title: Scintigraphic detection of TNF-driven inflammation by radiolabelled certolizumab pegol in patients with rheumatoid arthritis and spondyloarthritis.
abstract: BACKGROUND
  Biologicals are the cornerstone for many treatment algorithms in inflammatory arthritis. While tumour necrosis factor (TNF) inhibitors may achieve important responses in ∼50% of patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA), a significant fraction of patients are partial or non-responders. We hypothesised that in vivo assessment of TNF by scintigraphy with 99mTc-radiolabelled certolizumab pegol (CZP) might lead to a more 'evidence-based biological therapy'.
  
  
  OBJECTIVE
  Our goal was to perform a proof-of-concept study of in vivo detection of TNF by immunoscintigraphy of a radiolabelled TNF inhibitor in RA and SpA, and correlate this with clinical, imaging findings and therapeutic outcome.
  
  
  METHODS
  CZP was conjugated with succinimidyl-6-hydrazino-nicotinamide and subsequently radiolabelled with Tc99m. Whole body and static images of hands, feet and sacroiliac joints of 20 patients (5 RA; 15 SpA) were acquired at 3 time points. Immunoscintigraphic findings were scored semiquantitatively. Subsequently, all patients were treated with CZP.
  
  
  RESULTS
  In peripheral joints, clinically affected joints or abnormal ultrasound findings were observed more frequently (p<0.001) in the scintigraphic-positive group. In patients with axial SpA, bone marrow edema on MRI was detected more frequently (p<0.001) in quadrants with tracer uptake. At the patient level, the odds of a joint remaining tender despite 24 weeks of CZP treatment was significantly smaller in joints with clear tracer uptake as compared with those with no uptake (OR=0.42, p=0.04).
  
  
  CONCLUSIONS
  Immunoscintigraphy with radiolabelled CZP demonstrated both axial and peripheral inflammation, and displayed good correlation with clinical features, conventional imaging and therapy response.
  
  
  BACKGROUND
  NCT01590966; Results.
authors.affiliation: Department of Rheumatology , Ghent University Hospital , Ghent , Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Carron
authors.affiliation: Department of Nuclear Medicine , Ghent University Hospital , Ghent , Belgium.
authors.forename: Bieke
authors.initials: B
authors.lastname: Lambert
authors.affiliation: Department of Rheumatology , Ghent University Hospital , Ghent , Belgium.
authors.forename: Liesbet
authors.initials: L
authors.lastname: Van Praet
authors.affiliation: Department of Radiopharmacy , Ghent University , Ghent , Belgium.
authors.forename: Filip
authors.initials: F
authors.lastname: De Vos
authors.affiliation: Department of Rheumatology, Ghent University Hospital, Ghent, Belgium; VIB Inflammation Research Center, Ghent University, Ghent, Belgium.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Varkas
authors.affiliation: Department of Radiology , Ghent University Hospital , Ghent , Belgium.
authors.forename: Lennart
authors.initials: L
authors.lastname: Jans
authors.affiliation: Department of Rheumatology, Ghent University Hospital, Ghent, Belgium; VIB Inflammation Research Center, Ghent University, Ghent, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: Elewaut
authors.affiliation: Department of Rheumatology , Ghent University Hospital , Ghent , Belgium.
authors.forename: Filip
authors.initials: F
authors.lastname: Van den Bosch
keywords: Magnetic Resonance Imaging; Rheumatoid Arthritis; Spondyloarthritis; TNF-alpha; Ultrasonography