Of 328 patients who were assigned to a treatment group, 223 had a baseline HCV RNA level ≥400,000 IU/mL (84 C/C, 108 T/C, 31 T/T) and 105 had a baseline HCV RNA level <400,000 IU/mL (27 C/C, 60 T/C, 18 T/T). The rs12979860 genotype was determined for 97 of 150 (64.7%) patients with an RVR assigned to group D. The majority of these patients (60 [61.9%]) had the homozygous C/C genotype, and 37 individuals

carried the T allele (35 had the T/C genotype, 36.1%; 2 had the T/T genotype, FK228 2.1%). Of 97 patients with an RVR assigned to group D and with a known rs12979860 genotype, 93 (95.9%) achieved an EoT response, of whom four were lost to follow-up. Among the 89 patients with known end-of-follow-up results, 78 patients (87.6%) achieved an SVR and 11 (12.4%) relapsed. SVR rates exceeded 80%, regardless of rs12979860 genotype (Fig. 3A). Relapse rates were numerically lower in patients with the C/C genotype, but did not differ significantly from those in patients VX-765 nmr carrying the T allele (T/C and T/T combined) overall (Fig. 3B). The results were similar when the analysis was restricted to genotype 1 patients (Fig. 3C,D). Only one of the 17 HCV genotype 4 patients with an RVR relapsed. This individual had the C/C genotype. Among individuals with the C/C genotype and baseline HCV RNA levels of <400,000 IU/mL and ≥400,000 IU/mL, respectively, 5.0% (1/20) and 13.9% (5/36) of patients relapsed. Among those patients with

T allele (T/C or T/T genotype) and baseline HCV RNA level <400,000 IU/mL the relapse rate was 11.5% (3/26). Only seven patients with T allele and a baseline HCV RNA level ≥400,000 IU/mL achieved an RVR: five achieved an SVR and two relapsed. The rs12979860 genotype was determined for 183 of 289 (63.3%) patients without an RVR who achieved an EVR at week 12 and were randomized to groups A or B. Fifty (27.3%) patients had the

homozygous C/C genotype and 133 individuals carried the T allele (99 [54.1%] had the T/C genotype, and 34 [18.6%] had the T/T genotype). The distribution of rs12979860 genotypes was similar in groups A and B (Fig. 1). Among patients with known rs12979860 genotypes in groups A and B, respectively, 82/93 (88.2%) and 63/90 (70.0%) achieved an EoT response, of whom 51/82 (62.2%) and 51/63 (81.0%) achieved an SVR, and 31/82 (37.8%) and 12/63 (19.0%) patients relapsed. SVR rates were numerically Reverse transcriptase higher in patients treated for 72 weeks regardless of rs12979860 genotype, although the positive impact of extended treatment was magnified in patients who carried a T allele (Fig. 4A). Relapse rates, the primary outcome in the original study, were numerically lower in patients treated for 72 weeks (20.0%, 95% confidence interval [CI] = 10.2-30.9) compared with 48 weeks (26.9%, 95% CI = 27.3-49.2; odds ratio [OR] = 2.58; 95% CI = 0.32-6.83), and were markedly lower in patients who carried a T allele (48 versus 72 weeks: 42.9%, 95% CI = 29.7-56.8 versus 18.8%, 95% CI = 8.9-32.