Efficacy and safety of subcutaneous interferon beta-1a in relapsing-remitting multiple sclerosis: Further outcomes from the IMPROVE study

BACKGROUND: The IMPROVE study demonstrated that the fetal bovine serum (FBS)- and human serum albumin (HSA)-free formulation of subcutaneous (sc) interferon (IFN) beta-1a had beneficial effects on the numbers of combined unique active magnetic resonance imaging (MRI) lesions in relapsing-remitting multiple sclerosis (RRMS). Here we report additional MRI endpoints (including post hoc analyses), and clinical efficacy, safety, and immunogenicity outcomes. METHODS: Patients with active RRMS were randomized (2:1) to IFN beta-1a, 44 mcg sc three times weekly (tiw) (n=120), or placebo (n=60), for 16 weeks (double-blind phase). All patients then received IFN beta-1a, 44 mcg sc tiw, for 24 weeks (rater-blind phase). Patients underwent MRI brain scans every 4 weeks. RESULTS: Compared with placebo, there was a 68% reduction in the mean cumulative number of new gadolinium-enhancing lesions with IFN beta-1a as early as week 4 (p