# Efficacy
Keywords: TYSABRI, multiple sclerosis, NEDA, AFFIRM study, clinical relapse, disability progression, radiological disease activity, Gadolinium-Enhancing (Gd+), RRMS, intravenous (IV).

> This page provides detailed information about the efficacy of TYSABRI in treating multiple sclerosis, including key clinical trial data, definitions of no evidence of disease activity (NEDA), and study outcomes for specific patient populations.

## Details
- [Study Information - AFFIRM](#): Overview of the pivotal AFFIRM Phase 3 trial, including endpoints like clinical relapse rates and disability progression in patients treated with TYSABRI.
- [TYSABRI IV and NEDA](#): Explanation of NEDA criteria and analysis of its achievement in both highly active and overall patient populations over two years.
- [References and Abbreviations](#): Definitions of key terms (e.g., Gd+, IV, NEDA, RRMS) and citations for the clinical data presented.
- [Adverse Event Reporting](#): Instructions for reporting adverse events in the UK and Ireland, including contact details for Biogen.