Background Early conversion from calcineurin inhibitor to mammalian target of rapamycin inhibitor is one of the immunosuppressive strategies that have been investigated to mitigate long-term CNi associated adverse events. This study aims to evaluate the conversion from tacrolimus to sirolimus in de novo kidney transplant recipients.

This multicenter, open-label study, planned to enroll 297 patients initially treated with tacrolimus, enteric-coated mycophenolate sodium (1440 mg/day, orally) and prednisone. The primary objective is to show superior glomerular filtration rate in the SRL group at 24 months after transplantation.

Inclusion Criteria:

• patients older than 18 years,
• recipients of first kidney transplant from brain dead deceased or living related non-HLA identical donors not older than 65 years,
• patients had to receive an ABO compatible organ with a CDC negative crossmatch and a peak panel reactive antibody lower that 30%,
• all patients agreed to use contraceptive methods during the study and up to 3 months after study drug discontinuation.

Exclusion Criteria:

• patients with chronic kidney diseases due to focal and segmental glomerulosclerosis and membranoproliferative glomerulonephritis,
• patients with active infection or positive for hepatitis B or C or human immunodeficiency viruses,
• patients with previous history of malignancy,
• patients with significant hematological or metabolic laboratorial abnormalities.