IFN-alfa 2 was the first agent approved for the treatment of chronic HCV. Since the initial trials establishing its efficacy, data regarding treatment duration and dose have evolved. Currently, 2 forms of IFN-alfa that differ by a single amino acid residue are approved for treatment of chronic HCV infection: IFN-alfa 2b (Schering-Plough, Kenilworth, New Jersey) and IFN-alfa 2a (Hoffmann-La Roche, Basel, Switzerland). The recommended dose is 3 million units 3 times each week for up to 12 months.
When used alone in monotherapy, the alfa interferons have similar efficacies, with SRs of only 10% to 20%, with the modestly higher response rates associated with more prolonged therapy. Higher-dose IFN-alfa (ie, > 9 million units per week) results in SRs between 8% and 20% in treatment-naive patients. High-dose IFN-alfa has also been studied in NRs and relapsers, but with mixed results. With prior NR, SRs achieved with higher doses are only between 0% and 4%. In relapsers, SRs range from 20% to 40%. However, side effects are more troublesome with higher doses.
Because of the low overall response rate to standard IFN-alfa, more recent studies have focused on newer regimens, including synthetic IFN (IFN alfacon-1), "combination" therapy (IFN-alfa 2b + ribavirin), and longer-acting IFNs (pegylated IFNs). A number of major pretherapy predictors of NR have been identified, notably HCV genotype 1, the presence of cirrhosis, and higher viral load. In addition, patient's race appears to affect response to IFN, with African Americans having an overall low SR to therapy.
Medscape Gastroenterology. 2001;3(1) © 2001 Medscape
Cite this: Update on Hepatitis C Treatment - Medscape - Feb 15, 2001.