A 96-week randomized trial of switching to entecavir in patients who achieved virological suppression on lamivudine therapy.

BACKGROUND AND AIM: There are limited data assessing whether patients who achieved virological suppression on lamivudine but remain hepatitis B "e" antigen-positive should be switched to a more potent antiviral with a high genetic barrier to resistance or continue with lamivudine. We compared the safety and efficacy of switching with entecavir versus continuing lamivudine.

METHODS

This was a Phase IV, randomized, open-label, prospective study in a tertiary care setting. Seventy-three chronic hepatitis B patients who achieved virological suppression on lamivudine (serum hepatitis B virus DNA < 60 International Unit (IU)/mL) were enrolled. Entecavir or lamivudine were administered orally for up to 96 weeks. Virologic and serologic responses were measured throughout the study.

RESULTS

A significantly higher proportion of patients in the entecavir group achieved hepatitis B virus DNA < 60 IU/mL at Weeks 48 (100% [38/38] vs 62.8% [22/35]; P < 0.001) and 96 (97.4% [37/38] vs 57.1% [20/35]; P<0.001). A greater number of patients had virologic breakthrough (Week 96 cumulative incidence 42.9% vs 2.6%; P<0.001) and genotypic lamivudine resistance (28.6% [10/35] vs 0% [0/38]; P<0.001) in the lamivudine group. No serious adverse events or laboratory abnormalities were reported.

CONCLUSIONS

Even after achieving virological suppression on lamivudine therapy, the risk of emergent lamivudine resistance increases over time. Switching to entecavir resulted in a maintained virologic response and superior serologic responses versus continued lamivudine therapy. This study supports a rationale for switching to entecavir in chronic hepatitis B patients with virological suppression on lamivudine.