Optimizing the clinical utility of sirolimus-based immunosuppression for kidney transplantation.

While calcineurin inhibitors (CNIs) are effective for preventing acute rejection in kidney transplant recipients, long-term use may cause chronic kidney injury and is associated with increased risks of cardiovascular events, cancer, and infection-associated death. Immunosuppression strategies are needed to balance risks of acute and subclinical rejection with long-term benefits of improved kidney function. Sirolimus, an inhibitor of mammalian target of rapamycin, is used for immunosuppression in kidney transplantation. Its clinical utility has evolved, over more than 15 years, including de novo sirolimus with and without concomitant CNIs and conversion from CNI-based regimens to sirolimus. Sirolimus-containing regimens are associated with preservation of good renal function, with promising characteristics for improving long-term graft and patient survival, including antiviral and anticancer effects. Based on clinical evidence, use of low-dose sirolimus in a de novo approach with tacrolimus/steroids in the immediate posttransplantation period is appropriate. A feasible alternative is a long term, CNI-free combination with mycophenolate mofetil (following CNI-to-sirolimus conversion at 3-6 months). These strategies are appropriate for a broad range of patients with various levels of immunologic risk, including those receiving expanded criteria donor kidneys or at increased risk of delayed graft function, particular challenges in Latin America and other global regions.