Resistance detection and re-treatment options in hepatitis C virus-related chronic liver diseases after DAA-treatment failure

Background: Introduced in 2013–2014, the second- and third-wave directly acting antivirals (DAAs) have strongly enhanced the efficacy and tolerability of anti-HCV treatment, with a sustained virological response (SVR) in 90–95% of cases treated. The aim of this paper was to focus on the type and prevalence of viral strains with a reduced sensitivity to DAAs and on treatment choices for DAA-experienced patients. Methods: The Medline was searched for “HCV infection”, “HCV treatment”, “Directly acting antivirals”,“HCV resistance”. Results: Most patients who did not achieve an SVR have been found to be infected with HCV mutant strains with a reduced susceptibility to these drugs. These mutants occur frequently in the NS5A region, with a moderate frequency in the NS3/4A regions and rarely in the NS5B region. Treatment-induced mutants resistant to NS5A DAAs persist for years after treatment discontinuation, whereas those resistant to the NS3 DAAs have a shorter duration. Conclusions: Patients who have failed HCV treatment with DAA agents have several re-treatment options, but re-treatment selection may be intricate and resistance testing is recommended to optimize this choice. It is, therefore, important to bear in mind that the correct determination of HCV genotype and subtype and the identification of RASs are essential elements for choosing the optimal re-treatment. It is supposed that it is useful to give readers some other suggestions regarding therapeutic reprocessing.