Critical appraisal of belatacept for prophylaxis of rejection in kidney transplant patients

Belatacept (LEA29Y) is an intravenous biologic for long-term maintenance immunosuppressive therapy in renal transplant recipients. It is currently being reviewed by the United States Food and Drug Administration (FDA) as a prophylactic therapy against acute cellular rejection (ACR) in de novo renal transplant recipients. To provide an in-depth review of the pharmacology, clinical efficacy, safety, and applications of belatacept, a MEDLINE database search was performed for all English-language articles evaluating the pharmacology and efficacy of belatacept, as well as abstracts from recent scientific meetings. Belatacept is a potent inhibitor of B7 binding to CD28, a potent T-cell co-stimulatory signal. The B7 ligands are found on the surface of antigen-presenting cells, specifically B7-1 (CD80) and B7-2 (CD86). CD80 and CD86 are essential ligands for CD28, a critical component of costimulation in the three-signal transplant model of T-cell activation. Belatacept has proven noninferiority compared with calcineurin-inhibitor (CNI)-based regimens in the incidence of patient and allograft survival. However, the incidence and severity of ACR has been shown to be increased in patients receiving belatacept therapy. Although rates of ACR are increased in patients receiving belata- cept, an overall improvement in allograft function has been described with average improve- ments in glomerular filtration rates of up to 12-15 mL/min higher than CNI-based regimens. The side-effect profile of belatacept has been shown to be similar or improved compared with CNI therapy; however, the risk of malignancy, specifically post-transplant lymphoproliferative disorder is notably higher. Because of the marked increase in the risk of malignancy and ACR, approval of belatacept by the FDA will rely on more robust data from long-term follow-up of currently available data.