No clinically significant changes from baseline in vital signs and laboratory parameters were noted. For SD, GSK175 was rapidly absorbed and had a plasma elimination half-life of 46-58 h. AUC and Cmax increased dose proportionally.

Dosing with food decreased Cmax 35% and AUC 21%. For RD, GSK175 accumulated as predicted and steady state was achieved ∼13 days. Cmax and AUC increased dose proportionally. In the ongoing POC study, GSK175 is given at doses of 10, 30, and 60mg QD for 2 days. No SAEs have been reported and no subjects have discontinued because of treatment-related AEs. Following 2 days of GSK175 mono-therapy, substantial reductions in plasma HCV RNA are seen at all doses for HCV GT1 subjects (mean±SD log10 IU/mL reductions at nadir [max. change], 10mg: -2.86±0.27, 30mg: -3.38±0.19, 60mg: -3.67±0.49). Substantial reductions were also seen for HCV GT2 and High Content Screening GT3 subjects. Prolonged antiviral effect (>7 days) following treatment cessation was seen in accordance with the protracted TV2 of GSK175. Conclusions: GSK175 appears well tolerated and showed a favorable PK profile. Subsequent evaluation of GSK175 in combination with other direct acting antivirals is warranted in CHC subjects. GSK175 PK Parameters in the FTIH Study SD=Single Dose; RD=Repeat Dose. *Mean(CV%); TMedian(CV%) Disclosures: Stephen D. Gardner

– Employment: GlaxoSmithKline, GlaxoSmithKline, GlaxoSmithKline, GlaxoSmithKline Joseph Kim – Employment: GSK Benjamin Van Hecke – Employment: GSK Maribel Rodriguez-Torres – Advisory Committees or Review Panels: Hoffman La MK-1775 datasheet Roche, Pharmasset, Bristol-Myers Squibb, Inhibitex, Vertex, Janssen R&D Ireland; Consulting: Abbott Labs, Akros, Glaxo Smith Kline, Genentech, Janssen medchemexpress R&D Ireland, Santaris, Scynexis, Theravance; Grant/Research Support: Anadys, Novartis, Merck, Vertex, Hoffman-LaRoche, Inhibitex, Bristol-Myers

Squibb, Idera, Pharmasset, Sanofi-Aventis, Merck, Abbott, Pfizer, Human Genome Sciences, Gilead, Johnson & Johnson, Zymogenetics, AKROS, Scynexis, Santaris, Boehringher, Idenix, Genentech, Beckman Coulter, Mochida Pharmaceutical, Theravance Lucinda Elko-Simms – Employment: PPD (My employer), JNJ (My husband’s employer) Vincent Lopez – Employment: GlaxoSmithKline Etienne F. Dumont – Employment: GSK Robert Hamatake – Employment: GlaxoSmithKline; Stock Shareholder: GlaxoSmithKline Martin Leivers – Employment: GSK Melanie T. Paff – Employment: GlaxoSmithKline The following people have nothing to disclose: Sharon Baptiste-Brown, Kevin Gan, Z. Joe Zhu, Zhi Hong Background/Aim: Understanding HCV kinetics in patients treated with direct-acting antiviral agents (DAAs) is limited to measuring HCV serum levels: however, most DAAs target intracellular aspects of the HCV lifecycle.