Finerenone as a Third-Line Therapy for Persistent Proteinuria in Diabetic Kidney Transplant Recipients

Proteinuria is a strong predictor of graft failure in kidney transplant recipients (KTRs). While non-steroidal mineralocorticoid receptor antagonists (NS-MRAs), particularly finerenone, have demonstrated renoprotective benefits in chronic kidney disease, KTRs were excluded from pivotal trials. Evidence on finerenone's safety and antiproteinuric effects in this population remains limited. This retrospective observational study evaluated 13 diabetic KTRs with persistent proteinuria despite optimized renin-angiotensin system blockade and sodium-glucose cotransporter 2 inhibitor therapy. Finerenone (10 mg/day) was added to standard care. Clinical and laboratory parameters, including estimated glomerular filtration rate (eGFR), serum electrolytes, total proteinuria, albuminuria, and their creatinine ratios, were assessed at baseline, 3 months, and 6 months. Safety outcomes focused on hyperkalemia and eGFR. Finerenone was discontinued in one patient due to hyperkalemia. In the remaining 12, 24-h proteinuria and urinary protein-to-creatinine ratio declined at 3 months and stabilized by 6 months. Conversely, no statistically significant changes were observed in albuminuria or the albumin-to-creatinine ratio. No clinically relevant changes occurred in eGFR, blood pressure, body weight, or serum electrolytes. This is the first study assessing finerenone in diabetic KTRs. Finerenone was well tolerated, was associated with an early reduction in proteinuria, and showed no adverse effects on graft function. These findings provide novel insights into the safety and potential role of finerenone in kidney transplant recipients.