Optimal treatment duration for patients with HCV genotype 1 infection

The rapidity of viral disappearance on antiviral treatment of chronic hepatitis C with peginterferon/ribavirin correlates with the cure rate. The earlier the virus becomes undetectable, the higher are the response rates. This observation is the basis of response-guided therapy. Viral clearance within the first 4 weeks of treatment is called a rapid virologic response (RVR). The rate of RVR varies among various populations, with the highest one observed in Asian patients and the lowest in African-Americans. In patients infected with genotypes 1 and 4 who experience a RVR treatment with peginterferon/ribavirin can be shortened to just 24 weeks without losing efficacy (sustained virologic rate in RVR are >80%). In contrast, patients with a slow decline in viral load (> 2 log drop after 12 weeks with still detectable virus) may benefit from treatment extension to 72 weeks. Prolonged treatment reduces relapse rates but has no significant effect on cure rates. The data in patients with genotypes 2 and 3 are less clear, mostly because these genotypes are much easier to cure and a benefit is hard to detect. Nevertheless in patients with RVR and low baseline viral load treatment can be safely shortened to 16 weeks. The recently described polymorphism in the region of the IL28B gene may help to select patients for abbreviated or extended treatment schedules.