For approved compounds, combination of AL-335 with the NS3/4A protease inhibitor, learn more simeprevir, exhibited the greatest synergy with a synergy volume of 97.2 μM2%. AL-335 also exhibited synergistic interactions with the investigational HCV NS5A inhibitor, daclatasvir, (38.0 μM2%) and the investiga-tional non-nucleoside polymerase inhibitor, setrobuvir, (29.5 μM2%) whereas the interaction with ribavirin

was additive (6.8 μM2%). Conclusions: Future IFN-free therapy for CHC will require a combination of compounds with different mechanisms of action. AL-335 demonstrates an in vitro antiviral profile that suggests it may become an important component of IFN-free combination therapy. To this end, AL-335 is currently advancing towards human clinical trials for CHC. Disclosures: Kenneth Shaw – Employment: ABT-737 clinical trial Alios Biopharma Guangyi Wang – Employment: Alios Biopharma, Inc. David B. Smith – Employment: Alios BioPharma Lawrence M. Blatt – Management Position: Alios BioPharma Julian A. Symons – Employment: Alios BioPharma

The following people have nothing to disclose: Hua Tan, Natalia Dyatkina, Leo Beigelman Background: MicroRNA-122 (miR-122) is an important host factor for hepatitis C virus (HCV). Binding of miR-122 to HCV protects the HCV genome from degradation and prevents induction of an innate immune response against the virus. Miravirsen targets miR-122 and resulted in a dose dependent and prolonged decrease of HCV RNA levels. The aim of this study was to quantify plasma levels of miR-122 at baseline and during miravirsen treatment in HCV patients. Methods: We included 16

out of 36 chronic hepatitis C (genotype 1) patients who received five injections of either 3 mg/kg (n=4), selleck products 5 mg/ kg (n=4), 7 mg/kg (n=4) miravirsen or placebo (n=4) over a 4 week-period in a prior phase 2a study, from whom blood samples were collected at baseline, week 1, week 4, week 6 and week 10/12. RNA was isolated from plasma with the miRCURY RNA isolation kit (Exiqon) and cDNA was synthesized using qScript microRNA cDNA Synthesis Kit (Quanta). The expression levels of miR-122 were measured by quantitative PCR and normalized for levels of miR-93 and miR-191. Results: The median plasma level of miR-122 at baseline in patients receiving miravirsen was 4.3×10^3 compared to 2.2 ×10^3 copies/nl in placebo treated patients (p=ns). During anti-miR treatment, miR-122 levels showed an average 3.7fold reduction (log 2 copies/^l) between baseline and week 1 (p=0.04), 4.5-fold reduction at week 4 (p=0.007), 7-fold reduction at week 6 (p=0.016) and 6-fold reduction at week 10/12 (p=0.006) (Figure 1).