Role of Underlying Liver Pathology in the Development of Immune-Related Hepatitis: A Case-Control Study

Immune-related hepatitis (irH) is a serious immune-related adverse event (IRAE) that may result in morbidity, immune checkpoint inhibitor (ICI) therapy interruption and, rarely, mortality. The impact of underlying liver pathology, including liver metastasis, on the incidence of irH remains poorly understood.

We hypothesized that the presence of underlying liver pathology increased the risk of irH in patients with cancer treated with ICI.

We conducted a retrospective case-control study of irH in patients with cancer receiving first ICI treatment from 2016-2020. Provider documented cases of ≥ grade 2 irH were identified and control matched in a 2:1 ratio based on age, sex, time of ICI initiation, and follow-up time. Conditional logistic regression was used to estimate the relationship between irH and liver metastasis at ICI initiation.

Ninety-seven cases of irH were identified, 29% of which had liver metastases at time of ICI initiation. Thirty-eight percent of patients developed grade 2, 47% grade 3, and 14% grade 4 irH. When adjusted for covariates/confounders, the presence of liver metastasis was associated with increased odds of irH (aOR 2.79 95% CI 1.37-5.66, p = 0.005). The presence of liver metastases did not correlate with irH grade or rate of irH recurrence after ICI rechallenge.

Presence of liver metastases increased the odds of irH in patients with first-time ICI therapy. Limitations include the retrospective nature, moderate sample size, possible selection bias and confounding. Our findings are hypothesis-generating and warrant external validation as well as tissue and circulating biomarker exploration.