University of California, San Diego School of Medicine, San Diego, CA, USA. firstname.lastname@example.org.
Entecavir is a potent nucleoside analog for treating chronic hepatitis B (CHB). Quantitative HBsAg levels (qHBsAg) are predictive of response to interferon alfa in CHB treatment; however the clinical utility of qHBsAg in nucleos(t)ide analog-based CHB therapy is not fully characterized. This study assessed changes in qHBsAg in patients treated with entecavir in the phase III study ETV-022.
This retrospective post-hoc analysis included nucleos(t)ide-naïve, HBeAg-positive patients receiving entecavir (0.5 mg daily) in ETV-022 who had samples available for qHBsAg analysis through Week 48. qHBsAg, HBV DNA, and ALT were assessed for the overall patient cohort, for cohorts with or without HBeAg loss or HBsAg loss by Week 48, and by HBV genotype.
Ninety five patients from ETV-022 had available samples for qHBsAg analysis through Week 48. In all cohorts, 48 weeks of entecavir therapy resulted in effective HBV DNA suppression. In the overall cohort, qHBsAg declined by -0.92 log10 IU/mL through Week 48. The decline in qHBsAg was more pronounced in patients with subsequent HBeAg loss or HBsAg loss, and in patients infected with HBV genotype D or A. On-treatment qHBsAg changes did not correlate with changes in HBV DNA; no on-treatment or baseline factor was found to be predictive of HBeAg loss or HBsAg loss.
Through 48 weeks of entecavir therapy, qHBsAg declined predominantly in those patients who achieved seroclearance of HBeAg or HBsAg. However, unlike with interferon alfa-based therapy, early qHBsAg decline was not predictive of serologic response at Year 1 of entecavir treatment.