Effect of Finerenone on Albuminuria in Type 1 Diabetes by Baseline HbA1c Level and Diabetes Duration: An Exploratory Analysis of the FINE-ONE Trial

OBJECTIVE: To evaluate whether the efficacy and safety of finerenone varied by baseline hemoglobin A1c (HbA1c) level, a proxy of glycemic control, and diabetes duration in people with type 1 diabetes and chronic kidney disease (CKD). RESEARCH DESIGN AND METHODS: Adults with type 1 diabetes, urinary albumin-to-creatinine ratio (UACR) 200 to <5,000 mg/g, and estimated glomerular filtration rate (eGFR) 25 to <90 mL/min/1.73 m2 were randomly assigned (one to one) to finerenone or placebo. UACR change from baseline over 6 months by baseline HbA1c and diabetes duration was analyzed. RESULTS: Baseline HbA1c was available for 240 of 242 participants; mean (SD) HbA1c, diabetes duration, and eGFR were 7.6% (1.1%; 60 [12] mmol/mol), 32.0 (14.2) years, and 58.9 (19.2) mL/min/1.73 m2, respectively. At 6 months, HbA1c (95% CI) remained unchanged (finerenone +0.03% [-0.14%, 0.20%]; placebo 0.00% [-0.12%, 0.11%]; between-group difference +0.04% [-0.17%, 0.24%]; P = 0.74). Over 6 months, median UACR decreased from 574.6 to 373.5 mg/g with finerenone and from 506.4 to 475.6 mg/g with placebo, corresponding to a -25% placebo-corrected change (95% CI -35%, -13%; P = 0.0001). Treatment effects were consistent across HbA1c tertiles (<7.1%, ≥7.1% to ≤8.1%, and >8.1%), with placebo-corrected UACR changes (95% CIs) of -17% (-40%, 13%), -18% (-39%, 10%), and -37% (-55%, -13%), respectively (P interaction = 0.41). Effects were similarly consistent across diabetes duration tertiles (P interaction = 0.70). Overall safety and incidence of hyperkalemia were similar across HbA1c tertiles. CONCLUSIONS: In adults with type 1 diabetes and CKD, finerenone reduced UACR and was well tolerated irrespective of HbA1c level or diabetes duration.