PREDICTION OF RELAPSE AFTER PEGINTERFERON ALFA-2B/RIBAVIRIN THERAPY IN CHRONIC HCV GENOTYPE 1 PATIENTS IS DEPENDENT ON MINIMAL RESIDUAL VIREMA BUT NOT ON IL28B GENOTYPE
Background: Persistence of minimal residual viremia during treatment may explain viral relapse after peginterferon alfa plus ribavirin therapy in chronic hepatitis C. The importance of IL28B genotype for spontaneous and treatment induced viral clearance has recently been proven, but its relevance for viral relapse has not been evaluated yet. Thus, we analyzed relapse rates according to minimal residual viremia and IL28B genotype.
Methods: 225 treatment naïve chronic hepatitis C genotype 1 patients received 1.5 µg/kg/week peginterferon alfa-2b plus 800-1400 mg/d ribavirin for 48 weeks. HCV-RNA levels were quantified with bDNA- (detection limit 615 IU/ml) and TMA-assay (detection limit 5.3 IU/ml). Relapse rates during the follow-up period were prospectively calculated according to baseline viral load ( 800.000 IU/ml) and to viral decline at weeks 4, 8, and 12 of therapy, respectively.
Based on a TaqMan PCR assay, the IL28B genotypes (SNP rs12979860) were CC, CT, or TT (n=140).
Results: Persistence of minimal viremia (bDNA assay negative, but TMA-assay positive) at week 4, 8 or 12 was associated with a relapse risk of 20.6%, 31.8%, and 55.2%. In contrast, relapse rates according to time to first TMA negativity (i.e. either at week 4, 8, or 12) were only 0%, 4.2%, and 8.9%, respectively.
Relapse rates were independent of IL28B genotype in virologic responders as defined by TMA assay. None of the patients who reached TMA negativity within the first 4 weeks suffered a relapse, and the relapse rates were 3.7%, 0%, and 0% and 10.5%, 2.9%, and 12.5% in IL28B rs12979860 genotype CC, CT, or TT carriers who reached undetectable HCV RNA levels for the first time at week 8 and 12, respectively (p=0.344)].
Relapse rates reached 37.5% in case of high baseline viral load and first HCV-RNA undetectability (< 5.3 IU/ml) at week 12.
Conclusion: Viral kinetics during therapy, but not IL28B genotype at baseline, predict the relapse risk after therapy with peginterferon alfa-2b plus ribavirin.
http://www1.easl.eu/easl2011/program/Posters/Abstract1229.htm