Longitudinal prospective evaluation of treatment effects, MRI and neutralizing antibodies in multiple sclerosis patients treated long-term with interferon-β-1b (Betaseron®)

Trials of interferon-β-1b and interferon-β-1a (IFN-β-1b and IFN-β-1a) have shown clinical efficacy in relapsing-remitting multiple sclerosis (RRMS),1-5 despite the fact thatthemechanisms of these effects are largely unknown. Antiviral and antiproliferative effects might contribute to the overall clinical effect in multiple sclerosis (MS), although immunomodulatory effects are considered more important.6 Clinical follow-up of trial patients has been limited to 2-5 years and very little is known about the long-term clinical and magnetic resonance imaging (MRI) effects in INF-β treatment. A confounding variable in understanding the clinical significance of IFNs is the presence of antibodies.