Entecavir is one of the therapeutic options currently available for the management of chronic
hepatitis B. In this study, we aimed to analyse the virological response and
antiviral resistance mutations in
chronic hepatitis B subjects experiencing
entecavir therapy from the Indian subcontinent. A total of 45
chronic hepatitis B subjects were studied at baseline and were followed up on
entecavir treatment. Among these subjects, 25 (56%) were
HBeAg-positive at baseline. Virological response was measured by hepatitis B virus (HBV)
DNA levels. HBV
reverse transcriptase (rt) domains were sequenced for the identification of resistance mutations. Three-Dimensional (3D) model of
HBV polymerase/rt
protein, docking and molecular dynamics simulation (MDS) studies were performed for characterization of
antiviral resistance mutations. At the median
treatment duration of 6 (IQR 6-11) months, 38 (84%) showed virological response. Subjects who showed anti-HBe response demonstrated significant association with virological response (p=0.034). On sequence analysis, none of the subjects were identified with signature
entecavir resistance mutations. However, one subject was exclusively detected with rtV173L mutation. Molecular modeling, docking and MDS studies revealed that the rtV173L mutation cannot confer resistance to
entecavir independently. Our findings also showed that the prevailing HBV genotypes, subgenotypes and
HBsAg subtypes in this population does not influence treatment outcome to
entecavir therapy. In conclusion,
entecavir is a potent
drug in terms of
viral DNA suppression. In addition, none of the subjects developed
antiviral resistance mutations to
entecavir. Therefore
entecavir is a suitable
drug of choice in the management of chronic HBV.