Peginterferon alfa-2a are interferon proteins bound to polyethylene glycol (PEG) molecules resulting in higher and more prolonged serum interferon concentrations. It has antiviral, antiproliferative and immune-regulating activity. Interferons are activated when it interacts with cells through high affinity cell surface receptors. The effects of this activation include the induction of gene transcription, inhibition of cellular growth, alteration of cellular differentiation, interference with oncogene expression, alteration of cell surface antigen expression, increase in phagocytic activity of macrophages and augmentation of cytotoxicity of lymphocytes for target cells.