Diabetic kidney disease clinical trials: An analysis of current therapeutic approaches and enrollment landscape

Diabetic kidney disease (DKD) represents a significant public health challenge, affecting millions of individuals globally and serving as the leading cause of end-stage renal disease in developed nations. Contemporary clinical research has expanded dramatically over the past several years, with numerous trials investigating novel pharmacologic approaches aimed at slowing kidney function decline and reducing proteinuria in patients with type 2 diabetes and chronic kidney disease. This article provides an overview of the current landscape of diabetic kidney disease clinical trials, examining therapeutic targets, study populations, and clinical endpoints that define modern renoprotective research.

ANGPTL3 Inhibition and Combination Therapies in Phase 2 Development

One of the most notable emerging therapeutic approaches involves angiopoietin-like protein 3 (ANGPTL3) inhibition. The ANCHOR-POC trial, a Phase 2 randomized, double-blind, placebo-controlled study, is currently recruiting approximately 270 participants to evaluate the efficacy and safety of ALN-ANG3 (a small-interfering RNA) combined with evinacumab (an ANGPTL3 antibody) in adults with diabetic kidney disease 1. This study represents an innovative approach by combining two distinct mechanistic modalities targeting the same protein pathway. The trial is recruiting across multiple sites including locations in Alabama, Arkansas, California, and other states, with study contacts available through Regeneron Pharmaceuticals at 844-734-6643. The primary focus remains on assessing both the efficacy and safety profile of ANGPTL3 inhibition, along with pharmacokinetic parameters that will inform future dosing strategies.

This combination therapy approach reflects a broader trend in DKD research toward using multiple agents simultaneously to address several pathogenic pathways. The rationale for combining an ANGPTL3 antibody with a small-interfering RNA targeting the same protein is to achieve more robust inhibition through complementary mechanisms of action. As phase 2 trials progress, researchers are examining whether combination approaches yield additive or synergistic benefits in reducing albuminuria and preserving kidney function compared with monotherapy approaches.

SGLT2 Inhibitors: Expanded Evaluation Across Diverse Patient Populations

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have emerged as foundational agents in DKD treatment, with multiple ongoing trials extending their evaluation across increasingly diverse patient populations. The TRUTH-DKD trial is a multicenter, randomized, open-label, controlled trial comparing the SGLT2 inhibitor tofogliflozin directly against metformin in 120 participants with type 2 diabetes and DKD 2. Participants in this trial must have an estimated glomerular filtration rate (eGFR) of at least 30 mL/min/1.73 m2 and urinary albumin-to-creatinine ratio (UACR) between 30 and 2000 mg/gCr, with stratification by baseline UACR, eGFR, and age. This trial directly addresses the evidence gap regarding metformin's protective effects on renal outcomes, as metformin remains a first-line agent despite limited contemporary evidence supporting specific renal benefits.

Additional SGLT2 inhibitor trials include the RESOLUTION study evaluating luseogliflozin in patients with type 2 diabetes and moderate to severe renal dysfunction (eGFR 15-45 mL/min/1.73 m2) 3. This trial examined whether luseogliflozin could slow renal function decline over 104 weeks. Results indicated that while initial eGFR decline occurred at 2 to 12 weeks (likely a hemodynamic adaptation), chronic eGFR slope trends appeared less negative in the luseogliflozin group, suggesting potential benefit in more advanced kidney disease stages. The SUGARNSALT trial is also recruiting participants with type 1 diabetes and moderate to severe DKD to evaluate sotagliflozin, extending SGLT2 inhibitor investigation to type 1 diabetes populations, a historically underrepresented group in DKD clinical research.

Mineralocorticoid Receptor Antagonists and Combination Strategies

Mineralocorticoid receptor antagonists (MRAs) represent another major therapeutic class under investigation in DKD trials. Finerenone, a nonsteroidal MRA, has become a central focus of multiple concurrent studies. The CONFIDENCE trial demonstrated that simultaneous initiation of finerenone and empagliflozin (an SGLT2 inhibitor) produced additive benefits in reducing UACR compared with either monotherapy 4. Among 800 participants, UACR reduction at day 180 with combination therapy was 51% in those using a baseline GLP-1 receptor agonist and 56% in those not using one, compared with approximately 34-37% reduction with finerenone alone and 33-36% with empagliflozin alone. Importantly, hyperkalemia incidence rates with combination therapy were 9.0% to 9.5%, indicating that clinically relevant electrolyte complications remained manageable with appropriate monitoring.

The SAFE-K trial (Safety of Finerenone Versus Alternate-Day Spironolactone in Elevated Potassium) is specifically designed to address the concern of hyperkalemia risk in high-risk populations 5. This randomized trial will compare finerenone with alternate-day spironolactone dosing in patients with heart failure and diabetic kidney disease who have elevated risk for hyperkalemia. The trial recognizes that while MRAs provide renal and cardiovascular benefits, their use is frequently limited by elevated serum potassium levels. A separate Phase IIb trial (BaxDuo-Baltic) is evaluating baxdrostat, a direct aldosterone synthase inhibitor, in combination with dapagliflozin in chronic kidney disease patients with hypertension, further expanding the MRA class evaluation in DKD-relevant populations.

