November 12, 2001
Dr. Peter Ferenci from the University of Vienna presented this report at the 52nd annual meeting of the AASLD in Dallas, Texas. In previous presentations this group of investigators in the U.S. and Europe have shown that failure to achieve a greater than two log or negative status of HCV-RNA after 12 weeks of treatment with pegylated interferon and ribavirin is highly predictive of a lack of sustained virologic response (SVR). In this report, the objective was to investigate the effect of genotype and adherence to treatment on the positive and negative predictive value for sustained virologic response using the 12-week response of a greater than two log drop or negative HCV-RNA. All patients were treated with pegylated interferon alfa 2-a and ribavirin in a large randomized trial and the data was analyzed retrospectively for positive predictive value and negative predictive value. Genotype 1 patients achieving a 12-week response had a 57% chance of achieving SVR whereas those genotype 1 patients not achieving a response at 12 weeks had a 98% chance of not achieving a sustained viral response. On the other hand, genotype 2 and 3 patients achieving a response at 12 weeks had a 77% chance of going on to a sustained viral response.
The second part of the report centered on the issue of adherence to therapy. Patients taking 80% of the doses of both medications at least 80% of the prescribed time had a 75% chance of achieving sustained viral response while those who fell below the 80% mark had only a 48% chance of going on to SVR. Combining both the 12-week response data and adherence data revealed that genotype 1 patients adhering to the therapy have a 67% chance of achieving viral clearance while those below the 80% mark have only a 40% chance. For genotype 2 and 3 patients, 86% achieved sustained viral clearance if they met these criteria while those who didn't had only a 58% chance of viral clearance.
This report is very important as it conclusively shows that early viral response is probably the most important predictor of which patients will go on to clear virus. It also points to the importance of adhering to therapy which when combined with early viral response leads to the highest achievable levels of sustained viral clearance. These data will now allow us to predict which patients will be most likely to clear virus thus concentrating our efforts on these individuals and making therapy more cost effective.