The pros and the cons of mTOR inhibitors in kidney transplantation.

Sirolimus and its derivate everolimus are two immunosuppressive drugs with similar chemical structure that inhibit the proliferation of T cells by interfering with a serine-threonine kinase, called mTOR. Apart from their immunosuppressive effects, these agents may also inhibit endothelial intimal proliferation, the replication of cytomegalovirus, and the development of certain cancers. The main dose-dependent adverse events of mTOR inhibitors are hyperlipidemia, thrombocytopenia, mucositis, edema, and proteinuria. The use of mTOR inhibitors in renal transplantation may allow to reduce the doses of calcineurin inhibitors. Withdrawal of calcineurin inhibitors is also possible and may improve renal function, but some patients do not tolerate this regimen because of side effects. Further studies are needed to assess the role of mTOR inhibitors in the long-term.