PEGASYS®: large, branched 40KD PEG attached by stable bonds
}Large PEG (40KD)
}Branched, not linear
}Stable amide bond
}Accessibility to interferon alfa receptor maintained
}Increased serum half-life
}Small volume of distribution
40KD branched PEG
IFNa-2a
large exclusion volume
Size and type of pegylation make a difference
Slide 3. PEGASYS®: large, branched 40KD PEG attached by stable bonds
•PEGASYS® has a large, branched, 40KD polyethylene glycol (PEG), attached to interferon alfa-2a by a stable amide bond. Biological activity is retained as accessibility of the interferon binding site is maintained.
•The large size of the 40KD PEG moiety results in prolonged half-life and restricts its volume of distribution. Thus, the distribution of PEGASYS® is limited to the blood and organs well perfused with blood, such as the liver. PEGASYS® also has reduced clearance compared with conventional interferon alfa.