Proteinuria in Renal Transplant Patients Treated With Dapagliflozin

Recent years have seen the emergence of sodium-glucose co-transporter type 2 (SGLT2) inhibitors, also known as gliflozins, which represent a real therapeutic innovation in the management of type 2 diabetes, heart failure and chronic kidney disease.

The prevalence of chronic kidney disease is rising steadily and represents a major public health challenge. Hypertension and proteinuria are two factors strongly associated with the progression of chronic kidney disease (CKD) and the high risk of cardiovascular complications. Achieving blood pressure control and reducing proteinuria is therefore a major objective in the management of chronic renal failure. Until recently, inhibitors of the renin-angiotensin-aldosterone system were the only therapeutic class known to have both anti-proteinuric and anti-hypertensive action, reducing the risk of progression to end-stage renal disease.

Several large international studies, initially investigating the efficacy of SGLT2 inhibitors as anti-diabetic therapy, reported that this new therapeutic class reduced the risk of cardiovascular complications and end-stage renal disease. This nephroprotective and cardioprotective effect was independent of the anti-diabetic effect of the drug. The nephroprotective effect is explained in particular by a decrease in proteinuria via a reduction in glomerular hyperfiltration, and a reduction in intraglomerular pressure via vasoconstriction of the afferent artery in response to the blockade of glucose and sodium reabsorption in the proximal convoluted tubule.

An international study (Dapagliflozin and Prevention of Adverse Outcomes in Chronic Kidney Disease study) was specifically designed to investigate the nephroprotective effect of dapagliflozin in both diabetic and non-diabetic proteinuric CKD patients. This study, which included 4,300 patients with glomerular filtration rate (GFR) between 25 and 75ml/min/1.73m2 and an albuminuria/creatinuria ratio between 200 and 5,000mg/g, confirmed a significant reduction in proteinuria, a lower risk of progression to end-stage CKD and a lower mortality rate in patients treated with dapagliflozin compared with those who received placebo. Following this study, Dapagliflozin was granted marketing authorization in France in October 2021 for any patient with chronic kidney disease, in patients with a GFR between 25 and 75ml/min/1.73m2 and an albuminuria/creatinuria ratio between 200 and 5000mg/g despite treatment with converting enzyme inhibitor/Angiotensin II receptor antagonists for at least 4 weeks. Renal transplantation is not a contraindication to the use of dapagliflozin, so renal transplant patients meeting these same criteria may receive dapagliflozin as nephroprotective therapy. However, few data are currently available on the evolution of proteinuria and GFR in this population.

After renal transplantation, proteinuria is also a major factor associated with impaired graft function and cardiovascular risk. However, transplant patients have specific characteristics compared with non-transplant CKD patients: by definition, they have a single functional kidney and receive immunosuppressive treatments that modify renal hemodynamics, including calcineurin inhibitors, drugs that also have a vasoconstrictive effect. In addition, a moderate increase in the risk of urinary tract infection and genital mycotic infection has been reported with the use of gliflozins, necessitating careful monitoring of the incidence of these side effects in this population.

The investigators have been progressively introducing the use of dapagliflozin as a nephroprotective treatment in transplant patients meeting marketing authorisation criteria (chronic renal failure with GFR between 25-75ml/min/1.73m2, albuminuria/creatinuria ratio 200-5000mg/g despite treatment with converting enzyme inhibitors and Angiotensin II receptor antagonists for at least 4 weeks) within the nephrology department of Montpellier University Hospital for several months. To date, more than 30 transplant patients have been treated with dapagliflozin (of whom 12 treated patients have usable data and may be included retrospectively in this study). In this recent experience, a very good safety profile was observed and no drug interactions were identified. Although a reduction in early proteinuria was observed, the follow-up of these patients is not yet long enough to carry out a preliminary analysis.

The investigators intend to conduct an observational study with the primary objective of studying the evolution of proteinuria in kidney transplant patients treated with dapagliflozin according to marketing authorization criteria. The secondary objectives of the study are to investigate other expected benefits, including effects on renal function and metabolic effects, as well as potential side-effects of this treatment in this population.