Incidence, characterization, and clinical impact analysis of peginterferon beta1a immunogenicity in patients with multiple sclerosis in the ADVANCE trial.

Background: Efficacy of interferon beta in multiple sclerosis (MS) can be dampened in patients who develop neutralizing antidrug antibodies (NAbs). Peginterferon beta1a is an interferon conjugated with a polyethylene glycol (PEG) moiety. Pegylation increases a drug's half life and exposure, and may also reduce immunogenicity. Objective: The objective of this study was to characterize the incidence and impact of immunogenicity to peginterferon beta1a over 2 years in patients with MS. Methods: Patients with relapsing-remitting MS (N = 1512) were randomized to subcutaneous peginterferon beta1a 125 mu g every 2 or 4 weeks, or placebo, for 1 year; patients in the placebo group were rerandomized to active treatment in year 2. The incidence and titers of binding antibodies (BAbs) and NAbs to interferon and antibodies to PEG (anti-PEG) were assessed in analytically validated assays. The clinical impact of immunogenicity on relapse and magnetic resonance imaging endpoints was evaluated. Results: Over 2 years, 6%, less than 1%, and 7% of patients developed anti-interferon BAbs, NAbs, and anti-PEG antibodies, respectively. There was no discernible clinically meaningful effect of antibody status on the pharmacodynamic, efficacy, or safety parameters evaluated, although these analyses were limited by the low incidence of treatment-emergent antibodies. Conclusion: The treatment effect of peginterferon beta1a in patients with relapsing-remitting MS is not expected to be attenuated by immunogenicity.