Entecavir therapy for lamivudine-refractory chronic hepatitis B: Improved virologic, biochemical, and serology outcomes through 96 weeks

In hepatitis B e antigen (HBeAg)-positive chronic hepatitis B patients who were refractory to current lamivudine therapy, switching to entecavir was superior to continued lamivudine at week 48 for histologic improvement, viral load reduction by polymerase chain reaction and alanine aminotransferase normalization. We assessed the efficacy, safety, and resistance profile of entecavir through 96 weeks of treatment. A total of 286 patients were randomized and treated with entecavir 1 mg (n = 141) or continued lamivudine 100 mg; (n = 145). At week 52, 77 entecavir-treated patients who had a protocol-defined virologic response (HBV branched DNA [bDNA] < 0.7 MEq/mL but HBeAg-positive) continued blinded therapy for up to 96 weeks. Patients were assessed for efficacy, safety, and emerging resistance. Cumulative proportions of all treated patients who achieved confirmed efficacy endpoints were also analyzed. Between week 48 and the end of dosing, the proportions of patients with HBV DNA < 300 copies/mL by polymerase chain reaction increased from 21% to 40%, and alanine aminotransferase normalization (<= 1 x upper limit of normal) increased from 65% to 81%. In the second year, HBeAg seroconversion was achieved by 10% of patients. Of the 77 patients in the second year treatment cohort, entecavir resistance emerged in six patients, and seven experienced virologic breakthrough (five with genotypic resistance acquired before year 2). The safety profile of entecavir in the second year of therapy was consistent with that reported during year 1. Conclusion: Through 96 weeks of treatment, 1 mg entecavir resulted in continued clinical benefit in lamivudine-refractory HBeAg-positive chronic hepatitis B patients with a safety profile comparable to lamivudine.