Genotype, enzyme levels, and viral load are clues to hepatitis C virus outcomes
Sonia Nichols, Hepatitis Weekly
Researchers in Germany report that viral genotype and load, as well as liver enzyme levels, are predictors for treatment outcomes in chronic hepatitis C. Their multicentre, retrospective investigation examined the data for 260 patients in Europe who were treated with pegylated interferon alfa, or with standard interferon. The patients, who underwent therapy for six to 12 months, also received ribavirin.
“A viral load at treatment week four above 450,000 IU/mL and at week 12 above 30,000 IU/mL was 100% predictive for virologic nonresponse in all patients,” reported Thomas Berg and colleagues of Humboldt University-Berlin. Statistical analysis indicated that being of HCV of genotypes 2 or 3, having high levels of alanine aminotransferase before starting treatment, and having a low viral load at baseline were independent predictors for attaining a sustained virologic response.
“None of the latter three factors were predictive for sustained virologic response when analysis was restricted to the subgroup of genotypes 2- and 3-infected patients,” Berg and coauthors wrote. They suggested that by as early as 12 weeks after therapy has begun, doctors can determine whether or not sustained virological response will occur using an HCV RNA cut-off level 30,000 IU/mL. “This algorithm recognises 53.7% of nonresponders previously identified at week 24 of treatment,” they said.
Berg T, Sarrazin C, Herrmann E et al. Prediction of treatment outcome in patients with chronic hepatitis C: significance of baseline parameters and viral dynamics during therapy,” was published in Hepatology (2003;37(3):600-609).
Similar observations for week 12 have been reported from the pivotal study for the approval of Pegasys published by Fried et al in NEJM 2002. The news from this study is the predictive value of week 4 response rather than week 12. These data may correlate well with a study from Ferenci et al from Vienna presented at last years AASLD where the viral kinetics in the first week of pegylated interferon were used to identify non-responders.
For the moment however week 12 seems to be the time to make a decision to stop or continue treatment based on virological response, because of the better documented data available. It has to be mentioned however that all the response data are based on 24/48 weeks of therapy and patients with a slow viral load decline may respond with prolonged periods of treatment.