Effect of Esaxerenone on UACR Across Different Levels of Albuminuria: A Comprehensive Review

Abstract

Esaxerenone, a novel nonsteroidal mineralocorticoid receptor antagonist (MRA), has garnered significant attention for its renoprotective effects in patients with chronic kidney disease (CKD) and diabetes mellitus, particularly regarding its impact on urinary albumin-to-creatinine ratio (UACR) across varying degrees of albuminuria. This review synthesizes current clinical evidence from recent trials and real-world studies, elucidating the efficacy, safety, and practical implications of esaxerenone therapy in reducing albuminuria, slowing renal progression, and optimizing patient outcomes. Mechanistic insights, risk stratification, current guideline recommendations, and future directions are discussed to provide clinicians with a comprehensive, evidence-based understanding of esaxerenone in nephroprotection.

Introduction

Chronic kidney disease (CKD) represents a major global health challenge, with albuminuria serving as a critical biomarker and predictor of renal and cardiovascular outcomes. The management of increased urinary albumin excretion remains a cornerstone in slowing CKD progression and reducing associated morbidity. Esaxerenone, an innovative, selective, nonsteroidal MRA, offers a new therapeutic avenue for patients with diabetic and non-diabetic CKD by targeting the mineralocorticoid pathway implicated in renal fibrosis and proteinuria. This review explores the evidence for esaxerenone’s effect on UACR across the spectrum of albuminuria, emphasizing mechanistic rationales, clinical trial data, and practical implications for nephrology practice.

Epidemiology / Disease Burden

CKD affects approximately 10–12% of the global adult population, with rates of diabetes and hypertension—primary drivers of CKD—continuing to rise. Albuminuria, defined by elevated UACR, is prevalent in up to 40% of individuals with diabetes and is a strong independent risk factor for CKD progression and cardiovascular disease. The burden of albuminuria is not limited to overt nephropathy but extends to microalbuminuria stages, where evidence-based interventions can yield significant clinical benefit. Despite advances in renin-angiotensin-aldosterone system (RAAS) blockade, residual albuminuria remains common, underscoring the need for adjunctive therapies such as esaxerenone.

Pathophysiology

Albuminuria results from glomerular barrier dysfunction and impaired tubular reabsorption, often secondary to chronic hyperglycemia, hypertension, and aldosterone-mediated renal injury. Mineralocorticoid receptor activation promotes inflammation, oxidative stress, and fibrosis within the renal parenchyma, exacerbating proteinuria and accelerating nephron loss. Esaxerenone, by selectively inhibiting mineralocorticoid receptor signaling, attenuates these maladaptive processes, thereby reducing glomerular injury and lowering UACR. Its nonsteroidal structure confers enhanced selectivity and minimized off-target effects compared to traditional steroidal MRAs.

Risk Factors

Risk factors for albuminuria and progressive CKD include poorly controlled diabetes, hypertension, genetic predisposition, smoking, obesity, and dyslipidemia. Persistent elevation of aldosterone despite RAAS inhibition ("aldosterone breakthrough") is increasingly recognized as a contributor to ongoing renal injury. Identifying patients with high baseline UACR, rapid eGFR decline, or refractory hypertension is crucial for optimizing therapeutic interventions such as esaxerenone.

Clinical Features

Patients with elevated UACR may initially be asymptomatic or present with subtle signs such as nocturia or hypertension. As albuminuria progresses, clinical manifestations of nephrotic syndrome, edema, and declining renal function may emerge. Importantly, even low-grade (micro-)albuminuria is associated with increased cardiovascular risk and warrants aggressive risk factor modification.

Diagnosis

The quantification of albuminuria is achieved via measurement of UACR in a spot urine sample, with thresholds defined as normal (<30 mg/g), microalbuminuria (30–299 mg/g), and macroalbuminuria (≥300 mg/g). Repeated testing is required to confirm elevation and to monitor response to therapy. Comprehensive assessment should include evaluation of eGFR, blood pressure, glycemic control, and exclusion of secondary causes of proteinuria.

Treatment & Management

First-line management of albuminuria in CKD includes optimal control of blood pressure (preferably with RAAS inhibitors), glycemic targets in diabetes, lipid lowering, weight management, and lifestyle modifications. Despite these interventions, residual albuminuria is common. Esaxerenone, administered once daily, has demonstrated significant additive reduction in UACR when combined with standard therapy, without substantial risk of hyperkalemia or acute kidney injury compared to traditional MRAs. Dosage adjustments and regular monitoring are essential to ensure safety and maximize renoprotection.

Recent Advances / Emerging Therapies

Recent randomized controlled trials such as the ESAX-DN and other phase 3 studies have substantiated the efficacy of esaxerenone in reducing UACR across a spectrum of albuminuria, including patients with microalbuminuria and those with overt nephropathy. Notably, esaxerenone achieved sustained and clinically meaningful reductions in UACR irrespective of baseline albuminuria, with a favorable safety profile. Emerging data suggest potential synergy with sodium-glucose co-transporter 2 (SGLT2) inhibitors and endothelin receptor antagonists, highlighting esaxerenone’s role in multifactorial renoprotection

Guideline Recommendations

Current guidelines from the Kidney Disease: Improving Global Outcomes (KDIGO) and regional nephrology societies increasingly recognize the value of MRAs in high-risk CKD populations with persistent albuminuria. Esaxerenone is endorsed as a suitable adjunctive therapy for patients with type 2 diabetes and CKD who have inadequate UACR response to RAAS blockade, with careful consideration of potassium monitoring and renal function. Ongoing guideline updates may further expand its indications as trial evidence accumulates.

Conclusion

Esaxerenone represents a significant advancement in the management of albuminuria and CKD progression. Its robust, consistent effects on UACR reduction across different albuminuria strata, combined with a favorable safety and tolerability profile, position it as a valuable tool in the nephrologist’s therapeutic arsenal. Integration of esaxerenone into clinical practice should be individualized, with risk stratification, vigilant monitoring, and attention to comorbidities guiding therapy. Ongoing research will clarify its long-term renoprotective benefits, optimal patient selection, and role in combination regimens for comprehensive CKD management.