From the HCV Advocate News:

In the August 2006 Journal of Hepatology, M. Silva and colleagues
reported on a study comparing the pharmacokinetics and antiviral
activity of 180 mcg/week pegylated interferon alfa-2a (Pegasys) vs
1.5mcg/kg/week pegylated interferon alfa-2b (Peg-Intron) in 36 patients
with genotype 1 HCV infection. Patients were randomly assigned to
receive Pegasys or Peg-Intron as monotherapy for four weeks, then added
13 mg/kg/day ribavirin for an additional four weeks. Although patients
receiving Pegasys had higher blood drug levels, those receiving
Peg-Intron had significantly greater up-regulation of interferon
response genes, significantly greater maximum and average declines in
HCV RNA, and were more likely to achieve at least a 2-log reduction in
HCV viral load by week 8 (72% vs 44%). [...]

In an accompanying editorial, however, P. Jansen and H. Reesink
cautioned against drawing premature conclusions about which form of
pegylated interferon is better. [...] A larger study called IDEAL is due
to report comparative SVR data for Pegasys vs Peg-Intron in the first
half of 2007. “For the industry these trials are, economically speaking,
life or death,” the authors concluded. “We should continue to make sense
of the data and we should not decide too quickly that one drug is better
than the other.”

Full text and more news at
http://www.hcvadvocate.org/news/newsRev/2006/HJR-3.16.html

Thomas