Emerging Combination Therapy of Empagliflozin and Finerenone for the Management of Type 2 Diabetes Mellitus Associated with Chronic Kidney Disease: Therapeutic Rationale & Formulation Perspectives

Table 1: Summary of drugs for prevention and treatment of DKD ^[12-15]

However, significant residual renal and cardiovascular risk persists in many patients with DKD, alongside challenges such as treatment-related adverse effects, risk of hyperkalaemia. ^[16] These limitations highlight the need for optimized combination therapies and more effective treatment strategies.

Rationale and Objective of the Present Review

The combination of Empagliflozin, a sodium-glucose cotransporter-2 inhibitor, and Finerenone, a non-steroidal mineralocorticoid receptor antagonist, represents a promising strategy for patients with type 2 diabetes mellitus associated with chronic kidney disease ^[17-18].

The combination targets complementary pathways involved in DKD progression and may provide enhanced renal and cardiovascular benefits compared with monotherapy. ^[19]

Beyond its therapeutic potential, the combination also presents opportunities for the development of a fixed-dose combination (FDC) aimed at improving treatment adherence and simplifying complex medication regimens. Therefore, this review discusses the therapeutic rationale, clinical evidence, and formulation perspectives supporting the Empagliflozin –Finerenone combination in the management of DKD.

2. PATHOPHYSIOLOGICAL MECHANISMS IN T2DM- ASSOCIATED CKD

The pathophysiology of Diabetic kidney disease development and progression is complex and multifactorial, as diabetes‑induced hyperglycemia activates a spectrum of pathological pathways within the kidney, including haemodynamic, metabolic, inflammatory, fibrotic, and oxidative stress mechanisms.

Glomerular Hyperfiltration and Hemodynamic Stress

Glomerular hyperfiltration is an early hallmark of diabetic kidney disease (DKD), characterized by increased intraglomerular pressure and elevated single-nephron GFR. ^[20]

There are three interlinked pathways that contributes to this maladaptive state:

• Ultrastructural perspective: In early diabetes, renal hypertrophy occurs, mainly due to proximal tubular enlargement and enlarged nephrons. These structural changes result in an increase in the kidney volume and filtration surface area, leading to increased GFR. Moreover, tubular hypertrophy often occurs before the rise in GFR, indicating a causal relationship. ^[21-22]
• The Vascular Theory: Hyperfiltration results from an imbalance in vasoactive mediators. ^[21] Hyperglycemia enhances the production of vasoactive mediators such as nitric oxide (NO), cyclooxygenase-2 (COX-2)–derived prostanoids, angiotensin II and endothelin-1, causing afferent vasodilation and efferent vasoconstriction. This combined effect results in increased intraglomerular pressure and increased GFR. ^[23]
• The Tubular Theory: This is the central mechanism that focuses on the impairment of Tubuloglomerular Feedback (TGF). Increased SGLT2 mediated proximal tubular sodium-glucose reabsorption reduces sodium delivery to the macula densa, suppressing TGF and promoting glomerular hyperfiltration. ^[24]

Fig.1. Illustration of glomerular hyperfiltration and hemodynamic stress in DKD

Metabolic Dysregulation and Oxidative Stress

Oxidative stress, resulting from an imbalance between reactive oxygen species (ROS) production and antioxidant defence system, is the major contributor of DKD. Persistent hyperglycemia increases ROS production in the mitochondria, causing oxidative stress. ^[25]

During oxidative phosphorylation, electrons from NADH and FADH₂ are transferred via the electron transport chain (ETC) to reduce oxygen to water. ^[26] Under hyperglycemic state, excessive electron flux causes leakage at complexes I and III, producing ROS like superoxide anions that are then converted into hydrogen peroxide. ^[27] This process, facilitated by additional enzymatic sources, causes the ROS overproduction and subsequent cellular damage. ^[28]

