Entecavir as a first-line treatment for hepatitis B virus reactivation following polychemotherapy for chronic lymphocytic leukemia and invasive ductal carcinoma: a report of two cases and review of the literature

Objective Hepatitis B reactivation has been reported in chronic carriers of hepatitis B [hepatitis B surface antigen (HBsAg)] or in patients with prior hepatitis B virus (HBV) infection who are HBsAg-negative and have antibodies against hepatitis B core antigen (anti-HBc) with or without antibodies to HBsAg (anti-HBs). Lamivudine has been the first and commonly used nucleoside analog to inhibit HBV replication; however, prolonged therapy has been associated with an increased risk for drug-resistant mutations and mortality rates. Entecavir, a deoxyguanosine analog, offers several advantages over lamivudine for the treatment of HBV reactivation following chemotherapy while exhibiting more potent antiviral activity and a lower resistance rate