In patients infected with genotype 1 slow response to antiviral therapy i.e. lack of RVR, is associated with a significantly higher rate of relapse in those who go on to achieve undetectable HCV RNA at 12 weeks rather than at 4 weeks into treatment. Extending treatment for a further six months reduces this relapse rate considerably. By extending treatment in patients infected with genotype 3 who had previously relapsed following only 14 weeks of therapy to 24 weeks reduced relapse rates. Thus, it is anticipated that by extending treatment from 24 to 48 weeks in those who fail to achieve a RVR (i.e. slow responders) but who do achieve a complete EVR we hope to prevent relapse off treatment. A potential added benefit of achieving SVR in this patient population, many of whom are already at high risk of T2DM, is that it may reduce the virally mediated component of IR.