Mechanism of Action
Plegridy (peginterferon beta-1a) is a subcutaneous injectable therapy, in which interferon beta-1a is pegylated to extend its half-life to permit a less frequent dosing schedule. Interferon-beta (IFN-beta) is a polypeptide, normally produced by fibroblasts, that has antiviral and antiproliferative effects. Binding of IFN-beta to its receptor induces a complex transcriptional response. In immune cells (the most likely target of IFN-beta's therapeutic effect in MS), IFN-beta reduces antigen presentation and T-cell proliferation, alters cytokine and matrix metalloproteinase (MMP) expression, and restores suppressor function. Therapeutic forms of IFN-beta can be produced in bacterial expression systems (IFN-beta1b) or in mammalian cells (IFN-beta1a). The exact mechanism by which Plegridy exerts its effects in patients with multiple sclerosis is unknown.