Characterization of NS5A and NS5B resistance-associated substitutions from genotype 1 HCV infected patients in a Portuguese cohort

• Autor(a) principal: Brandão, Ruben Alexandre Ribeiro
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/37051
• topic: Hepatitis C virus; Direct-acting antivirals; Resistance-associated substitutions; NS5A; NS5B; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Hepatitis C virus (HCV) is considered to be the leading cause of hepatocellular carcinoma (HCC). During the last years, several highly efficacy regimens of direct-acting antivirals (DAAs) with excellent rates of success became available. However, therapeutic failure may occur in up to 10% of treated individuals. Our aim was to study the profile of NS5 coding region RASs in DAA-naive genotype 1 HCV infected patients, as well as to ascertain an association between treatment failure and the presence of baseline NS5 RASs. A comparison between LiPA and Sanger sequencing genotyping methods was also assessed. Plasma RNA from 81 DAA-naïve GT1 HCV infected patients was extracted, followed by an in-house nested RT-PCR of the NS5 coding region. PCR products were purified, leading to Sanger population sequencing on the 3130xl ABI Genetic Analyzer. Sequences were aligned using ChromasPro v1.7.6, and analyzed online in hcv.geno2pheno.org. NS5A RASs were present in 28,4% (23/81) of all GT1 infected patients. The most commonly detected NS5A RAS was Y93C/H with a prevalence of 9,9% (8/81) in all GT1 infected patients. NS5B RASs showed a prevalence of 14,8% (12/81) in all GT1 infected patients, and were only detected in GT1b, being mainly represented by C316N accounting for 40% (10/25). The combined Q30H+Y93H NS5A RASs, were detected at baseline in one HIV/HCV GT1a co-infected patient who later failed a treatment with sofosbuvir/ledipasvir (SOF/LDV) for 12 weeks. An isolated Y93H mutation was also detected at baseline in a relapsing GT1b mono-infected patient. Overall 38,3% (31/81) of all GT1 HCV infected patients presented NS5 RASs at baseline, in which 58% (18/31) were co-infected with HIV/HCV. The obtained data supports the usefulness of resistance testing prior to treatment initiation, as a statistical significant association was found between treatment failure and the baseline presence of specific NS5 RASs, namely Y93C/H (p = 0.04).