RT Journal Article T1 Prevalence of NS5A resistance associated substitutions in patients with hepatitis C virus genotypes 1a and 3: Impact on current therapeutic strategies. A1 Grandal, Marta A1 Pernas, Berta A1 Tabernilla, Andres A1 Mariño, Ana A1 Alvarez, Hortensia A1 Valcarce, Nieves A1 Mena, Alvaro A1 Castro-Iglesias, Angeles A1 Perez, Ana B A1 Delgado, Manuel A1 Poveda, Eva K1 HCV-infection K1 NS5A K1 RASs K1 genotype 1a K1 genotype 3 AB The presence of resistance-associated substitutions (RASs) at NS5A region might compromise the efficacy of Direct Acting Antiviral agents (DAAs). HCV resistance at NS5A region is mainly focused on patients with hepatitis C virus (HCV) genotypes 1a (G1a) and 3 (G3) with other factors of poor treatment response (ie cirrhosis, prior treatment-exposure, or HCV-RNA >800 000 IU/mL). Herein, we evaluated in a cohort of HCV G1a and G3 infected patients the prevalence of RASs at domain I NS5A using population-based sequencing and the impact of RASs on the optimization of current therapeutic strategies. The RASs considered as clinically relevant were: M28A/G/T, Q30D/E/H/G/K/L/R, L31M/V/F, H58D, and Y93C/H/N/S for G1a and Y93H for G3. A total of 232 patients naïve to NS5A inhibitors were included (166 G1a, 66 G3). The overall prevalence of NS5A RASs for G1a and G3 patients was low (5.5%) or null, respectively. A high proportion of patients harbored, at least, one factor of poor response (78.9% for G1a, and 75.8% for G3). Overall, the rates of patients harboring NS5A RASs in combination with any of the other factors were low and the vast majority of patients (G1a> 94% and G3 100%) could be treated with standard treatments of 12 weeks without ribavirin. In conclusion, testing NS5A RASs in specific HCV-infected populations (ie G1a & G3, cirrhosis, prior treatment experienced, HCV-RNA >800 000 IU/mL) might be useful to optimize current NS5A-based therapies avoiding ribavirin-related toxicities, and shortening treatment duration in the majority of patients. PB John Wiley & Sons, Inc. YR 2018 FD 2018-02-18 LK http://hdl.handle.net/10668/12111 UL http://hdl.handle.net/10668/12111 LA en NO Grandal M, Pernas B, Tabernilla A, Mariño A, Álvarez H, Valcarce N, et al . Prevalence of NS5A resistance associated substitutions in patients with hepatitis C virus genotypes 1a and 3: Impact on current therapeutic strategies. J Med Virol. 2018 Jun;90(6):1094-1098. DS RISalud RD Apr 5, 2025