The Successful Use of De Novo Belatacept with Reduced Dose Tacrolimus to Mitigate the Risks of Delayed Graft Function in Kidney Transplantation

ABSTRACT

Purpose: The new kidney allocation system has caused increased organ travel times and therefore increased cold ischemia time. Furthermore, the change in the priority to larger transplant centers has caused deprioritized centers to accept higher risk extended criteria donors. These factors lead to increased risk of delayed graft function (DGF). Method(s) To mitigate these risk factors of delayed graft function we have adopted an immunosuppression regimen of de novo belatacept with reduced dose tacrolimus with trough goal level of 5. We hypothesize that the use of belatacept will allow protection against rejection while allowing the renal allogaft to recover from ischemia reperfusion injury without concomitant calcineurin toxicity or vasoconstriction. The delayed addition of low dose tacrolimus can then aid in rejection prevention in addition to belatacept. Result(s) In a cohort of 83 patients we observed one graft loss, two episodes of rejection and three deaths. Of the 130 standard dose tacrolimus with no belatacept we observed no graft losses, seven rejections and one death. Two patients were converted from tacrolimus alone therapy to belatacept plus tacrolimus therapy after the diagnosis of rejection with concomitant tacrolimus toxicity. The belatacept group had a lower rate of rejection, but a higher rate of patient death with a P value <0.001 as calculated with the Z score test. The death in the tacrolimus group was due to covid. Two of the deaths in the belatacept group were cardiovascular, one was a cerebrovascular accident possible related to skull based osteomyelitis. The graft loss in the belatacept group was related to non-compliance. Conclusion(s) Despite initial reports of increased rates of rejection;we report decreased rejection with our belatacept for DGF regimen. We believe this regimen can be a useful tool to utilize more extended criteria donor kidneys in the new kidney allocation system.