Low-Dose Calcineurin Inhibitor Regimen Combined With Mammalian Target of Rapamycin Inhibitors Preserves Kidney Functions in Renal Transplant Recipients Without Allograft Nephropathy

Abstract Objective The present study was designed to investigate the effect of low-dose calcineurin inhibitor (CNI) tacrolimus combined with a mammalian target of rapamycin (mTOR) inhibitor on renal function in transplant recipients without allograft nephropathy. Patients and methods Twelve patients including seven men (58.3%) of overall mean age of 34.8 ± 14.1 years underwent renal transplantation and were switched to a new second-line treatment of low-dose CNI combined with an mTOR inhibitor, either sirolimus or everolimus. Results The underlying cause of renal failure was not clear in half of the cases; for the others it was chronic glomerulonephritis, diabetic nephropathy, polycystic kidney disease, or hypovolemia. After 6 months of the new therapy, there was a significant increase in calculated creatinine clearance levels compared to baseline (75.5 ± 21.9 vs 89.6 ± 19.1 mL/min; P < .001), but no significant change in serum creatinine (1.3 ± 0.4 vs 1.2 ± 0.3 mg/dL) or urinary protein excretion (187.5 ± 142.0 vs 394.0 ± 326.4 mg/g). For almost all patients, proteinuria remained stable, but in two patients, it developed but responded to enalapril treatment. Dose decrement was required for four patients with hyperlipidemia (50%); one patient experienced new-onset hyperlipidemia that responded to treatment. One patient developed a urinary tract infection that responded to antibiotic treatment. None of the patients developed an acute rejection episode. Conclusion Low-dose CNI combined with an mTOR inhibitor, as a replacement for mycophenolate mofetil or enteric-coated mycophenolate sodium, seemed to prevent renal dysfunction for at least 6 months among renal transplant patients without allograft nephropathy.