title: Progression of structural damage is not related to rituximab serum levels in rheumatoid arthritis patients.
abstract: OBJECTIVE
  The most cost-effective dosing regimen for rituximab treatment in RA is currently unknown. The objective of this study is to determine whether low rituximab serum levels are associated with progression of structural damage in RA patients.
  
  
  METHODS
  Sixty-two RA patients were treated with rituximab in three different centres. Structural damage was assessed on radiographs of hands and feet before and 1 year after therapy using the Sharp-van der Heijde scoring method (SHS). Patients were divided into progressors vs non-progressors based on different cut-off values. Rituximab serum levels were measured by sandwich ELISA after 4 and 12 weeks (Leiden University Medical Center and University Medical Centre, Utrecht cohorts) or 4 and 16 weeks (Academic Medical Center/University of Amsterdam cohort).
  
  
  RESULTS
  There was no difference in rituximab levels between progressors and non-progressors 4 weeks and 12 or 16 weeks after initiation of treatment in the different cohorts. There was also no correlation between rituximab levels at week 4 or week 12 or 16 and change in SHS score after 1 year.
  
  
  CONCLUSIONS
  Low rituximab serum levels are not associated with progression of structural damage in RA patients. The results do not support the use of dosages higher than 2 × 1000 mg rituximab to inhibit progression of joint destruction.
authors.affiliation: Division of Clinical Immunology and Rheumatology, Academic Medical Center/University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Maria
authors.initials: M
authors.lastname: Boumans
authors.forename: Onno
authors.initials: O
authors.lastname: Teng
authors.forename: Rogier
authors.initials: R
authors.lastname: Thurlings
authors.forename: Johannes
authors.initials: J
authors.lastname: Bijlsma
authors.forename: Danielle
authors.initials: D
authors.lastname: Gerlag
authors.forename: Tom
authors.initials: T
authors.lastname: Huizinga
authors.forename: Koen
authors.initials: K
authors.lastname: Vos
authors.forename: Steven
authors.initials: S
authors.lastname: Stapel
authors.forename: Gertjan
authors.initials: G
authors.lastname: Wolbink
authors.forename: Janneke
authors.initials: J
authors.lastname: Tekstra
authors.forename: Jaap
authors.initials: J
authors.lastname: van Laar
authors.forename: Paul P
authors.initials: PP
authors.lastname: Tak
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D058846:Antibodies, Monoclonal, Murine-Derived / Q000008:administration & dosage* / Q000097:blood*; D018501:Antirheumatic Agents / Q000008:administration & dosage / Q000097:blood; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D001175:Arthrography / Q000379:methods; D015331:Cohort Studies; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005528:Foot / Q000000981:diagnostic imaging; D006225:Hand / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D000069283:Rituximab; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D055815:Young Adult
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D018501:Antirheumatic Agents; D000069283:Rituximab
keywords: B cells; biologics; radiology; rheumatoid arthritis; rituximab