A Swedish national post-marketing surveillance study of natalizumab treatment in multiple sclerosis

Mult Scler. 2011 Jun;17(6):708-19. doi: 10.1177/1352458510394701. Epub 2011 Jan 12.


Background: A post marketing surveillance study was conducted to evaluate safety and efficacy of natalizumab in Swedish multiple sclerosis (MS) patients since its introduction in August 2006 until March 2010.

Methods: Patients were registered in the web-based Swedish MS-registry at 40 locations and evaluated every 6 months. Adverse events and clinical outcomes were recorded.

Results: One thousand one hundred and fifty-two patients were included (71.4% female) and 149 patients stopped treatment; the main reason was planned pregnancy. Anti-natalizumab antibodies were found in 4.5% (52 patients) of which 1.6% displayed persistent antibodies. Serious adverse events were rare, but included three cases with progressive multifocal leukoencephalopathy (PML). There were seven fatal cases, probably unrelated to the natalizumab treatment. For relapsing-remitting MS patients (n=901), mean Expanded Disability Status Scale (EDSS, -10.7%), Multiple Sclerosis Severity Scale (MSSS, -20.4%), Multiple Sclerosis Impact Scale (MSIS-29, physical -9.9%, psychological -13.3%) and Symbol Digit Modalities Test (SDMT, +10.7%) all showed significant improvements during 24 months of treatment with natalizumab. The Swedish web-based MS quality registry proved to function as a platform for post-marketing MS drug surveillance, providing long-term data regarding drug effects and adverse events beyond clinical trials.

Conclusions: Our results indicate that natalizumab is generally well tolerated and has sustained efficacy for patients with active MS, though the risk of PML is still an important concern.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Analysis of Variance
  • Antibodies, Monoclonal / adverse effects
  • Antibodies, Monoclonal / therapeutic use*
  • Antibodies, Monoclonal, Humanized
  • Disability Evaluation
  • Female
  • Humans
  • Immunologic Factors / adverse effects
  • Immunologic Factors / therapeutic use*
  • Leukoencephalopathy, Progressive Multifocal / chemically induced
  • Leukoencephalopathy, Progressive Multifocal / mortality
  • Male
  • Middle Aged
  • Multiple Sclerosis, Chronic Progressive / diagnosis
  • Multiple Sclerosis, Chronic Progressive / drug therapy*
  • Multiple Sclerosis, Chronic Progressive / mortality
  • Multiple Sclerosis, Relapsing-Remitting / diagnosis
  • Multiple Sclerosis, Relapsing-Remitting / drug therapy*
  • Multiple Sclerosis, Relapsing-Remitting / mortality
  • Natalizumab
  • Neuropsychological Tests
  • Product Surveillance, Postmarketing
  • Registries
  • Severity of Illness Index
  • Sweden / epidemiology
  • Time Factors
  • Treatment Outcome
  • Young Adult


  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Immunologic Factors
  • Natalizumab