1Service d'Hépatologie and Inserm U773/CRB3, Hôpital Beaujon, University of Paris, Clichy, France. Electronic address: firstname.lastname@example.org.
2Servicio de Medicina Interna Hepatologia, Hospital General Universitari Vall d'Hebron and Ciberehd, Barcelona, Spain.
3University Hospital St. Ivan Rilsky, Sofia, Bulgaria.
4Erasmus MC University Medical Center, Rotterdam, the Netherlands.
5Medizinische Klinik I, Frankfurt, Germany.
6Gilead Sciences, Foster City, CA, USA.
7Medical University of Bialystok, Bialystok, Poland.
8Uludag Universitesi Tip Fakultesi, Bursa, Gorukle, Turkey.
9Royal Free Hospital, London, UK.
10Toronto Western Hospital, University of Toronto, Toronto, ON, Canada.
BACKGROUND & AIMS:
In a study of 266 chronic hepatitis B e antigen (HBeAg)-positive patients, 23 experienced hepatitis B surface antigen (HBsAg) loss with up to 5 years of tenofovir disoproxil fumarate (TDF) treatment. HBsAg kinetics in patients with and without HBsAg loss and predictors of HBsAg loss were evaluated.
HBsAg levels were quantified every 12 weeks. Multivariable regression analysis involving prespecified baseline characteristics and on-treatment response parameters was performed; a stepwise procedure identified independent predictors of HBsAg loss.
Among patients with HBsAg loss, 14 (61%), 1 (4%), 0, and 7 (30%) were genotypes A through D; 1 (4%) was genotype F. HBsAg loss was preceded by viral suppression (HBV DNA <29 IU/mL; n=23) and HBeAg loss (n=19). Among treated patients the strongest independent predictors of HBsAg loss were Caucasian race with genotype A/D and ⩽4 years of infection (HR=14.3, 95% confidence interval [CI] 4.7-43.4; P<0.0001) and HBsAg decline of ⩾1 log10 IU/mL at week 24 (HR=13.7, 95% CI 5.6-33.7; P<0.0001). Among TDF-treated patients, a reduction in HBsAg level of ⩾1-log10 by week 12 or 24 had a positive predictive value of 35%-45%, respectively, and a negative predictive value of 94%-97%, respectively.
HBsAg loss in HBeAg-positive patients receiving TDF involves a chronology of virologic and serologic responses; patients with HBV genotypes A or D and a rapid early decline in HBsAg are more likely to lose HBsAg.