Subgroup and sensitivity analyses of annualized relapse rate over 2 years in the ADVANCE trial of peginterferon beta-1a in patients with relapsing-remitting multiple sclerosis

ADVANCE was a 2-year, double-blind, placebo-controlled, Phase 3 study in 1512 patients aged 18–65 years with relapsing-remitting multiple sclerosis, which demonstrated that peginterferon beta-1a 125 mcg administered subcutaneously every 2 or 4 weeks led to significant reductions in annualized relapse rate (ARR) compared with placebo. This analysis examined ARR over 2 years in ADVANCE across subgroups. Patients were treated with peginterferon beta-1a every 2 weeks or every 4 weeks, or placebo during Year 1. Thereafter, patients on placebo were re-randomized to peginterferon beta-1a every 2 weeks or every 4 weeks (delayed treatment). Subgroup analyses were conducted by demographics and baseline disease characteristics. The following results compared ARR in these subgroups for patients in continuous 2-week treatment versus continuous 4-week treatment. ARR was similar in most demographic and baseline disease characteristic subgroups evaluated within the peginterferon beta-1a every-2-week arm or every-4-week arm over 2 years. Although for both doses some differences in the point estimates for ARR were noted among the subgroups, considerable overlap in the confidence intervals suggested that the efficacy of peginterferon beta-1a is similar in all patients irrespective of gender, age, body weight, geographical region, and disease activity at initiation of treatment. Within each peginterferon beta-1a dosing group, ARR was generally similar across most subgroups.