A convergence of hyperglycemic metabolic dysfunctions further induces oxidative stress. The Polypol pathway, where aldose reductase converts glucose to sorbitol, depleting NADPH and reducing antioxidant capacity while inducing oxidative stress ^[29] , the accumulation of advanced glycation end-products (AGEs) which forms a destructive loop with ROS ^[30] , and increased flux through the hexosamine pathway which produces UDP-GlcNAc, driving protein O-glycosylation and contributing to endoplasmic reticulum stress and inflammation. ^[31]

Together, these processes culminate in mitochondrial dysfunction and a self-amplifying cycle of ROS production, ultimately leading to small vessel lesions and progressive renal injury.

Fig.2. Illustration of metabolic dysregulation and oxidative stress in DKD

Chronic Inflammation and Tubulointerstitial Fibrosis: Role of Mineralocorticoid Receptor

In DKD, the mineralocorticoid receptor (MR), which usually controls the balance of salt and water, becomes pathologically overactive in immune cells and podocytes. Inflammatory and fibrotic cascades are initiated by this abnormal activation, accelerating renal damage and decline.

Pro-inflammatory and Pro-fibrotic signalling: Prolonged MR activation stimulates inflammatory cytokines like NF‑κB, IL‑1β, and TNF‑α, and also upregulates mediators such as TGF‑β1, PAI‑1, CTGF, collagen, and fibronectin. Together, these signals increase tissue damage and induce fibrosis. ^[32]

Oxidative stress loop:MR increases NADPH oxidase activity, producing ROS and causing mitochondrial dysfunction. ^[33] Even in the absence of aldosterone, these ROS re-activate MR through Rac1 signalling, creating a vicious cycle of oxidative stress and receptor overactivation. ^[34]

Structural Remodelling: Aldosterone further promotes remodelling by polarizing macrophages into a pro-inflammatory state and converting fibroblasts into myofibroblasts. This promotes tubulointerstitial fibrosis and tubular atrophy, the two major causes of renal decline in DKD. ^[35]

3. EMERGING PHARMACOTHERAPEUTIC STRATEGIES IN DIABETIC KIDNEY DISEASE
   1. Empagliflozin : A Sodium–Glucose Cotransporter-2 (SGLT2) Inhibitor

Empagliflozin  is an oral SGLT2 inhibitor approved for adults with type 2 diabetes mellitus (T2DM). ^[36] It reduces the reabsorption of glucose and sodium and increases glycosuria by selectively inhibiting SGLT2 in the S1 segment of the proximal renal tubule. It is also effective in insulin-resistant conditions because of its insulin-independent action. ^[37]

Renal Protective Mechanisms

Empagliflozin produces nephroprotective benefits through hemodynamic, metabolic, antioxidant mechanisms ^[38] By reducing proximal tubular sodium reabsorption and increasing distal delivery to the macula densa, TGF is restored, lowering intraglomerular pressure and glomerular hyperfiltration. ^[39] Other nephroprotective effects include suppression of RAAS, decreased arterial stiffness, lower serum uric acid and attenuation of oxidative stress, collectively slowing CKD progression. ^[40]

Cardiovascular Protective Mechanisms

Empagliflozin improves cardiovascular outcomes by natriuresis, osmotic diuresis, and inhibition of sodium-hydrogen exchangers (NHE1/NHE3), even though there is no direct cardiac SGLT2 expression. ^[40] Additionally, it also reduces plasma volume and total body sodium, and promotes mild weight loss. ^[41]

By promoting mild ketone utilization, it may further enhance myocardial and renal energy efficiency. ^[42]

Key Clinical Evidence

• The EMPA-REG OUTCOME trial showed significant reductions in major adverse cardiovascular events (MACE), cardiovascular mortality, and hospitalization for heart failure in patients with T2DM at high cardiovascular risk. ^[43] Further renal analyses confirmed a reduced risk of kidney disease progression and major renal outcomes. ^[44]
• The EMPA-KIDNEY trial demonstrated a significant reduction in CKD progression and cardiovascular death, along with preservation of estimated glomerular filtration rate (eGFR), irrespective of diabetes status. These findings establish Empagliflozin as a cornerstone therapy in T2DM-associated CKD, extending benefits beyond glycemic control. ^[45]

Clinical Adoption

KDIGO 2022 and ADA 2025 guidelines recommend Empagliflozin as foundational therapy in T2DM-associated CKD due to consistent renal and cardiovascular benefits demonstrated in clinical trials and real-world studies.

