Harrington PR, et al. - Authors aimed at describing methods and key findings from independent regulatory analyses investigating the impact of baseline nonstructural (NS) 3 Q80K and NS5A resistance-associated substitutions (RASs) on the efficacy of current United States Food and Drug Administration (FDA)-approved regimens for patients with hepatitis C virus (HCV) genotype (GT) 1 or GT3 infection. Findings supported that in selected patient groups, baseline HCV RASs can reduce the efficacy of certain direct-acting antiviral (DAA)-based regimens. However, their impact can be minimized with the use of an intensified treatment regimen, such as a longer treatment duration and/or addition of ribavirin.