Many clinical trials of hepatitis C treatment combine patients with HCV genotypes 2 and 3 when determining regimens and reporting results. Genotypes 2 and 3 are both considered "easier to treat" compared with genotype 1 and 4, but they are not as similar as often assumed, according to a study in the January 2008 Journal of Viral Hepatitis.

Researchers with the Canadian Pegasys Study Group re-assessed all treatment-naive patients with genotype 2 or 3 participating in a large non-randomized, open-label, expanded-access trial evaluating 180 mcg/week pegylated interferon alpha-2a (Pegasys) plus 800 mg/day ribavirin for 24-48 weeks. A total of 180 patients were analyzed, 72 (40%) with genotype 2 and 108 (60%) with genotype 3.

Results

Conclusion

In conclusion, the authors wrote, "There is significant interaction between cirrhosis and genotype 3 leading to a poor antiviral response in such patients requiring an alternate management strategy."

Based on these findings, they suggested that genotype 2 and 3 patients should be analyzed separately in future clinical trials.

These results agree with those from a recent subanalysis of the POWeR study, another Canadian trial that used pegylated interferon alfa-2b (PegIntron) plus ribavirin. In that study, too, genotype 3 patients had a lower SVR rate than genotype 2 patients, which was attributable to a lower end-of-treatment response rate. The POWeR investigators also recommended that researchers should avoid combining genotype 2 and 3 patients when reporting study results.

1/29/08

References
J Powis, KM Peltekian, SS Lee, and others (Canadian Pegasys Study Group). Exploring differences in response to treatment with peginterferon alpha 2a (40kD) and ribavirin in chronic hepatitis C between genotypes 2 and 3. Journal of Viral Hepatitis 15(1): 52-57. January 2008.