Long-term efficacy of interferon-beta and the role of neutralizing antibodies

Long-term studies are required to assess the importance of neutralising antibodies (NABs) on the clinical efficacy of IFN-beta compounds used for the chronic treatment of multiple sclerosis (MS). The Danish Interferon-beta Project showed, using an anti-viral neutralisation bioassay, large differences in the immunogenecity of the commercially available IFN-beta preparations. Patients with NABs had a significantly increased the relapse rate, and a trend towards faster disease progression measured on EDSS. NABs correlated with higher level of MRI disease activity and hampered pharmacokinetics of neopterin and beta-2-microglobulin. The results add further credence to the argument that the appearance of NABs as a result IFN-beta therapy has a negative clinical impact and can reduce the long-term efficacy of such therapies.