12-week grazoprevir/elbasvir is highly effective in hepatitis C virus genotype 1 (HCV-1) infection. The efficacy of 8-week regimen for naïve patients with mild fibrosis is elusive.


HCV-1b naïve patients with mild fibrosis were randomized to 8 (n=41) or 12 (n=41) weeks of elbasvir/grazoprevir. The primary endpoint was SVR12 (HCV RNA < 12 IU/ml at post-treatment week-12).


SVR12 was achieved by 87.8% (36/41) and 100% (41/41) in the full-analysis population and 90.0% (36/40) and 100% (41/41) in the per-protocol population in the 8-week and 12-week arms, respectively (all p=0.055). In the 8-week arm, a significantly lower SVR12 rate was observed among patients with a high viral loads (HVL,>1,500,000 IU/mL, 79% vs. 100%, p=0.042) and those with baseline NS5A-Y93H RAS >15% (40.0% vs. 97.1%, p=0.004). Between-group analysis demonstrated that patients with HVL and Y93H>15% had a substantially lower SVR12 rate in the 8-week arm (40.0%) than the 12-week arm (100.0%). All four HCV-1b relapses had NS5A RAS Y93H> 99% at post-treatment week-12.


Twelve weeks of grazoprevir/elbasvir is highly effective for HCV-1b naïve patients with mild fibrosis. A truncated 8-week grazoprevir/elbasvir regimen might be applied for those with low viral loads or without significant NS5A RAS.


CHC; DAA; abbreviated; elbasvir; grazoprevir; treatment