Costimulation blockade: the next generation

Calcineurin inhibitors (CNIs) are central to immunosuppression in kidney transplantation (KT), improving short-term outcomes but falling short in enhancing long-term outcomes due to cardiovascular, metabolic, and renal complications. Belatacept, an FDA-approved costimulation blocker, offers a less toxic alternative to CNIs but is limited by its intravenous administration and reduced efficacy in high-immunological-risk patients.

Emerging therapies target more specific pathways to improve efficacy and accessibility. Abatacept, a first-generation cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) immunoglobulin, has shown favorable outcomes in small studies. VEL-101 and Lulizumab selectively block CD28 while preserving CTLA-4 signaling, showing promise in early trials. In the CD40/CD40L pathway, results have been mixed. Iscalimab (CD40 antibody) was inferior to tacrolimus in Phase 2 trials, and Bleselumab (CD40 antibody) showed variable rejection rates despite being noninferior to tacrolimus. CD40L-targeting agents such as TNX-1500, Tegoprubart, and Dazodalibep have demonstrated promising efficacy and safety in rejection prophylaxis.

The focus in transplantation is shifting toward safer, long-term therapies with greater accessibility. Investigational agents with subcutaneous delivery methods could overcome logistical challenges, improve adherence, and redefine posttransplant care. These advancements in costimulation blockade may enhance long-term graft survival and transform the management of KT recipients.