Sofosbuvir for Previously Untreated Chronic Hepatitis C Infection

Abstract

In their article on the use of sofosbuvir in previously untreated patients with chronic hepatitis C virus (HCV) infection in two phase 3 studies (May 16 issue),¹ Lawitz et al. conclude that the addition of sofosbuvir was effective in patients who were infected with HCV genotype 1, 4, 5, or 6 (NEUTRINO trial). However, response rates in the group that received sofosbuvir and ribavirin were lower among patients with genotype 3 infection than among those with genotype 2 infection (FISSION trial). Although for the latter trial, the authors provide data on the presence or absence of cirrhosis, baseline viral load, and ribavirin exposure (all factors known to be associated with therapeutic response²), they do not include data on liver steatosis, which is the most important risk factor for a lower sustained virologic response in patients with HCV genotype 3 infection.³ In addition, in the group that received sofosbuvir and ribavirin, the proportion of patients with an HCV RNA level of less than 25 IU per milliliter decreased from 98% at the last observed measurement during the treatment period to 74% at 4 weeks after the end of treatment and to 67% at 12 weeks after the end of treatment. Because patients in this group did not have the immunomodulation associated with the receipt of interferon, it is unclear whether response rates can be maintained after the discontinuation of sofosbuvir, and long-term follow-up is needed.