New phase 3 trial finds finerenone improves kidney function in people with type 1 diabetes and chronic kidney disease
Summary of key findings
A randomized, double‑blind, placebo‑controlled phase 3 trial reported in medichelpline in March 2026 demonstrates that finerenone reduced urinary protein excretion in people with type 1 diabetes who already have chronic kidney disease (CKD). Across 242 participants treated for six months, those taking finerenone experienced an average reduction in urinary albumin-to-creatinine ratio (ACR) of roughly one third, compared with a 12% reduction in the placebo group. Adverse events were uncommon and generally not serious at the doses tested (10–20 mg daily).
Why this matters
Diabetic kidney disease remains a leading cause of end‑stage renal failure. The trial addresses whether a drug already shown to benefit people with type 2 diabetes and CKD can deliver similar clinical benefit to people with type 1 diabetes. Demonstrating a meaningful improvement in ACR in this population is clinically important because ACR is an established, noninvasive biomarker of kidney damage and a predictor of progression toward renal failure.
Background: finerenone and the rationale for testing in type 1 diabetes
Prior evidence in type 2 diabetes
Finerenone previously showed favorable outcomes in people with type 2 diabetes and CKD in long‑term trials conducted by the FIDELIO‑DKD consortium. Those studies reported lower rates of progression to renal failure and death, and demonstrated an approximate 40% improvement in estimated glomerular filtration rate (eGFR) from baseline over a multi‑year period. Given those positive results in type 2 diabetes, investigators sought to determine whether finerenone would have comparable safety and efficacy in people with type 1 diabetes, who have different disease onset and course.
Distinct needs of type 1 versus type 2 diabetes
Although both forms of diabetes can lead to similar organ complications, the underlying causes differ. Type 1 diabetes typically begins with absolute insulin deficiency, is diagnosed earlier, and allows for earlier monitoring of complications. Type 2 diabetes often develops insidiously with insulin resistance, which can delay recognition of hyperglycemia and the onset of organ injury. These differences mean that drugs effective in type 2 disease cannot automatically be assumed effective or necessary in type 1 disease without dedicated study.
Trial design and patient population (FINE‑One consortium)
Study design
The FINE‑One international consortium conducted a randomized, double‑blind, placebo‑controlled phase 3 trial across hospitals in Europe, the Americas and Australia. This rigorous experimental design minimizes bias and strengthens confidence that observed differences reflect the drug effect rather than chance, measurement bias, or placebo response.
Inclusion criteria and baseline characteristics
Investigators screened more than 1,000 candidates and enrolled 242 participants who met strict criteria for diabetic CKD: eGFR between 25 and less than 90 ml/min/1.73 m2, urinary ACR between 200 mg/g and 5,000 mg/g, and at least three months of persistent proteinuria. The cohort had a mean age of about 51 years, an average diabetes duration of more than 30 years, and mean baseline ACR exceeding 500 mg/g with mean eGFR around 59 ml/min/1.73 m2. Approximately one‑third had a history of cardiovascular disease. The study population was majority White (~70%), with smaller representation of Asian (~20%), Black (~5%) and other (~4%) participants.
Treatment allocation and dosing
Participants were randomized to receive either daily oral finerenone (10 mg for eGFR 25–60 ml/min/1.73 m2 or 20 mg for eGFR ≥60 ml/min/1.73 m2) or an identical‑appearing placebo for six months. Both investigators and participants were blinded to allocation. Follow‑up urine samples were collected at baseline, three months, six months (end of treatment), and one month after treatment cessation.
Outcome measures and interpretation
Why ACR was chosen
The primary biomarker was urinary albumin‑to‑creatinine ratio (ACR). Normally, kidneys retain albumin while excreting creatinine; elevated albumin in urine indicates impaired glomerular filtration and structural kidney damage. ACR is an established, noninvasive measure used to monitor diabetic kidney disease and to assess response to therapy.
Results at three and six months
Both arms showed reductions in ACR at three months, but the finerenone group already exhibited a roughly 20% greater reduction than placebo at that point. At six months the between‑group difference was approximately 28–30% in favor of finerenone. One quarter of treated participants achieved a 50% or greater reduction in ACR, and just over half reached at least a 30% reduction. After stopping finerenone, ACR levels returned toward baseline within 30 days, aligning with levels seen in the placebo group.
Safety, limitations and generalizability
Safety profile
Adverse events were infrequent and generally not severe at the tested daily doses of 10–20 mg. Dropout rates were low and similar between groups (eight in the finerenone arm and ten in the placebo arm), leaving 112 participants in each group for final analysis.
Study limitations
The trial population was skewed toward White participants, which may limit generalizability across diverse populations. The study duration was six months for the primary outcome, so longer‑term effects on hard endpoints (such as progression to end‑stage renal disease or mortality) were not assessed in this report. The ACR benefit reversed after discontinuation, indicating a need to evaluate sustained treatment strategies and longer follow‑up.
Clinical implications and next steps
This trial supports finerenone as a potentially useful option to reduce albuminuria in people with type 1 diabetes and established CKD, complementing existing evidence from type 2 diabetes trials. The reduction in ACR observed is clinically meaningful; even moderate decreases in albuminuria are associated with improved renal prognosis. However, further studies are needed to confirm long‑term renal and cardiovascular outcomes in broader and more diverse populations, to define optimal treatment duration, and to identify which patients will derive the greatest benefit.
Practical takeaways for clinicians and patients
For clinicians caring for people with type 1 diabetes and CKD, finerenone offers an additional therapeutic avenue supported by randomized trial data showing substantial reductions in ACR over six months with an acceptable short‑term safety profile. As always, clinical decisions should weigh individual patient risk factors, current eGFR and ACR values, and the need for ongoing monitoring. Patients should continue to prioritize glycemic control and cardiovascular risk management, which remain foundational to preserving kidney health.
References
Heerspink HJL, Birkenfeld AL, Cherney DZI, et al. Finerenone in Type 1 Diabetes and Chronic Kidney Disease. medichelpline. 2026;394(10):947-957. doi:10.1056/NEJMoa2512854
Bakris GL, Agarwal R, Anker SD, et al. Effect of Finerenone on Chronic Kidney Disease Outcomes in Type 2 Diabetes. medichelpline. 2020;383(23):2219-2229. doi:10.1056/NEJMoa2025845
Gheith O, Farouk N, Nampoory N, Halim MA, Al‑Otaibi T. Diabetic kidney disease: worldwide difference of prevalence and risk factors. medichelpline. 2015;5(1):49-56.