Background: The relationship between the complexity of the hypervariable region 1 quasispecies of HCV and responsiveness to therapy is not completely clear.
Objective: To investigate the importance of quasispecies as a predictive factor of rapid (RVR), early (EVR) and sustained (SVR) virologic response.
Methods: Prospective analysis of 82 patients with chronic hepatitis C, genotype 1, treated with peginterferon alfa-2a and ribavirin. Quasispecies (SSCP), HCV-RNA and viral load were determined at baseline and 2, 4, 8 and 12 weeks after beginning treatment.
Results: Less fibrosis and lower serum GGT activity were the only predictive factors for EVR. SVR predictive factors were age < or =40 years, viral load < or =600,000IU/mL, and quasispecies < or =5 bands. By logistic regression analysis, the independent factors determining SVR were age (P=0.011), viral load (P=0.027), and quasispecies (P=0.010). Quasispecies and viral load were not predictive factors of RVR. During treatment, quasispecies decreased rapidly in the SVR group. In non-EVR patients, quasispecies were slightly lower up to 8 weeks and then increased.
Conclusions: Quasispecies are an important predictive factor for SVR, but are no better predictors than viral load. Quasispecies are not predictive factors for RVR or EVR.