Non-A/non-B hepatitis - also known as hepatitis C - is an infectious liver disease that strikes about 180,000 Americans every year, largely through contact with infected blood either in a transfusion or through the sharing of intravenous needles by drug addicts. In its chronic form, it can lead to cirrhosis, liver failure and in some cases death.

With hepatitis C, however, some drug industry analysts predict alpha interferon sales could approach $1 billion a year. About half of the 180,000 acutely infected with hepatitis C develop the chronic form of the disease - which is marked by sustained inflammation of the liver - making them candidates for the drug.