APAP-CYS Protein Adduct Concentrations in Patients With Liver-Directed Therapy Intended to Treat Hepatic Tumors

Acetaminophen-cysteine protein adducts (APAP-CYS) are formed when acetaminophen is oxidized by CYP 2E-1. When hepatocytes die, these proteins are released into the serum and can be detected. APAP-CYS can therefore be an experimental biomarker of acetaminophen exposure. It is possible that massive necrosis of hepatocytes that contain APAP-CYS from therapeutic doses of acetaminophen can be misinterpreted as acetaminophen overdose as the cause of liver injury. This study aims to describe serum APAP-CYS concentrations in patients taking a therapeutic dose of acetaminophen who develop a liver injury from a cause other than acetaminophen. This study will seek to enroll subjects undergoing a hepatic embolization procedure to treat a secondary liver tumor. This procedure is a reproducible model of non-acetaminophen induced hepatic injury. A small number of subjects who are otherwise eligible to participate but are unwilling to take acetaminophen will be offered participation in the observational arm of the study. They will undergo the same assessments with the exception of acetaminophen dosing. Subjects willing to take acetaminophen will be asked to take extra strength acetaminophen (4g/day) for the 3 days prior to their embolization procedure. All subjects will be asked to keep a detailed medication diary for the three days prior and up to their embolization procedure. Blood samples for the measurement of APAP-CYS concentrations and markers of liver function will be collected prior to acetaminophen dosing, prior to the embolization procedure, and at several time points after the procedure.