A drug used to treat melanoma and hepatitis C. It is also being studied in the treatment of other types of cancer. It is used under the brand name Sylatron to treat melanoma in patients who have had surgery to remove cancer that has spread to lymph nodes. It is used under the brand name PEG-Intron to treat hepatitis C infections. Peginterferon alfa-2b is a form of interferon alfa (a substance normally made by cells in the immune system) linked to a substance called PEG, which makes the drug stay in the body longer. Peginterferon alfa-2b is made in the laboratory. It is a type of cytokine and a type of biological response modifier. Also called SCH 54031.