A multicenter, open-label, phase II study of the immunogenicity and safety of a new prefilled syringe (liquid) formulation of Avonex in patients with multiple sclerosis.

Background: A new liquid formulation of Avonex (interferon beta-1a [IFNbeta-1a]) in a prefilled syringe has been developed to make administration of the drug easier for patients with multiple sclerosis (MS). This formulation does not contain human serum albumin (HSA), often added to interferon (IFN) products for stabilization. However, formulation changes may alter the secondary, tertiary, and quaternary structures of IFNbeta products.