Hepatitis B Virus Reactivation Associated With Direct-Acting Antiviral Therapy for Chronic Hepatitis C Virus: A Review of Cases Reported to the US Food and Drug Administration Adverse Event Reporting System

Background: Direct-acting antiviral agents (DAAs) are used increasingly to treat hepatitis C virus (HCV) infection. Reports were published recently on hepatitis B virus (HBV) reactivation (HBV-R) in patients with HBV-HCV co-infection. Hepatitis B virus reactivation, defined as an abrupt increase in HBV replication in patients with inactive or resolved HBV infection, may result in clinically significant hepatitis. Objective: To assess whether HBV-R is a safety concern in patients receiving HCV DAAs. Design: Descriptive case series. Setting: U.S. Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS). Patients: 29 patients with HBV-R receiving HCV DAAs. Measurements: Clinical and laboratory data. Results: The FDA identified 29 unique reports of HBV-R in patients receiving DAAs from 22 November 2013 to 15 October 2016. Two cases resulted in death and 1 case in liver transplantation. Patients in whom HBV-R developed were heterogeneous regarding HCV genotype, DAAs received, and baseline HBV characteristics. At baseline, 9 patients had a detectable HBV viral load, 7 had positive results on hepatitis B surface antigen HBsAg) testing and had an undetectable HBV viral load, and 3 had negative results on HBsAg testing and had an undetectable HBV viral load. For the remaining 10 patients, data points were not reported or the data were uninterpretable. Despite provider knowledge of baseline HBV, HBV-R diagnosis and treatment were delayed in 7 cases and possibly 7 others. Limitations: The quality of information varied among reports. Because reporting is voluntary, HBV-R associated with DAAs likely is underreported. Conclusion: Hepatitis B virus reactivation is a newly identified safety concern in patients with HBV-HCV co-infection treated with DAAs. Patients with a history of HBV require clinical monitoring while receiving DAA therapy. Studies would help determine the risk factors for HBV-R, define monitoring frequency, and identify patients who may benefit from HBV prophylaxis and treatment. DAAs remain a safe and highly effective treatment for the management of HCV infection. Primary Funding Source: None.