3.2 Finerenone: A Non-Steroidal Mineralocorticoid Receptor Antagonist (nsMRA)

Finerenone is a selective, nsMRA approved for the treatment of CKD associated with T2DM. Its distinct non-steroidal structure enables high-affinity and selective MR binding and blocks the binding of aldosterone, a component of the renin-angiotensin aldosterone-system (RAAS) , preventing the recruitment of transcriptional coactivators which are responsible for driving aldosterone-mediated pro-inflammatory and pro- fibrotic gene expression. ^[46]

Renal and Cardioprotective Mechanisms:

Finerenone slows the progression of DKD mainly by inhibiting pathological MR overactivation. It attenuates glomerulosclerosis, tubulointerstitial fibrosis, and vascular remodeling by lowering inflammatory cytokines (TNF-α, IL-6) and fibrotic mediators (TGF-β, collagen IV). ^[47] It significantly lowers the urinary albumin-to-creatinine ratio (UACR), a crucial marker of renal damage and cardiovascular risk. It also exhibits hemodynamic neutrality, with minimal effects on intraglomerular hemodynamics and systemic blood pressure. ^[48]

Key Clinical Evidence:

The clinical utility of Finerenone in DKD has been established through the large-scale FIDELITY pooled analysis, which combined data from two landmark phase III trials:

• FIDELIO-DKD: This trial focused on patients with predominantly advanced CKD and T2DM. It demonstrated that Finerenone significantly reduced the risk of the primary composite renal outcome (kidney failure, a sustained decrease in eGFR of ≥40%, or death from renal causes) and decreased the risk of cardiovascular events. ^[49]
• FIGARO-DKD: This study included patients with earlier stages of CKD (Stage 1-4 with albuminuria). It highlighted Finerenone’s cardiovascular benefits, specifically showing a significant reduction in the risk of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, or hospitalization for heart failure. ^[50]

A pooled analysis of these trials (FIDELITY) confirmed the benefit of Finerenone for both primary and secondary prevention of cardiovascular events in patients with CKD and T2DM on top of a background of optimized renin–angiotensin system inhibitor therapy with well-controlled blood pressure and blood glucose levels. ^[51]

Collectively, these trials establish Finerenone as a key therapy for DKD, offering a direct pathway to address inflammation and fibrosis that remains unaddressed by standard-of-care ACE inhibitors or ARBs.

Table 2: Marketed Formulations of Empagliflozin And Finerenone

4. THERAPEUTIC RATIONALE FOR COMBINATION THERAPY

4.1 Complementary and Synergistic Mechanisms

Empagliflozin and Finerenone together target complementary pathophysiological mechanisms involved in T2DM-associated CKD. Empagliflozin primarily modulates renal hemodynamics by restoring TGF and lowering intraglomerular pressure, while Finerenone inhibits MR overactivation, thereby suppressing downstream pro-inflammatory and pro-fibrotic signaling. This dual approach allows for a more comprehensive approach to slowing the disease progression compared to monotherapy.

4.2 Mitigation of Compensatory Mechanisms

While monotherapy provides significant benefits, it may leave a substantial residual cardiorenal risk due to persistent pathological processes such as aldosterone breakthrough or sustained glomerular hyperfiltration. Combined therapy allows for simultaneous mitigation of these maladaptive pathways.

