The size and placement of pegylated interferon molecules as used in the hepatitis C drug Peg-Intron® affects antiviral activity, according to a study presented October 27 at the annual meeting of the American Association for the Study of Liver Diseases in Boston.
Peg-Intron® is made by Schering-Plough and is used to treat hepatitis C in combination with ribavrin.
According to the researchers, interferon is pegylated to prolong its activity. The pegylation process involves the attachment of a polyethylene glycol (PEG) polymer to the interferon molecule.
In experiments conducted in test tubes, the researchers attached PEG polymers of various sizes at various sites on interferon molecules. The researchers found that pegylated interferon with relatively small PEG polymers attached at a particular site on the interferon molecule had the highest antiviral activity, while pegylated interferon with larger PEG polymers attached at other positions had significantly lower activity.
"This is one of the first studies to relate antiviral activity in vitro to pegylated interferon molecular size and structure, and provides valuable insights into the mechanism of action of these compounds," said Dr. Ira Jacobson, chief of the division of gastroenterology and hepatology at Cornell University's medical school.
Other sources: Schering-Plough