Of those, there were 207 samples did not work or we were not able to achieve a HCV sequence consensus by Sanger sequencing. most frequent after Q80K. Overall, 286 samples had the Q80K polymorphism (11.1%) and 614 (23.9%) were GT1a clade I. HIV/HCV-coinfected patients had a higher frequency of Q80K and GT1a clade I than HCV-monoinfected patients (12.9% vs. 9.6% [p = 0.012] and 28.5% vs. 21.4% [p 0.001], respectively). Both the prevalence of Q80K and GT1a clade I were not uniform throughout the country (p 0.001), which ranged from 7.3%-22.2% and 15.7%-42.5%, respectively. The frequency of the Q80K polymorphism was far higher in patients infected with GT1a clade I than in patients infected with GT1a clade II (41.5% vs. 1.6%; p 0.001). Conclusions The prevalence of most resistance-associated variants in NS3 was low in patients infected with HCV GT1a in Spain, except for Q80K (11.1%), which was also notably higher in HIV/HCV-coinfected patients. The vast majority of Q80K polymorphisms were detected in GT1a clade I. Introduction Hepatitis C virus (HCV) therapy has changed rapidly CL-387785 (EKI-785) with new direct-acting antiviral drugs (DAAs), particularly for HCV genotype 1, achieving high rates of sustained virologic response [1]. However, one of the main problems with new DAAs is the presence of resistance-associated variants (RAVs), which are naturally existing polymorphisms in the HCV genome that result in less susceptibility to DAAs and can lead to virological failure Rabbit polyclonal to Ezrin to HCV treatment [2]. Thus, prior knowledge of the prevalence of RAVs could be useful to determine pre-treatment management with DAAs. HCV NS3 protease is a very attractive target for therapeutic intervention but shows a high degree of genetic variability and is able to influence HCV susceptibility to NS3 protease inhibitors (PIs) [1]. Several RAVs within NS3 protease have been described with generally a low frequency in HCV genotype 1-infected patients [3], except for the Q80K variant, which causes no loss of replicative fitness in many patients resulting in a relatively high probability of pre-existence [2]. The Q80K variant has been associated with resistance to some approved PIs (simeprevir, asunaprevir, paritaprevir) in phenotypic assays [1]. In clinical trials, presence CL-387785 (EKI-785) of the Q80K variant at baseline has only a significant effect on HCV treatment with simeprevir in combination with pegylated interferon alpha and ribavirin in patients CL-387785 (EKI-785) infected with HCV genotype 1a (GT1a), but may also facilitate the emergence of additional HCV mutations and subsequent failure to therapy [4]. Thus, screening for Q80K is recommended before treatment with simeprevir is initiated [5]. HCV GT1a strains have been described as belonging to two CL-387785 (EKI-785) distinct clades, clade I and II, which are both related to the development of antiviral resistance [6]. Interestingly, the Q80K variant is detected almost exclusively in viral isolates from patients infected with HCV GT1a, clade I [7,8]. The highest Q80K prevalence has been reported in North America where 47% of patients present this polymorphism [9]. In contrast, a lower Q80K prevalence in HCV-infected patients with GT1a has been found in European studies, varying from 5%-40% according to geographic location [10C16]. The aim of this study was to analyze the prevalence of clinically relevant RAVs within NS3 in patients infected with HCV GT1a in Spain. Materials and Methods Patients and samples We performed a cross-sectional study in chronically infected individuals with HCV GT1a from 115 hospitals distributed geographically throughout 18 out of the 19 autonomous communities of Spain between October 2014 and October 2015. The samples were sent to the National Center of Microbiology (Instituto de Salud Carlos III [ISCIII]) for the Q80K determination, together with a minimum data set (patient code, age, gender, HIV infection, hospital, and region). These data and samples were anonymized and transferred to the ISCIII National Biobank (Ref.: B.0000984). The study was conducted in accordance with the Declaration of Helsinki. The Institutional Review Board and the Research Ethic Committee of ISCIII approved the study. Initially, 2971 samples were used. Of those, there.