Current immunosuppressive approaches in liver transplantation

A significant increase of potent immunosuppressive agents over the last two decades has contributed to improved patient and graft survival after liver transplantation (LT). Numerous ongoing studies aim to determine the most effective immunosuppressive protocols while minimizing drug-related side effects. These protocols often combine several drugs with different mechanisms of action and toxicities allowing dosage adjustment. There is also a trend towards tailored immunosuppressive regimens according to the etiology of liver disease and comorbidities such as renal dysfunction and cardiovascular disease. The introduction of antibody induction therapies and antimetabolites resulted in an increasing number of studies with steroid minimization and calcineurin inhibitor (CNI) reduction protocols. Combined mycophenolate mofetil and minimal dose CM therapy has shown to be safe and to improve kidney function and cardiovascular risk profile in the majority of studies. Sirolimus (SRL) and everolimus constitute a new class of compounds designated as the mammalian target of rapamycin (mTOR) inhibitors, which exhibit immunosuppressive and antiproliferative effects. There are conflicting results with respect to renal improvement upon switch to mTOR inhibitor therapy with concomitant reduction/elimination of CNI. Further trials will determine whether earlier conversion to mTOR inhibitors enable prevention of CNI-related renal dysfunction. Future results from randomized controlled studies will also show whether SRL can improve recurrence-free survival in patients transplanted for hepatocellular carcinoma.