Conditions: Secondary Progressive Multiple Sclerosis
Keywords: Natalizumab secondary multiple sclerosis MS SPMS Tysabri
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 889
Healthy volunteers: no

Brief summary:
This is a Phase 3b, multicenter, international study conducted in 2 parts. Upon completion of the placebo-controlled period (Part 1), participants will have the option of enrolling in a 2-year open-label extension (Part 2).

Part 1: The primary objective of the study is to investigate whether treatment with natalizumab slows the accumulation of disability not related to relapses in participants with secondary progressive multiple sclerosis (SPMS).

The secondary objectives of Part 1 of this study are to determine the proportion of participants with consistent improvement in Timed 25-Foot Walk (T25FW), the change in participant-reported ambulatory status as measured by the 12-item MS Walking Scale (MSWS-12), the change in manual ability based on the ABILHAND Questionnaire, the impact of natalizumab on participant-reported quality of life using the Multiple Sclerosis Impact Scale-29 Physical (MSIS-29 Physical), the change in whole brain volume between the end of study and Week 24 using magnetic resonance imaging (MRI) and the proportion of participants experiencing progression of disability as measured by individual physical Expanded Disability Status Scale (EDSS) system scores.

Part 2: The primary objective of Part 2 of the study is to evaluate the safety profile of natalizumab in participants with SPMS.

The secondary objectives of Part 2 of the study are to investigate long-term disability (based on clinical or participant-reported assessments) in participants with SPMS receiving natalizumab treatment for approximately 4 years and to assess change in brain volume and T2 lesion volume.

Detailed description:

Arms:
arm 1: In Part 1 participants were randomized to receive 300 mg of natalizumab intravenously (IV) every 4 weeks for 96 weeks. In Part 2 participants transitioned to receive open-label natalizumab 300 mg IV every 4 weeks for at least 96 weeks. arm 2: In Part 1 participants were randomized to receive placebo IV every 4 weeks for 96 weeks. In Part 2 participants transitioned to receive open-label natalizumab 300 mg IV every 4 weeks for at least 96 weeks.

Interventions: intervention 1: natalizumab intervention 2: Placebo
Intervention descriptions: intervention 1: Administered as specified in the treatment arm intervention 2: Matched placebo in part 1

Protocol document: