RESULTS: Analysis of the entire group indicated that 76% achieved SVR. In 63 patients treated with TVR, who showed non response to prior treatment, a higher proportion of patients undetected PI-resistant variants Temozolomide in vitro at the baseline (54%) achieved SVR than that of patients detected resistant variants at the baseline (0%). In patients treated with TVR, multivariate analysis identified PEG-IFN dose (<1.3 μg/ kg), IL28B rs8099917 (genotype non TT), TVR-resistant variants of aa54 at the baseline (Detection), response to prior treatment (Non response), and leukocyte count (<5,000/mm3) as significant

pretreatment factors of detection of TVR-resistant variants at the re-elevation of viral load. 12 patients (6 patients of TVR, and 6 of SMV), who did not achieve SVR, were

tested for resistant variants over time by ultra-deep sequencing. 21 of 30 resistant variants (70%), detected at re-elevation of viral load, were de novo resistant variants. 19 of 21 de novo resistant variants (90%) become undetectable over time. Furthermore, 6 patients (4 patients of TVR, and 2 of SMV), who did not achieve SVR by the first course of triple therapy, received the Bioactive Compound Library solubility dmso second course of the triple therapy. 4 of 6 patients (67%) achieved SVR by the second course, despite the persistence of very high frequency variants or the past history of the emergence of variants by ultra-deep sequencing. CONCLUSIONS: This study indicated that PI-resistant variants at the re-elevation of viral load could be predicted by the combination of host, viral, and treatment factors. Resistant variants at the baseline might partly affect treatment efficacy, especially non response to prior treatment. The emergence of PI-resistant variants after the start of treatment could not be predicted at baseline,

and the majority of de novo resistant variants become undetectable over time. Disclosures: Norio Akuta – Patent Held/Filed: medchemexpress SRL. Inc. Hiromitsu Kumada – Speaking and Teaching: Bristol-Myers Squibb,Pharma International, MSD, Dainippon Sumitomo, Tanabe Mitsubishi, Ajinomoto The following people have nothing to disclose: Fumitaka Suzuki, Yushi Sorin, Taito Fukushima, Yusuke Kawamura, Hitomi Sezaki, Yoshiyuki Suzuki, Tetsuya Hosaka, Masahiro Kobayashi, Satoshi Saitoh, Mariko Kobayashi, Yasuji Arase, Kenji Ikeda Background: Sofosbuvir was approved for the use in Germany January 2014. Recommendation in Germany (BNG/DGVS) voted for the triple therapy with PEG-IFN, Ribavirin(Riba) and Sofosbuvir(SOF) with a duration of 12 weeks. Dual therapy with SOF and Riba should be limited to special cases.