Peginterferon beta-1a: a review of its use in patients with relapsing-remitting multiple sclerosis.

Peginterferon beta-1a (Plegridy™), an interferon beta-1a conjugated to a methoxy polyethylene glycol (PEG) molecule, is available in the EU and the USA for the treatment of adults with relapsing-remitting multiple sclerosis (RRMS). In a 96-week multinational, phase III study in this patient population (ADVANCE), subcutaneous peginterferon beta-1a 125 µg every 2 weeks significantly reduced the adjusted annualized relapse rate over 48 weeks, compared with placebo, corresponding to 36% fewer relapses per patient-year. Significant reductions versus placebo were also observed in the risk of relapse and disability progression, the number of new or newly enlarging T2-weighted hyperintense lesions, and various other magnetic resonance imaging endpoints. The efficacy of peginterferon beta-1a was sustained over 96 weeks, with preliminary data from the first year of an ongoing 2-year extension of ADVANCE indicating continued benefit longer-term. In ADVANCE, peginterferon beta-1a had an acceptable tolerability profile that was consistent with that of established interferon beta treatments. Adverse events were generally mild or moderate in severity, with injection-site erythema and influenza-like illness reported most commonly. Amongst other adverse events of special interest, peginterferon beta-1a was not associated with an increased risk of autoimmune disorders, depression/suicidal ideation, infections or seizures. In the absence of head-to-head studies, definitive conclusions on the comparative efficacy and tolerability of peginterferon beta-1a versus existing therapies are not yet possible. Although final data from the extension of ADVANCE are awaited, current evidence suggests subcutaneous peginterferon beta-1a every 2 weeks extends the treatment options currently available for adults with RRMS, with the dosing regimen imparting potential compliance advantages over non-PEGylated interferon beta formulations that require more frequent administration.