A single IL28B genotype SNP rs12979860 determination predicts treatment response in patients with chronic hepatitis C Genotype 1 virus.

Background: Recent studies have suggested that host genetics may be useful for predicting drug response and have supported the recommendation that single polynucleotide polymorphisms (SNPs) of IL28B should be investigated when treating hepatitis C virus (HCV)-1 infected patients. The aim of this study was to determine whether a single IL-28B genotype SNP rs8099917 or rs12979860 determination is sufficient to predict treatment failure in patients with chronic HCV.

Methods: A total of 198 patients were included; mean (±standard deviation) age was 47±12 years and 140 (71%) were men. One hundred and fifty-six (79%) patients were infected with HCV genotype 1 and 42 (21%) with HCV genotypes 2 or 3. One hundred and eight (55%) patients had sustained virologic response (SVR). Two SNPs in the IL-28B were analyzed (rs8099917 and rs12979860).

Results: A total of 115 (58%) patients had rs8099917 TT genotype and 61 (31%) had rs12979860 CC genotype. Rs8099917 TT and rs12979860 CC genotypes were associated with SVR in HCV genotype 1 patients [odds ratio=2.60 (1.36-5.00), P=0.004 and odds ratio=3.30 (1.58-6.90), P=0.03 respectively]. No association was found between SNPs and SVR in HCV genotype 2 or 3 patients.

Conclusion: This study confirms that SNPs rs8099917 and rs12979860 used alone may be useful for predicting the outcome of HCV treatment. In a rational and cost-effective approach, determination of only one of these two SNPs is sufficient for predicting SVR. Because of the highest predictive SVR associated with rs12979860 CC compared with the rs8099917 TT (respective positive predictive value: 72% vs. 63%, P=ns), rs12979860 determination alone is sufficient for predicting interferon response.