Direct acting antivirals have completely changed the landscape of the treatment of chronic hepatitis C. The management of the few patients who relapse to direct acting antivirals requires a careful analysis of the chances to achieve therapeutic success with a second antiviral course. In this context, the usefulness of viral resistances testing, able to detect resistance-associated substitutions in the viral sequence, is at present a matter of debate. Areas covered: The role of resistance associated substitutions is examined through the evaluation of the data from clinical trials that have assessed the impact of viral resistances on the treatment outcome. Special attention has been paid on the data from re-treatment studies. Expert commentary: The treatment failure in chronic hepatitis C is still a possible event. Therefore, additional real-world clinical data on relapse rates and on the relapse management are welcome to definitely address the clinical guidelines. At present, the testing of viral resistances is an exquisite tool for the choice of the re-treatment schedule. In the near future, widespread use of the most recently registered direct acting antivirals with high barrier to resistance will probably weaken the need of resistance testing as a support in clinical decisions.
Keywords: Chronic hepatitis C; direct acting antivirals; resistance-associated substitutions; treatment failure; viral resistance.