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Background and Aim: Chronic hepatitis C genotype 2 patients show high susceptibility to pegylated interferon plus ribavirin therapy (PEG/RBV). However, the differences in response to therapy between genotypes 2a and 2b, and the efficacy of prolonged therapy for refractory patients have not been evaluated. We investigated the differences in response to PEG/RBV between each genotype and examined the efficacy of prolonged therapy., Methods: A total of 343 chronic hepatitis patients infected with hepatitis C virus (HCV) genotype 2 (2a: n = 195; 2b: n = 148) were enrolled in this study. All patients received PEG/RBV for 24 (24 week group, n = 242) or more weeks (prolonged group, n = 101). We analyzed the differences in virological response between genotypes 2a and 2b. Clinical and virological factors of patients in the 24-week group and the prolonged treatment group were matched using propensity score analysis, and the efficacy of prolonged therapy established by comparing time of serum HCV disappearance for each genotype., Results: Virological response tended to be higher for genotype 2a compared with genotype 2b; however, there was no significant difference in sustained virological response rates between genotypes (2a: 78.3%; 2b: 70.2%; P = 0.19). After propensity score matching, the adjusted P-value for sustained virological response rate was significantly different for genotype 2b patients with undetectable HCV-RNA between weeks 5 and 8, and for genotype 2a patients with detectable HCV-RNA at week 8., Conclusion: Prolonged therapy with PEG/RBV may be effective when serum HCV-RNA is detectable at week 4 and week 8 for genotype 2b and 2a patients, respectively., (© 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.)

Chronic HCV-infected patients tend to have vitamin D deficiency, suggesting that vitamin D supplementation may enhance the efficacy of treatment with pegylated interferon (PEG-IFN) and ribavirin (RBV). We therefore assessed the effects of vitamin D supplementation on viral response to PEG-IFN/RBV. Eighty-four patients with HCV genotype 1b were randomized, 42 to oral vitamin D supplementation (1000 IU/day) and 42 to nonsupplementation (control), from week 8 to the end of PEG-IFN/RBV therapy. The primary end point was undetectable HCV RNA at week 24 (viral response [VR]). VR rate at week 24 was significantly higher in the vitamin D than in the control group (78.6% vs 54.8% P = 0.037). Adverse events were similar in both groups. When patients were subdivided by IL28B SNP rs8099917 genotype, those with the TT genotype group showed a significantly higher VR rate at week 24 with than without vitamin D supplementation (86.2% vs 63.3% vs P = 0.044). Although patients with the TG/GG genotype, who were relatively resistant to PEG-IFN treatment, had similar VR rates at week 24 with and without vitamin D supplementation, the decline in viral load from week 8 to week 24 was significantly greater with than without vitamin D supplementation. Multivariate analysis showed that rs8099917 genotype and vitamin D supplementation contributed significantly to VR at week 24. SVR rates were similar in the vitamin D and control groups [64.3% (27/42) vs 50% (21/42), P = 0.19]. Vitamin D supplementation may enhance the effects of PEG-IFN/RBV in HCV genotype 1b-infected patients., (© 2013 John Wiley & Sons Ltd.)