Fig.3. Proposed mechanisms for reducing adverse cardiovascular‑ and kidney‑related outcomes based on preclinical and clinical studies using Finerenone and SGLT2 inhibitors. Adapted from Green JB et al., Nephrol Dial Transplant, 2023. ^[52]

5. CLINICAL EVIDENCE: The CONFIDENCE (COmbinatioN effect of Finerenone anD Empagliflozin in participants with CKD and type 2 diabetes using a UACR Endpoint) Trial

5.1 Study Design and Objectives

The CONFIDENCE trial was a multicentre, randomized, double-blind study evaluating the safety and efficacy of combined Empagliflozin and Finerenone therapy in patients with T2DM and CKD. The primary endpoint was reduction in UACR, and the secondary endpoints were changes in eGRF and cardiovascular outcomes.[53]

5.2 Efficacy Outcomes

At 180 days, combination therapy resulted in significant reductions in UACR compared to monotherapy, with reductions of 29% versus Finerenone alone and 32% versus Empagliflozin alone (P < 0.001). Benefits were consistent across KDIGO risk groups, with supportive evidence for better renal function preservation. ^[53]

5.3 Safety and Tolerability

There were no new or additional safety concerns found and the combination was well tolerated. While the kaliuretic effect of SGLT2 inhibitors like empagliflozin is known to off-set MRA induced potassium retention, a secondary analysis of the CONFIDENCE trial indicated that the combination resulted in a numerically lower, though not statistically significant, incidence of hyperkalemia (15.1%) compared to finerenone monotherapy (18.8%). Importantly, the treatment benefits were maintained regardless of hyperkalemia status. Other adverse events, including volume depletion and hypotension remained low, and initial eGFR declines were mild and reversible. ^[53]

5.4 Subgroup Analyses

The efficacy and safety profile of the combination therapy was consistent across multiple subgroups, including variations in baseline eGFR, albuminuria, age, KDIGO risk categories, and background RAAS inhibitor therapy, supporting its broad clinical applicability. ^[54]

6. CLINICAL IMPLEMENTATION

When transitioning from monotherapy treatment to a dual pathway regimen, a careful strategy is needed to minimize potential safety hazards and maximize nephroprotective and cardioprotective effects for patients.

Therapy sequencing and introduction:

Due to high residual risk in DKD patients, the current clinical opinion for 2026 recommends giving priority to rapid sequencing. The CONFIDENCE trial protocol recommends the following two approaches:

Simultaneous introduction of both medications: Starting both Empagliflozin (10 mg) and Finerenone (10 or 20 mg) concurrently. The strategy is recommended for high-risk patients with increased albuminuria in order to achieve rapid reduction in UACR. ^[53]

Staggered introduction: Starting an SGLT2 inhibitor followed by introduction of ns-MRA after 4–8 weeks. This allows clinicians to observe the effect on hemodynamic eGFR drop from one medication before introducing another drug into the therapy. ^[55]

Dosages and Titrations

Empagliflozin: The therapy is typically initiated and maintained using the standard dosage (10 mg).

Finerenone:

The dosing depends on the current state of eGFR. Patients with eGFR ≥ 60 mL/min/1.73 m² are recommended to begin with the dosage of 20 mg PO daily, while those between 25–60 mL/min/1.73 m² start at 10 mg PO daily, with a goal to uptitrate to 20 mg based on serum potassium levels. Initiation of Finerenone is not recommended in patients with eGFR < 25 mL/min/1.73m² as clinical experience is limited. In patients with end-stage renal disease (eGFR < 15 mL/min/1.73m²), discontinue Finerenone treatment as clinical experience is limited ^[56]

Monitoring Protocols:

To ensure safety, a standardized monitoring is recommended:

Potassium Monitoring: Serum potassium (K⁺) should be assessed 4 weeks after initiation or dose titration. Initiation is contraindicated if K⁺ > 5.0 mEq/L. ^[56]

