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  Presented at the 22nd Conference of the Asian Pacific Association for the Study of the Liver (APASL)
Taipei, Taiwan
February 16-19, 2012
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Low Baseline Hepatitis B Surface Antigen (HBsAg) Levels and HBV Genotypes B/C are Associated with Persistently Low HBsAg in HBeAg+ Patients Treated with Tenofovir Disoproxil Fumarate (TDF)
  Reported by Jules Levin
22nd Conference of the Asian Pacific Association for the Study of the Liver (APASL)
February 16-19, 2012 Taipei, Taiwan
S Fung1, E Gane2, IM Jacobson3, P Dinh4, R Ebrahimi4, LJ Yee4, EB Martins4, P Charuworn4, K Kitrinos4, G Dusheiko5, H Trinh6, S Gordon7, R Flisiak8, EJ Heathcote1 and P Marcellin9
1University of Toronto, Toronto, ON, Canada; 2Auckland City Hospital, Auckland, New Zealand; 3Weill Medical College of Cornell University, New York, NY, USA; 4Gilead Sciences, Foster City, CA, USA; 5Royal Free Hospital, London, UK; 6San Jose Gastroenterology, San Jose, CA, USA; 7Henry Ford Medical Center, Detroit, MI, USA; 8Medical University of Bialystok, Bialystok, Poland; 9Hopital Beaujon, University of Paris, Clichy, France


· HBsAg loss has been studied and is associated with improved prognosis1-6 - HBsAg loss in 11% of patients in pivotal TDF study GS-US-174-0103 over 5 years2
- We have analyzed characteristics of those who have had HBsAg loss compared to those who have not lost HBsAg
[See Marcellin et al. Poster PP09-042]3
· However, it is still not known why some individuals achieve significant HBsAg declines in the absence of HBsAg loss (persistently low HBsAg) · Other individuals maintain persistently high levels of HBsAg despite treatment
- It is unclear what factors differentiate the patients who achieve persistently low HBsAg from those with persistently high HBsAg
· To evaluate in HBeAg+ patients whether pre-treatment characteristics are associated with persistently low HBsAg in the absence of HBsAg loss
· Data analyzed from TDF study GS-US-174-01037
- HBeAg-positive patients
- 266 patients enrolled
· Patients received TDF or ADV for 48 weeks, followed by TDF for another 192 weeks (Figure 1)
· The present analyses are based on data through year 4


· Quantitative HBsAg levels
- Abbott Architect assay (Abbott Park, Illinois, USA)
· Definitions based on an "area under the curve" approach (Figure 2) - Low HBsAg
· HBsAg < 2,000 IU/mL for at least 70% of the time over 192 weeks of therapy
- High HBsAg
· HBsAg ≥ 10,000 IU/mL for at least 70% of the time over 192 weeks of therapy
- Definition allows for fluctuation and variability in HBsAg levels


*Individuals who met the high HBsAg and low HBsAg levels maintained these levels for ≥ 70% of the time over 192 weeks. · Univariable associations:
- Odds Ratios (ORs), p-values and 95% C.I.s calculated
· Multivariable associations
- Forward selection logistic regression
- Variable entry criteria set at α=0.10
- Standard statistic measurements calculated
· Odds Ratios (ORs)
· p-value
· 95% Confidence Interval (95% C.I.)