One-Year Outcomes After Belatacept Conversion in Adolescent Kidney Transplant Recipients

Belatacept (CTLA4-Ig) has shown efficacy in adult kidney transplantation (KT) recipients (improved graft and patient survival and reduced de novo donor-specific antibody [DSA]) compared with calcineurin inhibitors (CNIs). Its long-term benefits and monthly i.v. administration have raised interest in pediatric use, particularly in adolescents, who face an increased risk of graft loss because of nonadherence. However, data on belatacept use in pediatrics are limited. Our objective was to report the 1-year outcomes of all adolescents (N = 45) who underwent CNIs-to-belatacept conversion between 2018 and 2021, in a multicenter retrospective study conducted in the USA and France.

Indications included long-term CNI avoidance because of toxicity (e.g., histological changes, posttransplant diabetes, and tremors), suboptimal creatinine, or to improve adherence. One-year outcomes were compared with a propensity-matched cohort of adolescents remaining on CNIs.

The median age was 17 years. Rejection occurred in 11 of 45 patients (24%) at a median of 10 months postconversion (7 T-cell-mediated rejections, 3 antibody-mediated rejections, 1 mixed). Belatacept was discontinued in 3 of 11 patients whereas CNIs were added in 2 of 11. Rejection and de novo DSA rates did not differ between patients on belatacept and patients on CNIs. At the individual level, estimated glomerular filtration rate (eGFR) in patients on belatacept without rejection increased significantly (median + 19%), compared with rejectors (-3%, P = 0.03) and patients on CNI (nonrejectors: -11%, P = 0.0006; or rejectors: -14%, P = 0.012). No apparent increase in infectious complications was observed.

Although rejection rates in pediatric patients on belatacept seemed higher than in adult cohorts, they were not significantly different from adolescent patients on CNI, underscoring the challenges related to nonadherence in this population. Tailored immunosuppression strategies, including belatacept, may offer benefits for selected adolescents, but further studies are necessary to define optimal patient selection.