Morphology of immune-mediated hepatitis: A comparison between immune checkpoint inhibitor therapy and combined immune checkpoint inhibitor/anti-angiogenic therapy

Background: The combination of immune checkpoint inhibitors (ICIs) with anti-angiogenic drugs has shown promising anticancer effects. However, ICIs can trigger immune-mediated hepatitis (IMH). We aimed to clarify whether the combined use of anti-angiogenic drugs and ICIs would increase the severity of IMH. Methods: One hundred IMH patients (ICI monotherapy vs. ICI plus anti-angiogenic therapy 30 vs. 70) were retrospectively enrolled. Clinicopathological parameters were compared between the two groups. Results: IMH mainly showed variable degrees of panlobular hepatitis (84 %), while some cases presented mixed cholangio-hepatitic (14 %) or cholangitic (2 %) pattern. The incidence of moderate-severe injury was not significantly different between the two groups (combination vs. monotherapy 38.6 % vs. 20.0 %, p = 0.109). Specifically, the rates of marked lobular injury and portal inflammation were higher in the combination group than in the monotherapy cohort (p < 0.005), while the frequencies of interface hepatitis, bile duct injury, histiocytosis aggregates, and endothelialitis were comparable between the two groups (p > 0.05). Compared to mild IMH cases, severe IMH cases showed higher immunostaining expression levels of PD-L1 (60.7 % vs. 19.4 %, p < 0.0001). Treatments and outcomes of IMH were not significantly different between the two groups (p > 0.05). Conclusions: Compared to ICI monotherapy, the administration of anti-angiogenic drugs in combination with ICIs was not associated with increased hepatotoxicity.