background: Current therapeutic strategies for managing proteinuria after kidney transplantation remained limited. Finerenone, a novel nonsteroidal mineralocorticoid receptor antagonist (MRA) characterized by high selectivity, a nonsteroidal structure, and a lower risk of hormonal side effects, might have played a protective role in kidney transplant recipients (KTRs). This study aimed to assess the safety and efficacy of finerenone in reducing proteinuria and improving graft function in KTRs. Methods: This single-center, prospective cohort study consecutively enrolled KTRs who regularly received finerenone between January 2024 and January 2025. Adult KTRs with a urinary albumin-to-creatinine ratio (UACR) ranging from 300 mg/g to ≤5000 mg/g and an estimated glomerular filtration rate (eGFR) ≥25 mL/min/1.73 m2, with less than a 25% decline in graft function over the preceding 3 months, were included. Baseline data, laboratory parameters, and adverse events were collected. Results: A total of 44 adult KTRs were included in the analysis. The median baseline UACR was 1355 mg/g. After 1 month of finerenone treatment, the median UACR decreased to 1000 mg/g (p < 0.01). At 3 months, it further declined to 980 mg/g (p < 0.001), and at 6 months, to 801 mg/g (p < 0.01). By 9 months, the UACR remained significantly lower than baseline. Among the included KTRs, 2 discontinued treatment within 2 weeks due to hyperkalemia. One recipient discontinued therapy due to a 52.17% increase in serum creatinine. The eGFR levels of the remaining recipients were elevated at 9 months, though the difference was not statistically significant. Conclusion: This analysis suggested that finerenone significantly reduced albuminuria in KTRs and may have protected against the progression of kidney disease.