We aimed to evaluate the long-term assessment of fibrosis regression by serial liver stiffness

(LS) measurement using Fibroscan® during antiviral treatment, and to investigate the predictors for persistent fibrosis regression. Methods: Between March 2006 and April 2010, we prospectively enrolled chronic hepatitis B (CHB) patients who underwent LS measurement and liver biopsy before starting nucleot(s)ide analogues and showed histologically moderate to severe inflammation or significant fibrosis, with a high viral loads [HBV DNA>2,000 IU/mL]. After starting antiviral treatment, annual LS measurement for 5 years or further during antiviral treatment was performed. Significant fibrosis LBH589 datasheet regression was defined as a > 30% drop of LS value from the baseline, and persistent fibrosis regression was defined as significant fibrosis regression identified in three consecutive measurements performed in Year 3, 4, and 5. Results: A total of 120 patients received antiviral treatment and annual LS measurement for 5 years. At baseline, the median LS value was 12.1 dB/m, and 89 (74.2%)

patients showed F4 fibrosis (cirrhosis) on liver biopsy. During 5 years of antiviral treatment, the GSI-IX median LS value significantly decreased as years go by (10.3 dB/m at Year 1; 9.0 dB/m at Year 2; 8.6 dB/m at Year 3; 7.3 dB/m at Year 4; and 6.9 Dolichyl-phosphate-mannose-protein mannosyltransferase dB/m at Year 5; P<0.001). Significant fibrosis regression was identified in 30.0%, 48.3%, 54.2%, 65.0%, and 60.8% patients at Year 1,2,3,4, and 5, respectively, and persistent fibrosis regression was present in 56 (46.7%) patients. Multivariate analyses identified a higher baseline LS value as a predictor for persistent fibrosis regression (P<0.001; hazard ratio, 1.186; 95% confidence interval,

1.091-1.290). Conclusion: In patients with CHB receiving long-term antiviral treatment, the annual LS measurement revealed that fibrosis regression slows down but continues during treatment. Baseline fibrotic burden represented as LS value is a single independent predictor for persistent fibrosis progression. Disclosures: The following people have nothing to disclose: Young Eun Chon, Myung Sung Min, Kyu Sik Jung, Kwang-Hyub Han, Seung Up Kim, Do Young Kim, Sang Hoon Ahn, Jun Yong Park HSP47 is a unique gene target in the collagen-mediated folding pathway leading to the formation of liver fibrosis. Strategy of using siRNA targeting HSP47 for liver fibrosis treatment was first reported by Sato et al. (2008). Since this prototype formulation is not applicable for clinical use, proprietary lipid nanoparticle formulation, ND-L02-s0201, were developed to encapsulate modified HSP47 siRNA incorporating vitamin A-derivative targeting components.