The "hemodynamic dip": A mild, reversible decline in eGFR is expected. Routine monitoring should continue, but therapy generally remains unchanged unless the eGFR decline exceeds 30% from baseline.  ^[55]

Volume Status: Clinicians must monitor for signs of volume depletion (e.g., symptomatic hypotension, dizziness) secondary to the osmotic diuretic effect of Empagliflozin. This is particularly critical in patients concurrently treated with high-dose loop diuretics. ^[53]

The clinical implementation of this dual-pathway approach could be further optimized through the development of a Fixed-Dose Combination (FDC), supporting patient-centric treatment strategies.

7. TARGET PATIENT POPULATION

The Empagliflozin –Finerenone fixed‑dose combination is intended for patients with type 2 diabetes mellitus (T2DM) complicated by chronic kidney disease (CKD), particularly those at elevated cardiorenal risk. Based on pivotal trial inclusion criteria and guideline recommendations, the ideal candidate profile includes:

• T2DM with CKD and albuminuria (UACR ≥30 mg/g; with ≥300 mg/g indicating severe risk)
• Currently receiving ACEi/ARB therapy as standard of care
• Estimated glomerular filtration rate (eGFR) ≥25 mL/min/1.73 m²
• Serum potassium ≤5.0 mEq/L to minimize hyperkalemia risk
• High cardiorenal risk patients, including those with persistent albuminuria or established cardiovascular disease

This population reflects the cohorts studied in FIDELIO‑DKD, EMPA‑KIDNEY, and CONFIDENCE, where dual therapy demonstrated synergistic renal and cardiovascular protection. Careful patient selection is essential to maximize therapeutic benefit while mitigating risks such as hyperkalemia or volume depletion. [49,53,57]

8. FORMULATION PERSPECTIVES AND CHALLENGES
   1. Pharmacokinetics and Pharmacodynamics (PK/PD) of the combination

Empagliflozin and Finerenone exhibit favorable pharmacokinetic compatibility with minimal potential for drug–drug interactions. Empagliflozin is metabolized mainly via uridine diphosphate glucuronosyltransferase (UGT) pathways ^[58], while Finerenone undergoes hepatic metabolism through CYP3A4, reducing overlap in metabolic pathways. ^[59]

From a pharmacodynamic perspective, the combination integrates hemodynamic modulation with anti-inflammatory and antifibrotic effects, thereby enhancing overall comprehensive therapeutic protection. ^[53]

Despite favourable pharmacokinetic compatibility, the combination requires careful clinical monitoring because Finerenone may increase hyperkalemia risk and Empagliflozin may contribute to volume depletion and transient eGFR decline.

Overall, the complementary and synergistic PK/PD characteristics of Empagliflozin and Finerenone support their combined use, although clinical and formulation considerations must be addressed to optimize safety and efficacy.

1. 2. Development of Fixed- Dose Combination (FDC)

Advancing toward a fixed‑dose combination (FDC) of Empagliflozin and Finerenone offers a promising strategy for patients with T2DM and CKD. However, their distinct physicochemical and solubility characteristics present formulation challenges.

In order to maintain therapeutic bioequivalence and long-term stability, advanced formulation approaches such as bilayer tablets and concentric “tablet-in-tablet” are essential to enable spatial separation of APIs, tailored release kinetics, thereby ensuring dose proportionality across titration levels.

Despite the established clinical synergy between Empagliflozin and Finerenone, a FDC of these agents is not yet commercially available, representing a significant opportunity to address current barriers in medication adherence and pill burden. If successfully developed, an Empagliflozin –Finerenone FDC would represent a paradigm shift in the treatment of DKD, offering a streamlined, patient‑centric approach that aligns with the growing emphasis on precision and combination therapy in complex chronic diseases.

Table 3: Physicochemical and Biopharmaceutical Properties Supporting Empagliflozin –Finerenone FDC Development ^[53,61]