Introduction: We conducted this study to characterize the incidence, clinical features, treatment, and outcomes of immune checkpoint inhibitor (ICI) hepatotoxicity.
Methods: Patients who received ICIs (with either single-agent or combination regimens) from January 1, 2010, to March 31, 2018, were identified. Hepatotoxicity was defined as alanine aminotransferase (ALT) >5 times the upper limit of normal (ULN), in the absence of an alternate cause, and categorized as grade 3 (ALT 5-20× ULN) or grade 4 (ALT >20× ULN), according to Common Terminology Criteria for Adverse Events 4.03.
Results: Among 5,762 patients, 100 (2%) developed hepatotoxicity, occurring in a higher proportion of recipients of combination therapy (9.2%) compared with monotherapy (up to 1.7%, P < 0.001). ICIs were discontinued permanently in 69 and temporarily in 31 patients. Sixty-seven patients received steroids, 10 of whom (14%) had recurrent hepatotoxicity after the steroid taper. Thirty-one patients resumed ICIs after ALT improvement, 8 of whom (26%) developed recurrent hepatotoxicity. Characteristics of liver injury, response to steroids, and outcomes were similar between 38 individuals with and 62 without possible pre-existing liver disease. The severity and outcome of hepatotoxicity due to combination therapy were not significantly different from monotherapy. There were 36 deaths. Two had liver failure at the time of death, both with progression of liver metastases and grade 3 hepatotoxicity.
Discussion: Clinically significant ICI-related hepatotoxicity was uncommon but led to permanent ICI discontinuation in the majority. ICIs were restarted in a sizable proportion of patients, most of whom did not experience recurrent hepatotoxicity.