Maintenance Immunosuppression in Kidney Transplantation: A Review of the Current Status and Future Directions

Kidney transplantation remains the gold standard for managing end-stage kidney disease, providing superior survival and quality-of-life outcomes compared to dialysis. Despite the ongoing gap between organ availability and demand, it is inevitable that kidney transplantation will continue to grow. This is owed to broader organ sharing, increased comfort of transplant programs with marginal kidney utilization, and the expansion of paired exchange among living donor kidneys. The evolution of kidney transplantation could not have been possible without the availability of effective immunosuppressive regimens that prevent rejection and maintain graft function. Mycophenolic acid and calcineurin inhibitors continue to serve as the foundation of modern maintenance immunosuppression. While these agents have markedly reduced acute rejection rates, their long-term efficacy in graft survival remains suboptimal. Alternative immunosuppressive therapies, including belatacept and mammalian target of rapamycin inhibitors, have demonstrated potential benefits. However, concerns regarding an increased risk of rejection have limited their widespread adoption as primary treatment options. In addition to ongoing efforts to refine steroid- and calcineurin inhibitor-sparing strategies, the identification of practical and quantifiable biomarkers for predicting long-term graft survival remains a critical objective. This review evaluates contemporary immunosuppressive protocols, highlights existing challenges, and explores future directions for optimizing long-term transplant outcomes.