Evaluating the Efficacy of Finerenone in Reducing Proteinuria in Diabetic Nephropathy Patients Receiving Maximum Tolerable Doses of Dapagliflozin and Telmisartan

Background Diabetic nephropathy (DN) remains a leading cause of end-stage renal disease (ESRD), with persistent proteinuria contributing to renal and cardiovascular complications. Despite dual therapy with renin-angiotensin-aldosterone system (RAAS) blockers and sodium-glucose co-transporter-2 inhibitors (SGLT2is), residual proteinuria persists in a substantial subset of patients. Finerenone, a novel nonsteroidal mineralocorticoid receptor antagonist (MRA), has shown promise in reducing albuminuria and slowing chronic kidney disease (CKD) progression. Unlike previous trials such as FIDELIO-DKD, this study evaluated the additive effect of finerenone exclusively in patients receiving maximum tolerable doses of both dapagliflozin and telmisartan. Objectives To evaluate the efficacy and safety of finerenone in reducing proteinuria in patients with DN and residual albuminuria, all of whom were receiving maximally tolerated background therapy with dapagliflozin and telmisartan. Methods This was a Retrospective, single-center observational study involving 33 patients with diabetic nephropathy and residual proteinuria. All patients received finerenone 10 mg daily for 24 weeks. Key parameters assessed at baseline and follow-up included urinary albumin-to-creatinine ratio (UACR), estimated glomerular filtration rate (eGFR), and serum potassium. Responders were defined as patients who exhibited a reduction in UACR at follow-up. Results The mean individual percentage change in UACR was − 7.3%. Twenty-two patients (66.7%) responded to treatment with a reduction in UACR, while 11 patients (33.3%) did not. When stratified by baseline albuminuria, responders with initial UACR < 1000 mg/g, 1000–3000 mg/g, and > 3000 mg/g showed average reductions of − 47.9%, − 39.0%, and − 32.8%, respectively, suggesting a gradient treatment effect. Finerenone was well tolerated. Mild hyperkalaemia (serum potassium > 5.0 mmol/L) occurred in 15.2% of patients, with no cases requiring treatment discontinuation. Renal function remained stable throughout the study. Conclusions Finerenone demonstrated clinically meaningful reductions in proteinuria, particularly in patients with moderate to severe baseline albuminuria, and was generally safe and well tolerated. These findings support the use of finerenone as part of a personalized, multimodal strategy for proteinuria management in diabetic nephropathy, particularly in patients already receiving optimized RAAS and SGLT2 inhibition. Future studies should further define predictors of response and assess long-term renal outcomes.