Biogen Idec Inc. released the primary efficacy analysis and safety data from its Phase 3 pivotal clinical trial, ADVANCE. Results support peginterferon beta-1a as a potential treatment dosed every two weeks or every four weeks for relapsing-remitting multiple sclerosis (RRMS). Peginterferon beta-1a is a new molecular entity in which interferon beta-1a is pegylated to extend its half-life and prolong its exposure in the body, enabling study of a less frequent dosing schedule.

The primary endpoint of ADVANCE, annualized relapse rate (ARR) at one year, was met for both the two-week and four-week dose regimens. Results showed that peginterferon beta-1a also met the secondary endpoints of risk of 12-week confirmed disability progression, proportion of patients who relapsed and magnetic resonance imaging (MRI) assessments for both dose regimens. Adverse events (AEs), serious adverse events (SAEs) and discontinuations due to AEs were similar across both dose groups.

Overall with both dose regimens studied, the risk-benefit profile of peginterferon beta-1a appears to be favorable. The ADVANCE study included more than 1,500 patients with RRMS and was designed to evaluate the efficacy, safety and tolerability of peginterferon beta-1a compared to placebo at one year. Results showed that when administered via subcutaneous (SC) injection, peginterferon beta-1a 125 mcg demonstrated a significant reduction in ARR at one year.

Compared to placebo, ARR reduction with two-week dosing was 35.6% (p<0.001) and with four-week dosing was 27.5% (p<0.02). Results showed that peginterferon beta-1a also met all secondary endpoints compared to placebo for both dose regimens. Peginterferon beta-1a reduced the risk of 12-week confirmed disability progression as measured by the Expanded Disability Status Scale (EDSS) by 38% in both dosing arms (p<0.04).

Peginterferon beta-1a reduced the proportion of patients who relapsed by 39% in the once every two-week dosing arm (p<0.001) and by 26% in the once every four-week dosing arm (p<0.03). Peginterferon beta-1a reduced the number of new or newly enlarging T2-hyperintense lesions on brain MRI scans by 67% in the once every two-week dosing arm (p<0.001) and by 28% in the once every four-week dosing arm (p<0.001).