Median duration of ETC treatment was 38 months (6-66). Cumulative CVR rates in NA-naïve and experienced patients were 69% vs. 54% at 12th month and 84% vs. 68% at 24th month, 92% vs. 86% at 36th month, respectively (Fig.1, log-rank, p=0.32). 3 patients (10.3%) in NA-experienced group and 4 patients in NA-naïve group (2.2%) required a switch to tenofovir (TDF) due to sub-optimal response to ETC (p=0.061) and 1 NA-naïve patient developed ETC resistance (L180M, M204V, S202G). Multi-variate

logistic regression analysis showed that HBeAg positiv-ity (OR: 6.3, 95% CI 1.16-34.3, p=0.033) and previous LAM experience (OR: 5.8, 95% CI 1.15-29.2, p=0.033) were independent predictors for a requirement LDE225 to switch to TDF. Conclusion: ETC has a potent antiviral efficacy in patients with CHB. The antiviral efficacy of ETC is not influenced by prior treatment with NAs if LAM resistance is excluded at baseline. However, HBV-DNA kinetics should be carefully monitored in patients with HBeAg-positive CHB and previous LAM experience. Disclosures: The following people have nothing to

disclose: Bulent Baran, CB-839 purchase Ozlem Mutluay Soyer, Asli Cifcibasi Ormeci, Suut Gokturk, Sami Evirgen, Filiz Akyuz, Cetin Karaca, Kadir Demir, Fatih Besisik, Derya Onel, Mine Gulluoglu, Selim Badur, Sabahattin Kaymakoglu Background: Chronic hepatitis B (CHB) disproportionately affects Asian-Americans in the US. TDF has been demonstrated potent antiviral in clinical trials, but real-life data in Asian-Americans are lacking. We prospectively followed patients on TDF for 144 weeks and assessed outcomes. Methods: Asian-American patients with CHB from multiple community-based practices were prospectively enrolled and treated with TDF (300 mg/day) in a single arm study for 48 weeks. After week 48, patients had the option to continue TDF up to week 144, or opt out of further observation. The primary efficacy endpoint was hepatitis B virus (HBV) DNA < 29 IU/mL at week 48 Clomifene and 144. Secondary endpoints were safety and tolerability, serologic and biochemical

responses, liver fibrosis by FibroTest at week 48, and the development of drug resistant mutations. Results: Ninety patients were enrolled with baseline values in Table 1. At week 48, seventy four patients (82% overall; 70% HBeAg-positive and 100% HBeAg-negative) had HBV DNA <29 IU/mL. 12% (6/52) HBeAg+ patients achieved HBeAg loss/seroconversion. The percentage of patients with alanine aminotransferase (ALT) in the normal range increased from 26% at baseline to 66% at week 48. The percentage of patients with F0 fibrosis by FibroTest increased from 48% to 51%, and those with F4 fibrosis decreased from 4% to 1 %. At week 48, 31 /90 patients (19 HBeAg+) opted to continue on TDF with assessment at 12 week intervals up to week 144. Two patients with HBV viremia did not participate beyond week 48. At week 144, 84% (26/31) patients had HBV DNA <29 IU/mL; No viremic patient (n=5) had genotypic mutation on Sanger sequencing (2/5 TDF non-adherence); 67.