Role of Finerenone in African American Veterans With Diabetic Kidney Disease

Chronic kidney disease (CKD) is a complex medical condition imposing deleterious effects on multiple organ systems. Prevention of increased cardiovascular mortality and progression to end-stage kidney disease (ESKD) are two major unmet medical needs in patients with CKD, with or without diabetes mellitus, especially in those with albuminuria. In patients with Diabetic Kidney Disease (DKD), the cornerstone of management includes blood pressure control, proteinuria management, maintenance of normal body weight, dietary adherence, and avoidance of nephrotoxic drugs. The management of DKD has undergone extensive changes with the advent of several foundational classes of guideline-based medical therapies (GDMT) for DKD. These include SGLT2i, GLP1-RAs along with Renin-Angiotensin System-inhibitors (RASi). While the benefits of the SGLT2i class of diabetes medications such as Empagliflozin for cardio-kidney outcomes in CKD are well recognized from the landmark EMPA-REG trial, there is less understood in terms of mechanisms of benefit, especially in high-risk patient phenotypes for progression to kidney failure, such as APOL1 positive gene mutation. The results from the recent FIDELIO-DKD and FIGARO-DKD studies showed that finerenone (an aldosterone receptor inhibitor) resulted in a decreased risk of cardiovascular events and slows down CKD progression in patients with type 2 diabetes (T2DM). This was a significant breakthrough and adds an additional class of medication for the treatment of DKD. However, the generalizability of the findings was limited as only 4.7% of the patients were African-American.

The Veterans Health Administration is the largest integrated healthcare system in the USA providing a comprehensive database of patients with CKD. The Nephrology and Endocrinology divisions at DC VAMC manage 175 new CKD patients each month (of whom 70% have diabetes) and 95% are African Americans. African Americans suffer from CKD at significantly higher rates and account for more than 35% of all patients receiving dialysis in the United States. Aggressive management with newer T2DM meds with reno-protective effects is important to be started early. Recently identified genetic variants in the APOL1 gene, found mostly in African Americans may explain a significant proportion of the rising burden of albuminuric CKD in African Americans. APOL1 risk variants G1 and G2 are trypanolytic factors that protect against trypanosomiasis in continental Africa but are associated with a significantly higher risk for the development of podocytopathy and ultimately progressive CKD. Though CKD is quite prevalent in African American patients, the precise mechanism of APOL1 risk variants leading to the progression of DKD in this patient population is unknown and requires further investigation. Interestingly the studies on APOL1 nephropathy have established an association with podocytopathy. Abnormalities in podocyte biology play a central role in the pathogenesis of albuminuric CKD. In CKD with albuminuria, podocyte injury is a key component in the pathophysiology of albuminuric CKD, which is also accompanied by systemic inflammation. The degree of podocyte injury is currently best assessed by kidney biopsy, which is an invasive procedure and not performed in the vast majority of patients with CKD. Therefore, the patterns and extent of podocyte injury in albuminuric CKD is less well understood. The investigators and others have shown improved endothelial function and decreased podocyte-specific urine protein injury markers production with SGLT2i in DKD. Additionally, the literature suggests close crosstalk between the glomerular vascular endothelium and the podocyte. The effect of Finerenone and SGLT2i on markers of podocyte injury, as well as markers of endothelial dysfunction (injury/inflammation) deserve further elucidation, either each medication on its own or in combination in African Americans with proteinuria.

The comparator in this study is Empagliflozin which is a standard of care in DKD. However, the investigators hypothesize that the combination will be more efficacious that either medication alone and synergistic for podocytopathy and proteinuria reversal similar to CONFIDENCE trial even in a CKD prone population of African Americans with diabetes