ABSTRACT
Pegasys is a modified form of the recombinant human interferon alfa-2a, Roferon A. It differs from the natural molecule in having an additional methionine residue at its Nterminus and in lacking glycosylation. It also has an additional single-branched bismonomethoxy PEG chain, linked in υitro to a lysine residue via an amide bond, which is not present in Roferon A. It is produced in E. coli and undergoes several purification steps, including affinity, ion exchange, and size exclusion chromatography. The final product is presented as a solution containing peginterferon alfa-2a (active), as well as sodium chloride, polysorbate 80, benzyl alcohol, sodium acetate trihydrate, and acetic acid as excipients. Pegasys is supplied in vials for subcutaneous administration.
