Glecaprevir
Glecaprevir is a direct acting antiviral agent and Hepatitis C virus (HCV) NS3/4A protease inhibitor that targets the the viral RNA replication. In combination with [DB13878], glecaprevir is a useful therapy for patients who experienced therapeutic failure from other NS3/4A protease inhibitors. It demonstrates a high genetic barrier against resistance mutations of the virus. In cell cultures, the emergence of amino acid substitutions at NS3 resistance-associated positions A156 or D/Q168 in HCV genotype 1a, 2a or 3a replicons led to reduced susceptibility to glecaprevir. The combinations of amino acid substitutions at NS3 position Y65H and D/Q168 also results in greater reductions in glecaprevir susceptibility, and NS3 Q80R in genotype 3a patients also leads to glecaprevir resistance.   Glecaprevir is available as an oral combination therapy with [DB13878] under the brand name Mavyret. This fixed-dose combination therapy was FDA-approved in August 2017 to treat adults with chronic hepatitis C virus (HCV) genotypes 1-6 without cirrhosis (liver disease) or with mild cirrhosis, including patients with moderate to severe kidney disease and those who are on dialysis. Mavyret is also indicated for HCV genotype 1-infected patients who have been previously treated with regimens either containing an NS5A inhibitor or an NS3/4A protease inhibitor, but not both. Hepatitis C viral infection often leads to decreased liver function and subsequent liver failure, causing a significantly negative impact on the patients' quality of life. The ultimate goal of the combination treatment is to achieve sustained virologic response (SVR) and cure the patients from the infection. In clinical trials, this combination therapy achieved SVR12 rate, or undetectable Hepatitis C for twelve or more weeks after the end of treatment, of ≥93% across genotypes 1a, 2a, 3a, 4, 5 and 6.