Assessment of disease activity in rheumatoid arthritis using a novel folate targeted radiopharmaceutical Folatescan TM

E. L. Matteson, V. J. Lowe, F. G. Prendergast, C. S. Crowson, K. G. Moder, D. E. Morgenstern, R. A. Messmann, P. S. Low

Research output: Contribution to journalArticle

57 Scopus citations

Abstract

Development of a simple and accurate technique for detecting active inflammation in the joints and other tissues of patients with inflammatory disorders is an unmet need in rheumatic diseases. This study is a preliminary assessment of the safety and usage of a radiopharmaceutical, FolateScan TM (Technetium-99m EC20; 99mTc-EC20), for detecting disease activity in patients with rheumatoid arthritis. Methods EC2O is afolate-targeted diagnostic radiopharmaceutical which binds to the folate receptor and is preferentially taken up by activated macrophages. In this open-label, cross-sectional study, a total of 40 patients with RA (26 with one or more swollen joints, 14 with clinically quiescent joint disease; 0/66 joint count) as well as 6 patients with osteoarthritis, 12 patients with other inflammatory conditions and 5 healthy subjects received 0.1 mg of EC2O labeled with 20-25mCi of technetium-99m. Disease activity was scored in each joint and other target tissues by a radiologist blinded to the clinical assessment, and results were compared to the rheumatologist physical examination, which served as the test standard. The 40 patients (78% female) with RA had a mean age of 56.9 years. Assessment of uptake of 99mTc-EC2O in joints of patients with RA based on image analysis was compared to the clinical examination. FolateScan detected more actively involved joints in 27 patients (68%) than joints recorded as "swollen", and more actively involved joints in 25 patients (63%) than joints recorded as "painful and/or swollen". The number of swollen joints by clinical exam was correlated with ESR (r=0.43; p=O.OOi5) and C-rp (r=0.35; p =0.03). The number of actively involved joints by Folate Scan was also correlated with ESR (r=0.47; p =0.002) and C-rp (r=0.36; p =0.02). Joint uptake was also seen in patients with osteoarthritis. FolateScan is a potentially useful tool for detection of disease activity in patients with RA and may be more sensitive than the physical examination.

Original languageEnglish (US)
Pages (from-to)253-259
Number of pages7
JournalClinical and experimental rheumatology
Volume27
Issue number2
StatePublished - Mar 1 2009

Keywords

  • Folate receptor
  • FolateScan
  • Radiopharmaceutical
  • Rheumatoid arthritis

ASJC Scopus subject areas

  • Rheumatology
  • Immunology and Allergy
  • Immunology

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