The Pharmacovigilance Risk Assessment Committee (PRAC) of the European Medicines Agency (EMA) has confirmed that patients being treated with certain direct-acting antiviral (DAA) drugs for hepatitis C virus (HCV) infection are at risk of experiencing a reactivation of hepatitis B virus (HBV).

As a result of this review, the PRAC recommended that all patients should be screened for prior or current HBV infection before initiating DAA therapy. The committee also advises health professionals to monitor patients using blood tests for HBV flare-ups or reactivation during treatment, as well as at the post-treatment follow-up period.

DAA medications such as Daklinza, Exviera, Harvoni, Olysio, Sovaldi and Viekirax, which are marketed in the European Union, prevent HCV from multiplying. In most cases, they can cure HCV infection. (A list of DAAs available in the U.S. can be accessed at this U.S. Food and Drug Administration link).

Cases of hepatitis B reactivation have been reported in patients treated with DAA medications and who were infected with hepatitis B and C viruses. According to a press release from the EMA, this may be the result of the rapid treatment-induced reduction in HCV, and the lack of activity that DAA drugs have against HBV.

PRAC recommends a boxed warning be added in the prescribing information for DAA drugs. The committee also revised the available data on liver cancer (hepatocellular carcinoma) in patients treated with DAAs, and determined that more studies are needed before conclusions can be drawn. The review process will continue upon data availability.

PRAC will send this recommendations to the Committee for Medicinal Products for Human Use (CHMP), which is expected to adopt the agency’s opinion. The final stage of the review procedure is the adoption of a final decision by the European Commission (EC), which will be valid for all E.U. Member States.

EMA started the review of DAA medications in March. Japan’s Pharmaceuticals and Medical Devices Agency (PMDA) also announced that a review of this type of medications in underway in that country. In October, the U.S. Food and Drug Administration (FDA) also released a warning about serious risks for patients infected with HBV and who are being treated with certain DAAs against HCV.