Simplified Immunosuppression with Belatacept and Once-Daily Azathioprine and Prednisone in Pediatric Kidney Transplantation

Background: Belatacept, a co-stimulation blocker, is increasingly utilized in calcineurin inhibitor (CNI) sparing regimens. However, data regarding its use in pediatric kidney transplant recipients in conjunction with once-daily azathioprine and steroids are limited. Methods: We retrospectively reviewed data on five pediatric kidney transplant recipients who were transitioned from CNI to belatacept for maintenance immunosuppression between July 2021 and March 2025. All patients received thymoglobulin induction at the time of transplant. Data are summarized as median with interquartile range and proportions. Results: The median age at transplant was 6.9 years (IQR 2.4–7.6). Median time from transplant to belatacept conversion was 8.7 years (IQR 7.8–11.7), and median age at conversion was 15.4 years (IQR 14.5–15.6). Three recipients (60%) were white, four (80%) were female, four (80%) received deceased donor organs, and two (40%) had a history of prior transplant. All had congenital anomalies of the kidney and urinary tract. Four recipients were EBV seropositive at transplant, while one seroconverted after transplant but before belatacept initiation. Three recipients converted due to CNI toxicity and two for non-adherence. Before conversion, four were on tacrolimus, one on cyclosporine, three on azathioprine, and two on mycophenolate; all received prednisone. Post-conversion, all but one were on azathioprine and prednisone. eGFR stabilized in all five (Figure). Two had DSA (present pre-conversion), with no rise in titers after conversion(Figure). One recipient discontinued belatacept after 11 months due to infusion-related dizziness and post-infusion somnolence; no other adverse effects were observed. Conclusion: Belatacept in conjunction with azathioprine and prednisone is a safe and viable option for pediatric kidney transplant recipients with CNI toxicity or non-adherence.