MRI outcomes in a placebo-controlled trial of natalizumab in relapsing MS

Neurology. 2007 Apr 24;68(17):1390-401. doi: 10.1212/01.wnl.0000260064.77700.fd.


Background: In a 2-year, placebo-controlled trial (the Natalizumab Safety and Efficacy in Relapsing Remitting Multiple Sclerosis [AFFIRM] study), involving 942 patients with relapsing multiple sclerosis (MS), natalizumab significantly reduced the relapse rate by 68% and progression of sustained disability by 42% vs placebo. We report the effect of natalizumab on MRI measures from the AFFIRM study.

Methods: The number and volume of gadolinium (Gd)-enhancing, new or enlarging T2-hyperintense, and new T1-hypointense lesions and brain parenchymal fraction were measured from annual scans obtained at baseline, 1 year, and 2 years.

Results: Compared with placebo, natalizumab produced a 92% decrease in Gd-enhancing lesions (means 2.4 vs 0.2; p < 0.001), an 83% decrease in new or enlarging T2-hyperintense lesions (means 11.0 vs 1.9; p < 0.001), and a 76% decrease in new T1-hypointense lesions (means 4.6 vs 1.1; p < 0.001) over 2 years. Median T2-hyperintense lesion volume increased by 8.8% in the placebo group and decreased by 9.4% in the natalizumab group (p < 0.001); median T1-hypointense lesion volume decreased by 1.5% in the placebo group and decreased by 23.5% in the natalizumab group (p < 0.001). Brain atrophy was greater in year 1 and less in year 2 in natalizumab-treated patients.

Conclusion: Natalizumab has a sustained effect in preventing the formation of new lesions in patients with relapsing multiple sclerosis.

Publication types

  • Clinical Trial, Phase III
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Antibodies, Monoclonal / therapeutic use*
  • Antibodies, Monoclonal, Humanized
  • Brain / pathology*
  • Contrast Media
  • Double-Blind Method
  • Female
  • Follow-Up Studies
  • Gadolinium
  • Humans
  • Image Processing, Computer-Assisted
  • Magnetic Resonance Imaging*
  • Male
  • Middle Aged
  • Multiple Sclerosis, Relapsing-Remitting / drug therapy*
  • Multiple Sclerosis, Relapsing-Remitting / pathology
  • Natalizumab
  • Organ Size
  • Treatment Outcome


  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Contrast Media
  • Natalizumab
  • Gadolinium