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Infergen is the brand name for consensus interferon. It is a totally artificial alfa interferon, and is chemically different from the interferon in PegIntron and Pegasys. Infergen was developed by Amgen, and was sold to InterMune. They sold it to Valeant Pharmaceuticals. Valeant is now selling it again to another company. Infergen is not available yet as a pegylated interferon, so it must be taken several times each week, preferably daily. The FDA indication uses a low dose of Infergen three times weekly. That is not the best way.We use a daily dose of 15 mcg, and a few patients take 22.5 mcg daily. We use Infergen in Pegasys nonresponders, and about 20% respond to daily Infergen plus ribavirin.The length of treatment is based on the amount of liver fibrosis. At AASLD 2007 the results of the Direct trial were presented. This was a medium sized study where peginterferon nonresponders were given Infergen and ribavirin daily. Many of the patients had stage 3 or 4 fibrosis. About ten percent were sustained viral responders. Many of the patients who responded relapsed after the treatment was stopped. This was expected since prolonged therapy was not allowed. If you look at any large study of patients with HCV, you will find that patients with stage 3 or 4 fibrosis have a high relapse rate. We try to treat for 2 years which helps to reduce the relapse rate. There are a few studies comparing 72 weeks to 48 showing better results with longer treatment. I have not seen large randomized studies comparing one year to two years of treatment. |