Global 
Deutschland Liver and Bile
Hepatology. 2025;82(5):1122-1137
Determining safe washout period for immune checkpoint inhibitors prior to liver transplantation: An international retrospective cohort study
Background and aims: Immune checkpoint inhibitors (ICIs) are increasingly used in patients with advanced HCC patients awaiting liver transplantation (LT). However, concerns about the risk of posttransplant rejection persist.
Approach and results: The authors conducted an international retrospective cohort study including 119 HCC patients who received ICIs prior to LT. They analyzed the incidence of allograft rejection, graft loss, and posttransplant recurrence with a particular focus on the washout period between the last ICI dose and LT. In this study, 24 of the 119 (20.2%) patients experienced allograft rejection with a median time to rejection of 9 days (IQR, 6–10) post-LT. A linear relationship was observed between shorter washout periods and higher rejection risk. Washout periods < 30 days (OR = 21.3, 95% CI: 5.93–103, p < 0.001) and between 30 and 50 days (OR = 9.48, 95% CI: 2.47–46.8, p = 0.002) were significantly associated with higher rejection rates in the univariate analysis compared to the washout period above 50 days. Graft loss as a result of rejection occurred in 6 patients (25%) with rejection. No factors related to grafts were associated with rejection. A longer washout period was not associated with a lower recurrence-free survival posttransplantation at 36 months (71% vs. 67%, p = 0.71).
Conclusions: These findings suggest that a washout period longer than 50 days for ICIs before LT appears to be safe with respect to rejection risk. While these results may help guide clinical decision-making, future prospective studies are essential to establish definitive guidelines.