Various factors contribute to optimal response to interferon-based therapy for chronic hepatitis C, including HCV genotype, baseline HCV viral load, doses and duration of therapy, and degree of early response. Genotype is often regarded as the most critical of these factors, with genotypes 1 and 4 considered harder to treat than genotypes 2 and 3.

As reported at the 43rd annual meeting of the European Association for the Study of the Liver last month in Milan, investigators performed an analysis to determine the relative importance of HCV genotype and response at weeks 4 (rapid virological response, or RVR) and 12 (early virological response, or EVR) in predicting sustained virological response (SVR), or continued undetectable HCV RNA 24 weeks after completion of therapy.

The analysis included 1383 participants in 3 randomized clinical trials treated with 180 mcg/week pegylated interferon alfa-2a (Pegasys) plus ribavirin at doses of 800 mg/day for genotypes 2 or 3 or 1000-1200 mg/day for genotypes 1 or 4. Patients with genotypes 2 or 3 were treated for 24 weeks and those with genotypes 1 or 4 for 48 weeks.

Results

• Virological response rates at the different time points by genotype are shown in the table.

• Overall, HCV genotype had a significant influence on response during treatment and on SVR.

• However, SVR rates were similar across genotypes among patients who achieved RVR.

• A multiple logistic regression analysis confirmed that RVR predicted SVR overall (OR 7.5 vs no RVR; P<0.0001).

• In patients with RVR, however, genotype was not a significant predictor of SVR.

Conclusion

"Patients achieving RVR have a high probability of SVR, regardless of genotype," the investigators concluded. "RVR and EVR can be used to identify patients most likely to achieve an SVR."

University of North Carolina, Chapel Hill, NC; Henry Dunant Hospital, Athens, Greece; Virginia Commonwealth University Medical Center, Virginia; IST GmbH, Mannheim, Germany; JW Goethe University Hospital, Frankfurt, Germany.

5/13/08

Reference
MW Fried, SJ Hadziyannis, M Shiffman, and others. Rapid virological response is a more important predictor of sustained virological response (SVR) than genotype in patients with chronic hepatitis C virus infection. 43rd annual meeting of the European Association for the Study of the Liver (EASL 2008). Milan, Italy. April 23-27, 2008.