2% and 99.6% of the patients. Patients with cirrhosis who relapsed after 12 weeks of treatment had relatively high viral loads at baseline and a significantly

higher HCV viral load at treatment weeks 1, 2 and 4 than those with SVR. In patients with cirrhosis with HCV RNA ≥ LLOQ at treatment week 1 or 2, SVR rates were significantly higher after 24 than after 12 treatment weeks (p=0.027 and p=0.025, respectively). However, after 12 weeks of therapy, the ability to predict failure in cirrhotic patients based on the presence of detectable virus at week 1 or 2 was low (NPV = 8.2% and 17.6%, respectively). Conclusion: The number of patients with quantifiable HCV RNA early in treatment is low across the LDV/SOF Aloxistatin cell line phase 3 program. Even in patients with quantifiable HCV RNA levels, SVR is high. Nevertheless, HCV RNA quantification at early time points during treatment with LDV/SOF ± RBV for GT 1 HCV infection may be considered for further optimization of treatment duration in some subpopulations. Disclosures: Tania M. Welzel – Advisory Committees or Review Panels: Novartis, Janssen, Gilead, Abbvie, Boehringer-Ingelheim+ Patrick Marcellin – Consulting: Roche,

Gilead, BMS, Vertex, Novartis, Janssen, MSD, Abbvie, Alios BioPharma, Idenix, Akron; Grant/Research Support: Roche, Gilead, BMS, Novartis, Janssen, MSD, Alios BioPharma; Speaking and Teaching: Roche, Gilead, BMS, Vertex, Novartis, Janssen, MSD, Boehringer, Pfizer, Abbvie Nezam Copanlisib mouse H. Afdhal – Consulting: Merck, Vertex, Idenix, GlaxoSmithKline,

Spring-bank, Gilead, Pharmasett, Abbott; Grant/Research Support: Merck, Vertex, Ide-nix, GlaxoSmithKline, Springbank, Gilead, Pharmasett, Abbott Kris V. Kowdley – Advisory Committees or Review Panels: AbbVie, Gilead, Merck, Novartis, Trio Health, Boeringer Ingelheim, Ikaria, Janssen; Grant/Research Support: AbbVie, Beckman, Boeringer Ingelheim, BMS, Gilead Sciences, Ikaria, Janssen, Merck, Mochida, Vertex Luisa M. Stamm – Employment: Gilead Sciences Yanni Zhu – Employment: Gilead Sciences, Inc.; Stock Shareholder: Gilead Sciences, Inc. Phillip S. Pang – Employment: Gilead Sciences John G. McHutchison – Employment: Gilead Sciences; Idoxuridine Stock Shareholder: Gilead Sciences Stefan Zeuzem – Consulting: Abbvie, Boehringer Ingelheim GmbH, Bristol-Myers Squibb Co., Gilead, Novartis Pharmaceuticals, Merck & Co., Idenix, Janssen, Roche Pharma AG, Vertex Pharmaceuticals The following people have nothing to disclose: Eva Herrmann Purpose: Non-cirrhotic, treatment-naïve HCV GT1a adults in the phase 3 PEARL-IV trial achieved intent-to-treat SVR12 rates of 97.0% and 90.2%, respectively, with the 3D regimen (ABT-450 [identified by AbbVie and Enanta and boosted with ritonavir, ABT-450/r], ombitasvir, and dasabuvir), with or without ribavirin (RBV). We investigated the efficacy of 3D±RBV in patients grouped by baseline factors.