A phase III study evaluating the efficacy and safety of MBP8298 in secondary progressive MS

Abstract

To evaluate the efficacy and safety of MBP8298 in subjects with secondary progressive multiple sclerosis (SPMS) who express human leukocyte antigen (HLA) haplotype DR2 or DR4 (DR2(+) or DR4(+)). This multicenter randomized 2-year, double-blind, placebo-controlled study included 612 subjects with a diagnosis of SPMS and an Expanded Disability Status Scale (EDSS) score of 3.5-6.5, stratified according to baseline EDSS score (3.5-5.0, or 5.5-6.5) and HLA haplotype (DR2(+) or DR4(+), or DR2(-)/DR4(-)). Upon entry of 100 DR2(-)/DR4(-) subjects, further study enrollment was limited to DR2(+) or DR4(+) subjects. Subjects were randomly assigned to either 500 mg MBP8298 or placebo, given by IV injection once every 6 months for 2 years. The primary outcome measure was time to progression by ≥1.0 EDSS point (or 0.5 point if baseline EDSS was 5.5 or higher), confirmed 6 months later. Secondary outcomes included mean change in EDSS, mean change in Multiple Sclerosis Functional Composite, MRI changes, annualized relapse rate, and quality of life. There were no significant differences between treatment groups in either the primary or secondary endpoints. MBP8298 was well tolerated in all treated subjects with no safety issues identified. In the population studied, treatment with MBP8298 did not provide a clinical benefit compared to placebo. This study provides Class 1 evidence that MBP8298 is not effective in patients with SPMS who are HLA DR2(+) or DR4(+).