31%, p = 0.003). As for IL28B SNPs, there were no significant differences in viral response until week 12 in SMV, while IL28B gene variation was identified as a significant predictive factor for SVR in TVR by multiple logistic-regression analysis (OR = 12.0, p = 0.029). Drug adherence of TVR click here (OR = 16.1, p<0.0001) and PEG-IFN (OR = 11.8, p<0.0001) were also associated with SVR in TVR treatment, and it was suggested that more than 60% of TVR and 80% of PEG-IFN were needed for achieving SVR for difficult-to-treat patients such as null responders of prior treatment or non rapid viral responders.

Adherence of RBV became significant in SMV treatment, because adherence of SMV were 100% in 95% of the participants. Before treatment, RAVs against NS3 and NS5A inhibitors were detected in 3% and 17% of the patients by direct sequencing, and 45% and 87% by deep sequencing, respectively. SVR rates in TVR were not different between patients with and without RAVs of NS3 (79% and 91%, respectively, p = 0.362), and those of NS5A (86% and 76%, p = 0.443), and viral clearance rates of patients with RAVs of NS3 and/or NS5A were equal. However, in patients unresponsive to IFN who

had NS5A RAVs before treatment, failure of TVR or SMV treatment resulted in development of multi-drug PLX-4720 molecular weight resistant variants. Conclusion: IFN-based DAAs regimens achieve high SVR rates regardless of presence of RAVs at baseline as much as good adherence has maintained. In contrast, failure of the treatments in patients with NS5A RAVs at baseline MCE lead to a risk for development of multi-drug resistant variant, which may hamper next generation IFN-free regimens with DAAs. Disclosures: Yasuhiro Asahina – Grant/Research Support: Chugai Pharceutical Co. Ltd., Toray Industries, Inc., Dainippon-Sumitomo Pharma Co. Ltd, Merck Sharp and Dohme, Bristol-Myers Squibb The following people

have nothing to disclose: Mina Nakagawa, Miki Taniguchi, Takako Watanabe, Yuki Nishimura-Sakurai, Yasuhiro Itsui, Seishin Azuma, Sei Kakinuma, Yujiro Tanaka, Mamoru Watanabe Introduction: Safe and effective treatment for HCV-infected patients with severe renal impairment is currently unavailable and represents an area of unmet medical need. As compared to those with normal renal function, the AUC0-inf of SOF is 2.7-fold higher in patients with severe renal impairment, and the AUC0-inf of GS-331007, the renally excreted major SOF metabolite, is 5.5-fold higher. This study investigates the safety, efficacy and PK of SOF+RBV in HCV-infected patients with severe renal impairment. Methods: In an open-label study, 10 patients with chronic HCV GT1 or 3 with creatinine clearance (CrCl) less than 30mL/min as calculated by the Cockcroft-Gault equation, not on dialysis, are being treated with SOF 200mg + RBV 200mg daily for 24 wks.