Effect of control selection on sustained viral response rates in genotype 2/3 HCV mono-infected versus HIV/HCV co-infected patients

HCV RNA decline in chronic HCV genotype 2 and 3 during standard of care treatment according to IL28B polymorphism

The IL28 gene is highly associated with sustained viral response (SVR) in patients infected with genotype 1 after standard of care (SOC) treatment with peg-IFN and ribavirin. It is also associated with a steeper first phase HCV RNA decline during treatment. In genotype 2 and 3 infections, these correlations are less obvious. We studied the IL28B association to rapid viral response (RVR), SVR, first and second phase HCV RNA decline during treatment in 100 HCV mono-infected and 13 HCV/HIV co-infected patients. We found a significantly higher mean baseline HCV RNA level in IL28B SNP CC than non-CC mono-infected patients, 6.99 vs 6.30 log(10) IU/mL (P = 0.02), and a significantly larger median 1st phase decline in patients with CC than non-CC genotype, 2.03 vs 1.37 log(10) IU/mL, respectively. The overall SVR rate in HCV mono-infected patients was 87% vs 77% in HCV/HIV co-infected patients, with no correlation to IL28B SNP. In mono-infected patients with RVR, the SVR rate was high and independent of IL28B genotype. In mono-infected patients who failed to achieve RVR who had IL28B CC and non-CC genotype, 64% and 67% achieved SVR, respectively. In genotype 2 and 3 infected patients, the 1st phase HCV RNA decline was steeper in patients with IL28B CC vs non-CC genotype during SOC treatment. This did not translate into a higher frequency of RVR or SVR. Hence, the clinical relevance of pretreatment analysis of IL28B polymorphisms in genotype 2 and 3 infected patients can be questioned in patients with expected high SVR rate.