Re-treatment of HCV Following DAA Failure

HCV infection is treated with oral drugs, termed as 'direct-acting anti-viral agents' (DAAs). In India, four DAAs are available (sofosbuvir \[SOF\], daclatasvir \[DCV\], ledipasvir \[LDV\] and velpatasvir \[VEL\]). Globally, DAA based regimens have obtained excellent rates of cure. Cure of HCV infection is defined as undetectable HCV RNA 12 weeks after stopping drugs, also referred to as sustained virological response at week 12 (SVR12). Using these DAA based treatment regimens, a small number (up to 5%) of people fail to achieve SVR12 and HCV RNA reappear after a few weeks of stopping the drugs (virological relapse). Data on management of virological relapse are extremely limited, especially in genotype 3, and no guidelines exist regarding re-treatment options for such group. Hence, we plan to re-treat such people using what appear to be the best combination treatment in each situation and to review our experience over time. Participants with chronic HCV infection who relapsed following standard DAA-based treatment regimen will be invited to participate. We propose to re-treat them with the anti-HCV drug combination which appears to be the most suited to his/her clinical profile, based on the current empiric knowledge - the choice of drugs will be based on HCV genotype, the previous treatment regimen and the presence/absence of liver cirrhosis, etc. During anti-HCV treatment, participants will be given expected standard of care and HCV RNA will be tested at 4-week intervals starting from week 4 and till RNA becomes undetectable, and then at the end of treatment and 12 weeks after the treatment was stopped - as is the usual practice during such treatment. Relevant clinical, laboratory and treatment details will be recorded in a pre-defined data collection form. Treatment outcome will be categorized as success (SVR12), treatment failure (any detectable HCV RNA at the end of 24 weeks treatment duration) or relapse (HCV RNA negative at the end of treatment, but posi