Schering-Plough Corp.'s Pegintron provides better duration of response and no new side effects with fewer injections compared to the company's Intron A conventional interferon. But it is not clear whether Pegintron will be prescribed to all patients infected with hepatitis C virus (HCV). For one thing, Pegintron so far has received European approval as monotherapy only, and combination therapy is standard in many patients. In addition, there is not consensus among physicians regarding whether every HCV-infected patient should be treated at all.

Pegintron peginterferon alfa-2b is a longer-acting form of Intron A that uses polyethylene glycol (PEG) technology from Enzon Inc. (ENZN, Piscataway, N.J.), which stands to earn mid-high single-digit royalty on all worldwide sales of Pegintron in all indications.