Ascend study of natalizumab efficacy on disability in patients with secondary progressive multiple sclerosis (SPMS): Baseline demographics and disease characteristics

Background: ASCEND is a fully enrolled, international, multicenter, randomized, placebo‐controlled study of natalizumab's effects on disability progression in SPMS patients. Methods: Natalizumab‐naive adults with SPMS and Expanded Disability Status Scale (EDSS) score 3.0‐6.5 were enrolled. Patients (N=889) were randomized 1:1 to receive intravenous natalizumab 300 mg or placebo (double‐blind) every 4 weeks for 2 years. Assessments include disability progression and changes in walking ability, dexterity, cognition, quality of life, and brain volume. Results: Baseline mean patient age was 47.2 years; 62% female, 77% prior MS medications, 27% prior immunosuppressant therapy, 83% relapse‐free in the prior year, and 55% anti‐JC virus antibody positive at screening. Times (mean/ median) since first MS symptom, MS diagnosis, and SPMS diagnosis were 16.5/16.0, 12.0/11.0, and 4.8/3.7 years, respectively. Baseline assessment scores (mean/median) were EDSS 5.6/6.0; Multiple Sclerosis Severity Score 6.3/6.4; Timed 25‐ Foot Walk 13.7/11.2 seconds; 9‐Hole Peg Test (9HPT) dominant hand 34.8/28.6 seconds; 9HPT nondominant hand 37.2/29.7 seconds; 12‐item MS Walking Scale 68.6/72.9. Conclusions: Baseline functional disability test scores are consistent with a disabled SPMS population. Results will be presented by low/high EDSS subgroups.