European Medicines Agency Evaluation of Medicines for Human Use

Background information Currently three interferon (IFN) beta preparations are registered for the treatment of certain stages of multiple sclerosis (MS). Two preparations (Rebif and Avonex) are produced from mammalian cells (CHO) and one preparation (Betaferon) from bacteria (E. coli). The two CHO-derived beta interferons are glycosylated products. The E. coli derived product, which is not glycosylated and differs in two amino acid residues from the CHO expressed products, has about 10 % of the specific activity of the CHO-derived products. All three products differ in formulation, dosing schedule and route of administration. All three products have been reported to induce neutralising antibodies (NABs) in MSpatients (from 5 to more than 50% after one year of treatment). There have been reports suggesting that these antibodies may be associated with a loss of efficacy of treatment.