A Head-to-head Comparison of De Novo Sirolimus or Everolimus Plus Reduced-dose Tacrolimus in Kidney Transplant Recipients: A Prospective and Randomized Trial.

Background: Mammalian target of rapamycin inhibitors (mTORi), sirolimus (SRL) and everolimus (EVR), have distinct pharmacokinetic/pharmacodynamics properties. There are no studies comparing the efficacy and safety of de novo use of SRL versus EVR in combination with reduced-dose calcineurin inhibitor.

Methods: This single-center prospective, randomized study included first kidney transplant recipients receiving a single 3 mg/kg antithymocyte globulin dose, tacrolimus, and prednisone, without cytomegalovirus (CMV) pharmacological prophylaxis. Patients were randomized into 3 groups: SRL, EVR, or mycophenolate sodium (MPS). Doses of SRL and EVR were adjusted to maintain whole blood concentrations between 4 and 8 ng/mL. The primary endpoint was the 12-mo incidence of the first CMV infection/disease.

Results: There were 266 patients (SRL, n = 86; EVR, n = 90; MPS, n = 90). The incidence of the first CMV event was lower in the mTORi versus MPS groups (10.5% versus 7.8% versus 43.3%, P  < 0.0001). There were no differences in the incidence of BK polyomavirus viremia (8.2% versus 10.1% versus 15.1%, P  = 0.360). There were no differences in survival-free from treatment failure (87.8% versus 88.8% versus 93.3%, P  = 0.421) and incidence of donor-specific antibodies. At 12 mo, there were no differences in kidney function (75 ± 23 versus 78 ± 24 versus 77 ± 24 mL/min/1.73 m 2 , P  = 0.736), proteinuria, and histology in protocol biopsies. Treatment discontinuation was higher among patients receiving SRL or EVR (18.6% versus 15.6% versus 6.7%, P  = 0.054).

Conclusions: De novo use of SRL or EVR, targeting similar therapeutic blood concentrations, shows comparable efficacy and safety. The reduced incidence of CMV infection/disease and distinct safety profile of mTORi versus mycophenolate were confirmed in this study.