Immune checkpoint inhibitors and their impact on liver enzymes and attenuation

Background: Immune related adverse events impacting the liver are common from immune checkpoint inhibitor (ICI) therapy; however, there is little data regarding the subclinical impact of ICIs on liver inflammation. The study aims to determine whether ICI therapy affects liver attenuation and liver enzymes in melanoma patients with and without hepatic steatosis. Methods: A retrospective, cohort study was conducted of patients with advanced melanoma treated with ICI therapy who received serial PET-CT scans at the Vanderbilt University Medical Center (VUMC). Primary outcomes included: liver attenuation measured by PET-CT/non-contrast CT and liver enzymes. Hepatic steatosis was diagnosed by radiologists on clinical imaging. Results: Among 839 patients with advanced melanoma treated with ICIs, 81 had serial PET-CT scans approximately 12 months apart and long-term survival; of these 11 patients had pre-existing steatosis/steatohepatitis. Overall, ICI was not associated with significant increases in liver enzymes in all patients; modest decreases in liver enzymes were observed in patients with pre-existing steatosis/steatohepatitis. Similarly, liver attenuation did not change from baseline to post-treatment (58.44 vs 60.60 HU, + 2.17, p = 0.055). Conclusions: ICIs may not chronically affect liver enzymes or liver attenuation, a non-invasive measure of liver fat content and inflammation, in the general population or in those with pre-existing steatosis/steatohepatitis.