Impact of everolimus: update on immunosuppressive therapy strategies and patient outcomes after renal transplantation

Abstract

Everolimus is an immunosuppressive agent used for the prophylaxis of acute rejection after kidney transplantation. Everolimus inhibits the activity of the serine/threonine kinase mammalian target of rapamycin (mTOR), a key enzyme that controls cell growth and metabolism, producing cell cycle arrest from the G1 to S phase. As a consequence, everolimus has antiproliferative and antineoplastic effects. Everolimus is a drug with a narrow therapeutic index. The pharmacokinetics of everolimus indicates a need for twice-daily dosing. Intra- and interindividual variability and drug-drug interactions suggest the need for therapeutic drug monitoring to maximize the efficacy/toxicity ratio. The good correlation between exposure (area under the concentration-time curve) and trough concentration indicates that monitoring of everolimus trough concentrations is an adequate strategy after kidney transplantation. Everoli- mus is indicated for low- to moderate-risk de novo kidney transplant candidates. There are no conclusive studies thus far indicating that everolimus can be used in high-risk patients, such as sensitized patients, retransplants, and African Americans. In de novo kidney transplant recipi- ents, the recommended initial dose of everolimus is 0.75 mg twice daily, adjusted to maintain blood trough concentrations of 3-8 ng/mL, in combination with progressive reduction in blood trough cyclosporine concentrations to 25-50 ng/mL. In combination with reduced trough blood tacrolimus concentrations of 4-7 ng/mL the recommended initial dose of everolimus is 1.5 mg twice daily, adjusted to maintain trough blood concentrations of 3-8 ng/mL. Everolimus can also be used as a conversion strategy, mainly to preserve renal function and to manage patients with malignancy. There is no definition of the ideal strategy for conversion, ie, abrupt or sequential, initial dose of everolimus, or target therapeutic trough blood concentrations. Intensive monitor- ing is recommended after conversion, especially for acute rejection and proteinuria. Because mTOR is ubiquitous and central to many intracellular processes, an array of adverse reactions may occur, including delayed tissue regeneration, proteinuria, dyslipidemia, diabetes, myelosup- pression, infertility, ovarian cysts, and mouth ulcers. Because long-term benefits are the goal of any immunosuppressive strategy, further investigations aiming to understand, prevent, and manage everolimus-related adverse reactions are necessary to mitigate the risks and improve tolerability, allowing maximization of all the benefits of this drug.