A Study for Tysabri Participant Preference

Treatment tested

• Natalizumab

  Integrin alpha-4/beta-1 inhibitor|Integrin alpha-4/beta-7 inhibitor

Other measures (5)

Key Inclusion Criteria: * Diagnosis of highly active RRMS according to McDonald criteria (2018) and initiating natalizumab treatment is indicated based on current summary of product characteristics (SmPC) * In RRMS participants who are already on natalizumab therapy, continued treatment must be indicated based on current SmPC Key Exclusion Criteria: * Progressive forms of MS * Contraindication to natalizumab treatment according to natalizumab SmPC * Concomitant treatment with other drugs for treating RRMS * Participation in any interventional clinical trial NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.

The primary objective of this study is to collect, evaluate and compare data on participant preference between subcutaneous (SC) and intravenous (IV) natalizumab. The secondary objectives of this study are to evaluate the immunogenicity of SC natalizumab for natalizumab-naïve participants and collect and evaluate data on the multiple sclerosis (MS) disease-relevant parameters (relapse rate, time to first relapse, disability improvement and progression) over 12 months, in participants with natalizumab therapy starting on SC natalizumab or switching from IV natalizumab.