PURPOSE: Anti-programmed cell death receptor-1 (PD-1) antibodies have 
demonstrated antitumor activity in many cancer entities. Hepatic adverse events 
(AEs) are one of its major side effects, but the overall risks have not been 
systematically evaluated. Thus, we conducted this meta-analysis to investigate 
the overall incidence and risk of developing hepatic AEs in cancer patients 
treated with PD-1 inhibitors.
METHODS: PubMed, Embase, and oncology conference proceedings were searched for 
relevant studies. Eligible studies were randomized controlled trials of cancer 
patients treated with PD-1 inhibitors with adequate data on hepatic AEs.
RESULTS: A total of nine randomized controlled trials with a variety of solid 
tumors were eligible for the meta-analysis. The use of PD-1 inhibitors 
significantly increased the risk of developing all-grade hepatic AEs but not for 
high-grade hepatic AEs in comparison with chemotherapy or everolimus control. 
Additionally, the risk of all-grade and high-grade hepatic AEs with a 
nivolumab/ipilimumab combination was substantially higher than ipilimumab. No 
significant differences in the risk of all-grade and high-grade hepatic AEs were 
found between PD-1 inhibitors monotherapy and ipilimumab.
CONCLUSION: While the use of PD-1 inhibitors is associated with an increased 
risk of developing hepatic AEs in cancer patients, this is primarily for lower 
grade events.