Neoadjuvant programmed cell death 1 inhibitor before liver transplantation for HCC is not associated with increased graft loss

Immune checkpoint inhibitors (ICIs) may lead to rejection and even graft loss of solid organ transplant recipients, making them not widely used in transplant patients. There is insufficient clinical experience in using ICIs as a bridging or downstaging therapy before transplantation. We performed a retrospective review of patients receiving programmed cell death 1 inhibitor (PD1) before liver transplantation for HCC in our center and analyzed the data of these patients with the purpose of investigating the safety and feasibility of preoperative PD1 inhibitor among liver transplant recipients and exploring the preoperative correlation ICIs and the postoperative risk of rejection and immune-related graft loss. A total of 16 patients enrolled in this study. Acute rejection occurred in 9 patients, with an incidence of 56.3%. The median time of rejection was 7 days after surgery. The median FK506 concentration at the time of rejection was 7.1 μg/L. All rejection reactions were reversed after adjusting the immunosuppression regimen. The interval between the last PD1 inhibitor and transplantation in the rejection group was shorter than that in the nonrejection group, and there was a statistical difference [21.0 (15.5-27.5) days vs. 60.0 (34.0-167.0) days, p=0.01]. In conclusion, PD1 inhibitor is a safe and feasible method for bridging or downstaging treatment before liver transplantation. Although preoperative PD1 inhibitor may increase the incidence of postoperative rejection, it is not associated with increased immune-related graft loss and patient death.