Impact of interleukin-28B polymorphism on HCV-1 infected patients treated with response-guided therapy

Background: Single nucleotide polymorphisms (SNPs) of interleukin-28B (IL28B) were associated with sustained virological response (SVR) in hepatitis C virus genotype 1 (HCV-1) infected patients treated with a standard 48-week regimen of peginterferon and ribavirin combination. Whether IL28B SNP genotype would be the influential prognosticator for patients treated with response-guided therapy (RGT) is still not well understood. Aims: To investigate the impact of IL28B rs809917 genotype on HCV-1 infected patients treated with RGT. Methods: A total of 128 consecutive treatment-naïve HCV-1 infected patients between July 2006 and July 2011 were analyzed. For rapid virological response (RVR) patients, we allowed an abbreviated 24-week regimen regardless of baseline viral loads; otherwise, a 48-week regimen was implemented (for patients with early virological response). The IL28B rs8099917 SNP genotypes were determined accordingly. Results: A total of 117 patients (91.4%) were of rs8099917 TT genotype and 11 (8.6%) were of GT/GG genotype. Eighty-two of the 128 (64.1%) patients achieved SVR, occurring in 54 of 67 RVR patients (80.6%) and 28 of 61 non-RVR patients (45.9%, p < 0.001). Compared to the GT/GG genotype, patients with the TT genotype had significantly higher SVR rates (67.5% vs. 27.3%; p = 0.008) and low relapse rates (28.2% vs. 70.0%; p = 0.006). The multivariate analysis showed that RVR (odds ratio, 4.51; 95% confidence interval, 1.87–10.90; p = 0.001) and rs8099917 TT genotype (odds ratio, 6.91; 95% confidence interval, 1.53–31.17; p = 0.012) were independent factors associated with SVR. Conclusion: For HCV-1 infected patients who were treated with RGT, the IL28B unfavorable genotype predicted a higher relapse rate; RVR and IL28B favorable genotype were independent factors associated with SVR in patients treated with RGT