Aim: To compare 14 and 24 weeks treatment to patients with HCV genotype 2 or 3 infection and rapid virological response (RVR).
Materials and methods: Patients included in two Scandinavian trials, one nonrandomized pilot trial (n=122) and one randomized controlled trial (RCT) (n=428) were entered into a pooled database. In both trials treatment naïve patients with genotype 2 or 3 were treated with pegylated interferon alpha 2b (1.5 microg/kg, subcutaneous) weekly and ribavirin (800-1400 mg, orally) daily. Primary endpoint was sustained virological response (SVR). RVR was defined as HCV RNA less than 50 IU/ml after 4 weeks of treatment. In the pilot trial all patients with RVR were treated for 14 weeks and in the RCT patients with RVR were randomised to either 14 or 24 weeks treatment. Patients treated per protocol were included in the primary analysis. The noninferiority margin was set to be 10% between the two groups with a one-sided 5% significance level.
Results: In patients with RVR and genotype 2 or 3 SVR was obtained in 181 of 199 (91.0%) and 93 of 98 (94.9%) after 14 and 24 weeks treatment, respectively. The observed difference in SVR rates was 3.9% (90% confidence interval: +1 to -8.8). The relapse rate was highest among those older than 40 years and those with genotype 3 and high viral load, but prolongation of treatment from 14 to 24 weeks did not reduce the relapse rate substantially in any of these groups.
Conclusion: In patients with HCV genotype 2 or 3 infection and RVR 14 weeks treatment is noninferior to 24 weeks.