A Comparison of Entecavir and Lamivudine for the Prophylaxis of Hepatitis B Virus Reactivation in Solid Tumor Patients Undergoing Systemic Cytotoxic Chemotherapy

BACKGROUND Nucleos(t)ide analogues reduce the incidence of hepatitis B virus (HBV) reactivation in cancer patients undergoing systemic cytotoxic chemotherapy but the experience of solid tumors remains limited. Aims. The aim of this study was to compare the efficacy of entecavir and lamivudine in the prophylaxis of HBV reactivation in solid tumor patients undergoing systemic cytotoxic chemotherapy. METHODS HBsAg seropositive patients undergoing systemic cytotoxic chemotherapy for solid tumors with prophylactic entecavir and lamivudine between January 2006 and June 2013 were retrospectively investigated. The incidence of HBV reactivation and outcome of the patients were analyzed. The risk factors of HBV reactivation were examined. RESULTS A total of 213 patients (entecavir group, 70 patients; lamivudine group, 143 patients) were evaluated. Less incidence of HBV reactivation was noticed in entecavir group than in lamivudine group (0% vs. 7.0%, P = 0.02). No HBV reactivation was noticed in the patients with a baseline HBV DNA level < 2000 IU/mL. A baseline HBV DNA level ≥ 2000 IU/mL, HBeAg, and lamivudine were significantly associated with HBV reactivation. Subgroup analysis of the patients with a baseline HBV DNA level ≥ 2000 IU/mL found that lamivudine was significantly associated with HBV reactivation. Most of the reactivation events were properly managed by using tenofovir disoproxil fumarate. The incidence of hepatitis during chemotherapy and disruption of chemotherapy was similar between patients using entecavir and lamivudine with a baseline HBV DNA level ≥ or < 2000 IU/mL. CONCLUSIONS A baseline HBV DNA level ≥ 2000 IU/mL, HBeAg, and lamivudine were the risk factors of HBV reactivation during systemic cytotoxic chemotherapy in solid tumor patients. Entecavir was superior to lamivudine in terms of less incidence of reactivation in the patients with a baseline HBV DNA level ≥ 2000 IU/mL. Both agents were equally efficacious in the patients with HBV DNA levels < 2000 IU/mL.