Viral kinetics in hepatitis C virus: special patient populations.

The evolution in therapy for chronic hepatitis C virus (HCV) infection to the more recent use of peginterferons in combination with ribavirin has dramatically increased the sustained virological response (SVR) rates versus standard interferon/ ribavirin combination therapy. However, although peginterferon and ribavirin therapy has markedly improved treatment responses overall, factors such as high viral load, genotype 1 infection, obesity, HIV co-infection and African American race continue to pose challenges to optimizing SVR rates. Application of mathematical models may be helpful in understanding why these groups and/or individuals appear to be resistant to interferon (IFN)-based therapy. This article focuses on the viral kinetics and viral kinetic differences among patients infected with HCV genotypes 1 and 2, obese and nonobese patients, and African Americans and Whites.