[606] COMPARISON OF PEGINTERFERON a-2a AND RIBAVIRIN FOR 12 OR 24 WEEKS IN PATIENTS WITH HCV GENOTYPE 2/3: THE NORDYNAMIC TRIAL

S229sustained virological response rates (SVR) of -80%.Recent studies demonstrate that shorter treatment duration, especially in rapid virological responders, does not compromise SVR rates.Due to different ribavirin dosages and treatment duration used in these trials the role ofribavirin still remains unclear.We conducted a multicentre, prospective, randomised, controlled trial investigating whether a 12 week PEG-IFN a-2a (180 mcg/wk) monotherapy (followed by a 12 wk combination Peg-IFN/RBV (180 mcg/wk+RVB 800mgid = group B) treatment is as effective as a 24 wk standard combination therapy (= group A) with Peg-IFN/RBV Methods: 226/241 screened pts were randomly assigned 1:l to group A and B. End of treatment (EOT) and SVR were assessed by qualitative RT-PCR (i50TU/ml).This non-inferiority study was based on a one-sided 95%confidence interval with a difference of 15% in SVR among group A and B with a power of 80%.Results: 19 pts (8.4%) discontinued treatment before wk 24, 3/226 individuals are still under follow-up.EOT response was 96/103 patients in group A (93%) and 94/95 pts in group B (99%).SVR rates were 83/97 pts (85%) in group A versus 69/95 pts (73%) in group B. Relapse rates were 8% vs 21% in group A and B (p < 0.005).Conclusion: Shortened RBV treatment (group B) seems to be non inferior referring to EOT response (group A vs B: 93% vs 99%) concerning our defined statistical criteria.However, there is a trend of higher SVR in the 24 wk combination arm (group A vs B: 85% vs 73%) explained by a higher relapse rate of 21% in the shortened ribavirin treatment group B. A shortened ribavirin treatment of 12 weeks compromises SVR rates in HCV infected patients with genotype 2 and 3, confirming the results ofthe Accelerate Study.SVR data stratified for low and high virological load, RVR and genotype will be presented at EASL.