title: Natalizumab and drug holiday in clinical practice: an observational study in very active relapsing remitting multiple sclerosis patients.
abstract: BACKGROUND
  In order to reduce the risk of progressive multifocal leucoencephalopathy when using natalizumab for more than 12 months, a 6-month drug holiday has been discussed. However, the consequences on short term disease activity have been poorly assessed.
  
  
  OBJECTIVE
  The aim of this study was to assess clinical and radiological disease activity within 6 months after stopping natalizumab in very active relapsing remitting Multiple Sclerosis (RRMS) patients.
  
  
  METHODS
  In 8 hospitals from Western France, we retrospectively collected clinical and MRI data from consecutive RRMS patients treated with natalizumab for at least 6 months, and who stopped the drug for various reasons except therapeutic failure. Patients didn't receive any other disease modifying treatment after discontinuing natalizumab.
  
  
  RESULTS
  A total of 27 patients with very active RRMS before natalizumab start (mean annualized relapse rate of 2.3, MRI activity in 21 of 27 patients) were studied. Within 6 months after discontinuing natalizumab, 18 patients (67%) experienced clinical relapse and 3 additional patients had radiological activity, without clinical relapse. Four patients (15%) experienced a rebound activity, with severe relapse and 20 or more gadolinium enhancing lesions on MRI.
  
  
  CONCLUSIONS
  Such observational data didn't support the concept of drug holiday when using natalizumab in very active RRMS.
authors.affiliation: Service de neurologie, CIC-P 0203 INSERM, centre hospitalier universitaire, Rennes, France.
authors.forename: A
authors.initials: A
authors.lastname: Kerbrat
authors.forename: E
authors.initials: E
authors.lastname: Le Page
authors.forename: E
authors.initials: E
authors.lastname: Leray
authors.forename: T
authors.initials: T
authors.lastname: Anani
authors.forename: M
authors.initials: M
authors.lastname: Coustans
authors.forename: C
authors.initials: C
authors.lastname: Desormeaux
authors.forename: C
authors.initials: C
authors.lastname: Guiziou
authors.forename: P
authors.initials: P
authors.lastname: Kassiotis
authors.forename: F
authors.initials: F
authors.lastname: Lallement
authors.forename: D
authors.initials: D
authors.lastname: Laplaud
authors.forename: P
authors.initials: P
authors.lastname: Diraison
authors.forename: F
authors.initials: F
authors.lastname: Rouhart
authors.forename: E
authors.initials: E
authors.lastname: Sartori
authors.forename: R
authors.initials: R
authors.lastname: Wardi
authors.forename: S
authors.initials: S
authors.lastname: Wiertlewski
authors.forename: G
authors.initials: G
authors.lastname: Edan
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000188:drug therapy* / Q000453:epidemiology / Q000503:physiopathology; D000069442:Natalizumab; D012189:Retrospective Studies; D055502:Secondary Prevention; D013997:Time Factors; D055815:Young Adult
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000069442:Natalizumab