Objective  To evaluate the safety of programmed cell death protein 1 (PD-1) inhibitor in the treatment of primary liver cancer (liver cancer) before liver transplantation.

  Methods  Clinical data of 7 recipients given with PD-1 inhibitor before liver transplantation for liver cancer were retrospectively analyzed. The incidence of immune-related adverse event (irAE) and clinical prognosis of the recipients were summarized. The safety of PD-1 inhibitor in recipients prior to liver transplantation for liver cancer was evaluated.

  Results  Seven recipients were treated with PD-1 inhibitor with 1-20 courses before liver transplantation for liver cancer. The time interval from drug withdrawal to liver transplantation was 6-120 d. Five recipients suffered from irAE of different degrees, including fatigue in 3 cases, fever in 2 cases, alopecia in 2 cases, rash in 1 case, nausea in 1 case and myocarditis in 1 case, respectively. A majority of these irAE were classified as grade Ⅰ-Ⅱ. One recipient died from grade Ⅴ irAE (fatal myocarditis). One recipient developed rejection at postoperative 7 d, which were mitigated after glucocorticoid pulse therapy combined with increased dosage of tacrolimus.

  Conclusions  PD-1 inhibitor can be applied in preoperative treatment before liver transplantation for liver cancer. Nevertheless, the incidence of irAE and postoperative rejection should be intimately monitored.