Resistance analysis and treatment outcomes in hepatitis C virus genotype 3-infected patients within the Italian network VIRONET-C

Aim: This study aimed to investigate the role of resistance-associated substitutions (RASs) to direct-acting-antivirals (DAAs) in HCV genotype 3 (GT3). Methods: Within the Italian VIRONET-C network, a total of 539 GT3-infected patients (417 DAA-naïve and 135 DAA-failures, of them, 13 at both baseline and failure) were analysed. Sanger sequencing of NS3/NS5A/NS5B was performed following home-made protocols. Results: The majority of patients were male (79.4%), 91.4% were injection drug users, 49.3% were cirrhotic and 13.9% were HIV co-infected. Phylogenetic analysis classified sequences as GT3a-b-g-h (98%-0.4%-0.2%-1.2%) respectively. Overall, 135 patients failed a DAA regimen: sofosbuvir (SO…