Phase 3 FINE-ONE shows finerenone cuts protein in urine for type 1 diabetes CKD patients, with manageable safety, hinting at new kidney protection.
Finerenone significantly reduced albuminuria compared with placebo in adults with type 1
Among patients receiving background renin–angiotensin system blockade, treatment with the nonsteroidal mineralocorticoid receptor antagonist produced a 25% greater reduction in urinary albumin-to-creatinine ratio (UACR) over 6 months compared with placebo.
Journal: The New England Journal of Medicine
Publication Date: March 5, 2026
Study Design: Phase 3 randomized, double-blind, placebo-controlled trial
Population: 242 adults with type 1 diabetes and CKD with albuminuria
Intervention: Finerenone 10 mg or 20 mg daily
Primary Outcome: Relative change in urinary albumin-to-creatinine ratio at 6 months
Key Result: 25% greater reduction in albuminuria with finerenone vs placebo
“In this trial involving adults with type 1 diabetes and CKD, finerenone resulted in a significantly greater decrease in the urinary albumin-to-creatinine ratio than placebo over 6 months of treatment,” wrote the investigatory team, which was led by Hiddo Heerspink, PharmD, PhD, of the University of Groningen.
FINE-ONE was a phase 3, randomized, double-blind, placebo-controlled trial evaluating finerenone in adults with type 1 diabetes and CKD. The study enrolled 242 participants across 9 countries between February 2024 and February 2025. Eligible patients were aged 18 years or older with type 1 diabetes, estimated glomerular filtration rate (eGFR) of 25 to <90 mL/min/1.73 m², and albuminuria defined as a UACR of 200 to <5000. All participants were receiving stable therapy with either an ACE inhibitor or an ARB.
The primary endpoint was the relative change in UACR from baseline at 6 months. Baseline characteristics were similar between groups. Participants had a mean age of approximately 51 years, a mean eGFR of about 59 mL/min/1.73 m², and a median baseline UACR above 500 mg/g, indicating substantial kidney disease burden.¹
Treatment with finerenone resulted in significantly greater reductions in albuminuria compared with placebo. Median UACR declined from 574.6 at baseline to 373.5 at 6 months among participants receiving finerenone, compared with a decrease from 506.4 to 475.6 in the placebo group.¹
Overall, UACR decreased by 34% with finerenone and 12% with placebo, corresponding to a 25% greater reduction with finerenone (P < .001). Clinically meaningful reductions in albuminuria were also more frequent with finerenone. A decrease of at least 30% occurred in 54.3% of patients receiving finerenone compared with 32.7% of those receiving placebo. Reductions of at least 50% occurred in 28.4% and 21.8% of patients, respectively.¹
Overall adverse event rates were similar between treatment groups. Adverse events occurred in 47.1% of patients receiving finerenone and 49.2% receiving placebo, while serious adverse events occurred in approximately 12% in each group.¹
Hyperkalemia was the most common adverse event associated with finerenone, occurring in 10.1% of treated participants compared with 3.3% of those receiving placebo. Investigators pointed out 2 patients discontinued finerenone because of hyperkalemia.¹
Finerenone was associated with an early decline in eGFR. At 6 months, mean eGFR change from baseline was −5.6 mL/min/1.73 m² in the finerenone group compared with −2.7 mL/min/1.73 m² with placebo. Investigators reported that eGFR values approached baseline during a washout period after treatment discontinuation, suggesting a hemodynamic effect rather than structural kidney injury.¹
Type 1 diabetes affects an estimated 9.5 million people worldwide, and CKD remains a common and serious complication associated with elevated cardiovascular risk and premature mortality.¹ Despite improvements in diabetes management, therapeutic advances for diabetic kidney disease in type 1 diabetes have been limited, with renin–angiotensin system blockade remaining a cornerstone of therapy for more than three decades.²
Finerenone has previously demonstrated kidney and cardiovascular benefits in patients with type 2 diabetes and CKD in trials such as FIDELIO-DKD.³ The FINE-ONE trial therefore represents an early effort to extend mineralocorticoid receptor antagonism to patients with type 1 diabetes and diabetic kidney disease.
Editorialists accompanying the study noted that the findings mark an important step toward expanding treatment options for this population, although confirmation in larger and longer trials will be needed.²
Investigators noted several limitations within their trial to consider when interpreting results, including the trial’s 6-month duration and reliance on albuminuria as a surrogate endpoint are key limitations.¹ Additionally, the study was not designed to evaluate long-term outcomes such as kidney failure, dialysis initiation, or cardiovascular events.
In an editorial, Aleksandra Kukla, MD, and Marie C. Hogan, MD, PhD, both of the Mayo Clinic Rochester, highlight the need for future studies to determine whether reductions in albuminuria with finerenone translate into sustained improvements in kidney function and clinical outcomes. Ongoing research is also evaluating additional therapies, including sodium–glucose cotransporter 2 inhibitors and incretin-based agents, for kidney protection in type 1 diabetes.²
“The surge of therapies for diabetic kidney disease in persons with type 2 diabetes gives the nephrology community reason to hope that an accelerated drug-development pipeline will now address the full spectrum of diabetic kidney disease in persons with type 1 diabetes— including the substantial population with low or normal urinary albumin-to-creatinine ratios who remain at risk but were excluded from the FINE-ONE trial,” wrote the pair.
