Efficacy and Safety Study of PEG-rIL-29 Plus Ribavirin to Treat Chronic Hepatitis C Virus Infection

PEG-rIL-29 (also known as PEG-interferon lambda) is a unique Type III interferon molecule
that has demonstrated antiviral activity when administered weekly for 4 weeks to
treatment-relapsed and treatment-naive subjects with genotype 1 hepatitis C virus (HCV)
infection. Because PEG-rIL-29 binds to a unique receptor with a more limited distribution
than the receptor for interferon (IFN)-α, it may have the potential to treat HCV without
some of the treatment-limiting side effects associated with IFN-α-based therapies. The
purpose of this Phase 2a/b randomized, controlled, multicenter study is to compare the
safety and efficacy of PEG-rIL-29 and peginterferon alfa-2a, both administered
subcutaneously weekly for up to 48 weeks in combination with daily oral ribavirin, in
treatment-naive subjects with chronic genotype 1, 2, 3, or 4 HCV infection. The initial part
of the study (Phase 2a) will be conducted as an open-label study; the second part of the
study (Phase 2b) will be conducted as a blinded study. The above information provided in
this listing is specific to the Phase 2b portion of the study. In addition, two small
open-label substudies will be conducted to evaluate the efficacy of 24-week treatment with
PEG-rIL-29 and ribavirin in subjects with HCV genotype 1 who have a particular genetic
polymorphism associated with favorable response (n=60) and to evaluate the efficacy of
16-week treatment with PEG-rIL-29 and ribavirin in subjects with HCV genotype 2 or 3 (n=30).