title: Evaluation of tocilizumab therapy in patients with rheumatoid arthritis based on FDG-PET/CT.
abstract: BACKGROUND
  Positron emission tomography (PET) with 2-[18F]-fluoro-2-deoxy-D-glucose (18F-FDG) can detect the presence of synovitis in rheumatoid arthritis (RA) patients. The aim of this study was to investigate whether the findings of FDG-PET matched the conventional assessments of the disease activity score (DAS) 28, DAS28-CRP, simplified disease activity index (SDAI) and clinical disease activity index (CDAI) in RA patients receiving tocilizumab (TCZ) therapy.
  
  
  METHODS
  Seventeen RA patients treated with TCZ were assessed. FDG-PET was performed at baseline and three and six months after the initiation of TCZ therapy. The maximum SUV (SUVmax) of the bilateral shoulder, elbow, wrist, hip, knee and ankle joints were added together (total SUV) and were used to assess the degree of FDG uptake as a representative parameter. The correlations between the ΔSUV and the difference in the clinical parameters at baseline and at each observation period, and the differences in each clinical parameters, were assessed.
  
  
  RESULTS
  The ΔSUV, the differences in the total SUV at baseline and at three/six months after starting treatment positively correlated with the ΔDAS28 (r = 0.615 p = 0.009/ r = 0.775 p < 0.001), ΔDAS28-CRP (r = 0.696, p = 0.002/ r = 0.828, p < 0.001), ΔSDAI (r = 0.652, p = 0.005/ r = 0.686, p = 0.002) and ΔCDAI (r = 0.662, p = 0.004/ r = 0.711, p = 0.001) for each period. The total SUV was significantly decreased at three and six months after the initiation of TCZ (p < 0.05).
  
  
  CONCLUSIONS
  A reduction in the FDG uptake was observed at three and six months after the initiation of TCZ therapy. The disease activity estimated on FDG-PET/CT matched the conventional parameters following the TCZ therapy in RA patients.
authors.affiliation: Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, 3-39-22, Showamachi, Maebashi, Gunma 371-8511, Japan. kokamura@gunma-u.ac.jp.
authors.forename: Koichi
authors.initials: K
authors.lastname: Okamura
authors.forename: Yukio
authors.initials: Y
authors.lastname: Yonemoto
authors.forename: Chisa
authors.initials: C
authors.lastname: Okura
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Higuchi
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Tsushima
authors.forename: Kenji
authors.initials: K
authors.lastname: Takagishi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000188:drug therapy*; D004341:Drug Evaluation / Q000379:methods; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D019788:Fluorodeoxyglucose F18; C502936:tocilizumab