ABSTRACT
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 (SOF)/daclatasvir (DCV) or velpatasvir (VEL)±ribavirin (RBV) (N = 91/15) and glecaprevir (G)/pibrentasvir (P) (N = 9). Moreover, 14.8% of patients were treated with suboptimal regimens for GT3: 3D ± RBV (Paritaprevir/r + Ombitasvir+Dasabuvir, N = 15), SOF + Simeprevir (SIM) (N = 1) or SOF/Ledipasvir (LDV) ± RBV (N = 4). RAS prevalence was 15.8% in DAA-naïve patients. At failure, 81.5% patients showed at least one RAS: 11/25 (44.0%) in NS3, 109/135 (80.7%) in NS5A, 7/111 (6.3%) in NS5B SOF-failures. In NS5A-failures, Y93H RAS was the most prevalent (68.5% vs 5.1% DAA-naïve, P < .001) followed by A30K (12.7% vs 2.8% in DAA-naïve, P < .001). Analysing baseline samples, a higher prevalence of NS5A-RASs was observed before treatment in DAA-failures (5/13, 38.5%) vs DAA-naïves (61/393, 15.5%, P = .04). Regarding 228 DAA-naïve patients with an available outcome, 93.9% achieved a SVR. Interestingly, patients with baseline Y93H and/or A30K had SVR rate of 72.2% vs 95.7% for patients without NS5A-RASs (P = .002). CONCLUSIONS: In this real-life GT3 cohort, the majority of failures harboured resistant variants carrying NS5A-RASs, the most frequent being Y93H. The presence of natural NS5A-RASs before treatment was associated with failure. Further analyses are needed to confirm this observation, particularly for the new current regimens.
Subject(s)
Hepacivirus , Hepatitis C, Chronic , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Drug Resistance, Viral/genetics , Drug Therapy, Combination , Female , Genotype , Hepacivirus/genetics , Hepatitis C, Chronic/drug therapy , Hepatitis C, Chronic/epidemiology , Humans , Italy/epidemiology , Male , Phylogeny , Sofosbuvir/therapeutic use , Sustained Virologic Response , Viral Nonstructural Proteins/geneticsABSTRACT
BACKGROUND: Pretreatment evaluation of HCV-infected patients is a complex interplay between multiple clinical and viral parameters, leading to a tailored approach that may bring real-life sustained virological response (SVR) rates close to 98%-99%. OBJECTIVES: As proof-of-concept, we evaluated the efficacy of all-oral direct-acting antiviral (DAA) regimens in patients whose personalization included pre-therapy evaluation of natural resistance-associated substitutions (RASs), in addition to international guideline recommendations. METHODS: One hundred and thirty-one patients who started a first-line all-oral DAA regimen between April 2015 and December 2016 were tested for baseline NS3 and NS5A RASs by Sanger sequencing. SVR12 was defined as HCV-RNA undetectability 12 weeks after treatment discontinuation. RESULTS: Compatibly with a real-life context, 74.0% (97 of 131) of patients presented ≥2 pretreatment risk factors for failure to achieve SVR12 (infection by GT-1a/GT-3a; cirrhosis; previous treatment experience; HCV-RNA ≥800â¯000 IU/mL) and 33.6% had ≥3 risk factors. Natural RASs were frequently detected (32.1% prevalence), with substantial prevalence of NS5A RASs (15.3%), mostly represented by Y93H in GT-1b (3 of 36, 8.3%) and GT-3a (3 of 25, 12.0%) and F28C in GT-2c (2 of 11, 18.2%). Overall, personalized treatment led to 100% SVR12, even in those patients for whom treatment strategy was either strengthened (by ribavirin inclusion and/or duration increase) or simplified (by ribavirin exclusion and/or duration reduction), thanks to baseline RAS evaluation. CONCLUSIONS: Even with newer DAA regimens, an integrated interpretation of clinical and virological pretreatment parameters, including natural RASs, may play a relevant role in bringing SVR rates close to the highest achievable. Treatment tailoring can be foreseen in 'hard-to-treat' patients, but also in 'easy' patients with favourable indicators, whereby a simplification/shortening of recommended regimens can be indicated.