Background and aims: Reports of moderate to severe liver injury associated with tocilizumab, an interleukin-6 (IL-6) receptor antagonist, have been reported in the post-marketing setting. This case series aims to characterize cases of tocilizumab-associated clinically significant hepatic injury.
Methods: We analysed cases of severe acute liver injury associated with tocilizumab reported in the FDA Adverse Event Reporting System and the medical literature.
Results: We identified 12 cases in which tocilizumab was a suspected primary cause of liver injury and eight cases in which serious sequelae of underlying or coincident viral hepatitis were temporally associated with its use. Using the Drug-Induced Liver Injury Network (DILIN) severity scale, five of 12 cases were Grade 5 (two liver transplants, three deaths), one was Grade 4 (liver failure) and six were Grade 3 (serious events with elevated bilirubin). Two cases reported liver atrophy with low hepatocellular expression of Ki-67, a marker of cellular proliferation. Among the eight cases of tocilizumab-associated viral hepatitis exacerbation, three were scored as DILIN severity Grade 5 (one liver transplant, two deaths), one was Grade 4 (liver failure), and four were Grade 3. The reported viral hepatitis events were hepatitis B virus (HBV) reactivation (n = 3), hepatitis C virus (HCV) flare (n = 1), cytomegalovirus (CMV)-induced liver failure (n = 1), Epstein-Barr virus hepatitis (n = 1), acute hepatitis E (HEV, n = 1) and HEV-induced macrophage activation syndrome (n = 1).
Conclusion: Tocilizumab may be a primary cause of severe liver injury, as well as exacerbate underlying viral hepatitis. The disruption by tocilizumab of IL-6-mediated immune protection and hepatocyte regeneration may aggravate clinical outcomes in some cases.
Keywords: HBV reactivation; HCV flare; IL-6; drug-induced liver injury; tocilizumab.
Published 2020. This article is a U.S. Government work and is in the public domain in the USA.