Emerging Therapeutic Classes and Novel Mechanisms

Beyond established drug classes, novel investigational agents targeting diverse pathogenic mechanisms are advancing through clinical development. The TRIDENT 2.0 observational study is recruiting participants to examine how SGLT2 inhibitors affect kidney tissue biology at the molecular and cellular level, comparing SGLT2 inhibitor users with non-users through kidney tissue analysis 6. This mechanistic approach provides deeper insights into how these agents exert their renoprotective effects. The R3R01 trial (Kidney ABC) is investigating an ABCA1 inducer as a novel intervention targeting abnormal lipid metabolism in DKD, representing an alternative mechanistic approach focused on cholesterol efflux biology.

Autologous cell therapy represents another innovative therapeutic direction. A randomized Phase 2 clinical trial of rilparencel, an autologous cell therapy composed of cells obtained by kidney biopsy, demonstrated that bilateral kidney injections were associated with a 78% improvement in annual eGFR decline 7. In the rilparencel study, preinjection annual eGFR slope was -5.84 mL/min per 1.73 m2 per year, which improved to -1.27 mL/min per 1.73 m2 per year after injections. No serious adverse events related to rilparencel therapy were reported, suggesting procedural feasibility and acceptable safety. Additional emerging therapies under investigation include Chinese herbal medicine formulas as adjunctive therapy (DKD-1 formula), montelukast (a leukotriene antagonist as part of the MIRACLE-T2D trial), and endothelin receptor antagonists including atrasentan.

GLP-1 Receptor Agonists and Glucosuric Agent Combinations

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have demonstrated significant promise in protecting kidney function beyond their glucose-lowering effects. The FLOW trial prespecified analysis examined semaglutide's kidney outcomes by baseline mineralocorticoid receptor antagonist use, finding that semaglutide reduced the risk of the primary kidney outcome (persistent eGFR reduction of 50% or greater, kidney failure, or death from kidney or cardiovascular causes) by 49% in MRA users and 21% in non-MRA users versus placebo 8. The SOUL trial examined oral semaglutide in 9,650 participants with type 2 diabetes, atherosclerotic cardiovascular disease, and/or chronic kidney disease. While the five-point kidney outcome (50% eGFR decline, persistent eGFR less than 15, kidney replacement therapy initiation, or kidney/cardiovascular death) did not reach statistical significance, mean annual eGFR decline was less with oral semaglutide (-1.67 mL/min per 1.73 m2) than placebo (-2.06 mL/min per 1.73 m2), with a treatment difference of 0.40 mL/min per 1.73 m2 9. This modest but consistent eGFR preservation across diverse patient subgroups supports ongoing investigation of GLP-1 RAs in DKD populations.

Real-World Effectiveness Studies and Implementation Research

Complementing mechanistic trials, pragmatic and observational studies are examining how DKD therapies perform in routine clinical practice. The FIRST-2.0 China study is an observational research initiative tracking 5,000 patients starting finerenone treatment, collecting data from electronic health records to understand medication performance in everyday clinical practice 10. Eligible participants include adults aged 18 and older with type 2 diabetes and CKD stages 2-4 who have not previously received finerenone. The study requires at least 12 months of continuous medical records and evidence of kidney damage through UACR of at least 30 mg/g or eGFR of 15-60 mL/min. Key study goals include understanding baseline patient characteristics, tracking kidney function changes and potassium levels, monitoring hyperkalemia incidence, and analyzing treatment patterns including dose adjustments and medication persistence.

The RAPID-CKM (RAndomized EHR-based Prescribing to Improve Disease-modifying Therapies for Cardio-Kidney-Metabolic Care) trial represents implementation science research designed to improve real-world therapy initiation. This pragmatic randomized trial evaluates whether an Epic electronic health record-based clinician notification increases initiation of guideline-directed cardio-kidney-metabolic therapies in adults with type 2 diabetes and confirmed albuminuria. The notification strategy identifies confirmed albuminuria and potential eligibility for evidence-based therapies using existing electronic health record data, recognizing that substantial treatment gaps persist despite contemporary guideline recommendations. These implementation trials address the substantial divide between clinical trial efficacy and real-world effectiveness in managing DKD populations.

Trial Design Features, Eligibility Criteria, and Practical Considerations

Modern DKD clinical trials employ increasingly standardized eligibility criteria and design features that reflect evolving understanding of disease pathogenesis and therapeutic windows. Most trials require participants to have type 2 diabetes with HbA1c between 6.5% and 10%, eGFR between 20 and 90 mL/min per 1.73 m2 (depending on trial phase and specific intervention), and evidence of albuminuria (UACR generally 30 mg/g or greater) 1. Trials frequently exclude participants with eGFR below 15-30 mL/min per 1.73 m2, end-stage renal disease on dialysis, or serum potassium greater than 4.8-5.5 mmol/L, reflecting safety considerations for experimental agents and concern for hyperkalemia with MRA-based therapies. Recent myocardial infarction, stroke, or cardiovascular hospitalization within 30-90 days typically results in exclusion, as does symptomatic heart failure above NYHA class I in some trials. Stable background therapy with angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers is required in most trials, though some recent studies specifically examine combinations with novel agents added on top of existing RAAS blockade. Participants are generally required to be between 18 and 75-80 years of age and capable of providing informed consent. These standardized criteria facilitate participant recruitment and ensure that trial populations represent individuals with active DKD suitable for experimental intervention evaluation.