The identification of ITPA protective and SLC29A1 risk genotypes still appears to be a current methodology in RBV dosing during hepatitis C virus therapy with DAAs.
Forty patients infected with hepatitis C virus (HCV) genotype 1 and starting anti-HCV therapy with telaprevir in combination with pegylated-IFN/ribavirin were prospectively evaluated for SNPs at the SLC29A1 gene and inosine triphosphatase (ITPA) genes using a real-time PCR system.
Patients (n=169) chronically infected with the hepatitis C virus genotype 1, treated with standard doses of pegylated interferon-α and weight-based doses of ribavirin for up to 48 weeks, were genotyped for 21 variants in nucleoside transporter genes SLC28A2, SLC28A3, SLC29A1, and SLC29A2, selected to include reported functional variants and to span the complete gene loci.
In summary, a SNP rs760370A→G at the ENT1 gene influences the chance of rapid virological response to pegIFN-ribavirin therapy in HIV-infected patients with chronic HCV infection due to HCV genotypes 1 or 4, most likely modulating intracellular ribavirin exposure within hepatocytes.