3.1.3b Pegylated IFN and Ribavirin

Schering’s Pegylated IFN plus ribavirin (Peg-Intron/Rebetrol) has been approved and is the standard treatment ( http://www.niddk.nih.gov/health/digest/pubs/chrnhepc/chrnhepc.htm The recommended dosage for this combination therapy is based on the patient’s weight.  It has recently been suggested that the injection should be given twice a week rather than once a week (Bruno, R et al, Pharmacokinetics of Peginterferon Alfa-2A (40KD, Pegasys) compared to Peginterferon Alfa-2B (12KD, Pegintron) in naive patients with chronic hepatitis C (CHC) Abstract Number: 4203.00.)

In trials where the optimal dose of Peg-Intron was combined with ribavirin, results show a sustained viral response rate of 42% among patients with genotype 1, and of 82% among patients with genotypes 2 and 3, and an overall SVR of 54%.

Clinical trials with Pegasys + Copegus showed a 51% sustained viral response rates (SVR)with genotype 1 patients treated for 48 weeks with 1000–1200mg Copegus, and an 82% SVR in genotype non-1 patients treated for 24 weeks with 800mg Copegus ( www.rocheusa.com/newsroom/current/2003/pr2003011301.html)

Pegasys + Copegus has been approved in the US, but not in Canada. Roche expects to enroll 1,000 patients in a study known as REPEAT (REtreatment with Pegasys in patients not responding to prior Peginterferon alfa-2b/Ribavirin combination therapy)

Research was done adding “regular” IFN (the 3 shots a week) to pegylated IFN plus ribavirin. The authors of the study say that pegylation decreases the effect of IFN by 35%, so they suggested that the two drugs should be combined for maximum antiviral effect, as well as a sustained attack on the virus. 35 patients are enrolled so far (10 non-responders and 25 naive genotype 1 patients). 86% have responded, including 80% of non-responders. The PEG/IFN/RBV combo seems to be safe and response rates are better than for PEG/RBV, however sustained rates are not yet available, and more patients need to be tested (Abstract 12603, Scott M. Gioe, Combining INF alfa 2b with PEG-INF alfa-2b and Ribavirin in the treatment of Non-responders to previous therapy and Naive Genotype 1 patients with Chronic Active Hepatitis C.).

TREATMENT OF RELAPSERS AND NON-RESPONDERS: People who didn’t have sustained viral response to interferon alfa/ribavirin may expect a response rate of around 20% for "non-responders" and 50-60% for relapsers. if they take a course of pegylated interferon alfa/ribavirin (Mark Sulkowski, MD, www.natap.org).