Value of 18F-FDG PET/CT for therapeutic assessment of patients with polymyalgia rheumatica receiving tocilizumab as first-line treatment
- 731 Downloads
To evaluate the use of 18F-FDG PET/CT for the assessment of tocilizumab (TCZ) as first-line treatment in patients with polymyalgia rheumatica (PMR).
Patients with PMR were prospectively enrolled in a multicentre clinical trial assessing TCZ therapy (the TENOR trial). The patients underwent FDG PET/CT at baseline, after the first infusion of TCZ (TCZ 1) and after the last infusion of TCZ (TCZ 3). Responses to treatment were evaluated in terms of the PMR activity score (PMR-AS), and the C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) laboratory tests. Maximal standardized uptake value (SUVmax) was used for assessment of FDG uptake in regions usually affected in PMR (spinous processes, hips, shoulders, sternoclavicular region and ischial tuberosities). The Wilcoxon test was applied to evaluate the changes in parameters after the infusions and Spearman’s rank correlation test was applied to assess the correlations between SUVmax and PMR-AS, CRP and ESR.
Of 21 patients included in the trial, 18 were evaluated. The median bioclinical parameter values decreased after TCZ 1 (PMR-AS from 38.2 to 15.7, CRP from 65.2 to 0.4 mg/l and ESR from 49 to 6.5 mm; all p < 0.05) as did the median SUVmax (from 5.8 to 5.2; p < 0.05). All values also decreased after TCZ 3 (PMR-AS from 38.2 to 3.9, CRP from 65.2 to 0.2, ESR from 49 to 2, and SUVmax from 5.8 to 4.7; p < 0.05). In a region-based analysis, all SUVmax were significantly reduced after TCZ 3, except the values for the cervical spinous processes and shoulder regions. With regard to correlations, few significant differences were found between ∆SUVmax and the other parameters including ∆PMR-AS, ∆CRP and ∆ESR in the patient-based and region-based analysis.
FDG uptake decreased significantly but moderately after TCZ therapy in PMR patients, and might reflect disease activity.
Keywords18F-FDG PET/CT Polymyalgia rheumatica Cytokines Inflammation Therapeutic assessment
Compliance with ethical standards
Roche-Chugai provided an unconditional grant for the study. Tocilizumab was donated free of charge by Roche-Chugai. Roche-Chugai had no role in the design or conduct of the study, or the management of the collection, analysis or interpretation of the data, or in the preparation, revision or approval of the manuscript.
Conflicts of interest
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the principles of the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.
Written informed consent was obtained from all individual participants included in the study.
- 22.Yamashita H, Kubota K, Takahashi Y, Minamimoto R, Morooka M, Kaneko H, et al. Similarities and differences in fluorodeoxyglucose positron emission tomography/computed tomography findings in spondyloarthropathy, polymyalgia rheumatica and rheumatoid arthritis. Joint Bone Spine. 2013;80:171–7.CrossRefPubMedGoogle Scholar
- 23.Yamashita H, Kubota K, Takahashi Y, Minaminoto R, Morooka M, Ito K, et al. Whole-body fluorodeoxyglucose positron emission tomography/computed tomography in patients with active polymyalgia rheumatica: evidence for distinctive bursitis and large-vessel vasculitis. Mod Rheumatol. 2012;22:705–11.CrossRefPubMedGoogle Scholar
- 30.Kanstrup IL, Klausen TL, Bojsen-Møller J, Magnusson P, Zerahn B. Variability and reproducibility of hepatic FDG uptake measured as SUV as well as tissue-to-blood background ratio using positron emission tomography in healthy humans. Clin Physiol Funct Imaging. 2009;29(2):108–13.CrossRefPubMedGoogle Scholar