title: Methotrexate analogues display enhanced inhibition of TNF-α production in whole blood from RA patients.
abstract: OBJECTIVE
  Although methotrexate (MTX) is the anchor drug in the treatment of rheumatoid arthritis (RA), patients experience clinical resistance to MTX upon prolonged treatment. We explored whether new-generation antifolates elicit superior anti-inflammatory properties when compared to MTX, based on their capacity to inhibit tumour necrosis factor (TNF)-α production.
  
  
  METHODS
  T cells in whole blood from 18 RA patients (including MTX-naïve, MTX- responsive, and MTX non-responsive patients) and seven healthy volunteers were stimulated with αCD3/αCD28 antibodies and incubated ex vivo for 72 h with MTX and eight novel antifolate drugs with potentially favourable biochemical and pharmacological properties. Drug concentrations exerting 50% inhibition (IC-50) of TNF-α production (by enzyme-linked immunosorbent assay, ELISA) were determined as an estimate for their anti-inflammatory capacity. In addition, induction of T-cell apoptosis was evaluated by flow cytometry.
  
  
  RESULTS
  The new-generation antifolates PT523, PT644, raltitrexed, and GW1843 proved to be potent inhibitors of TNF-α production in activated T cells from all three groups of RA patients and from healthy volunteers. Based on IC-50 values, these antifolates were up to 10.3 times more potent than MTX. The anti-inflammatory effects were observed at drug concentrations that provoked suppression of T-cell activation and induction of apoptosis in 20-40% of activated T cells.
  
  
  CONCLUSIONS
  In an ex-vivo setting, novel antifolates elicited marked inhibition of TNF-α production in activated T cells from RA patients. Further clinical evaluation is warranted to investigate whether a low dosage of these antifolates can elicit immunosuppressive effects equivalent to MTX, and whether they are superior to MTX in patients who fail to respond to MTX.
authors.affiliation: Department of Rheumatology, VU University Medical Center , Amsterdam , The Netherlands.
authors.forename: J W
authors.initials: JW
authors.lastname: van der Heijden
authors.forename: Y G
authors.initials: YG
authors.lastname: Assaraf
authors.forename: A H
authors.initials: AH
authors.lastname: Gerards
authors.forename: R
authors.initials: R
authors.lastname: Oerlemans
authors.forename: W F
authors.initials: WF
authors.lastname: Lems
authors.forename: R J
authors.initials: RJ
authors.lastname: Scheper
authors.forename: B A C
authors.initials: BA
authors.lastname: Dijkmans
authors.forename: G
authors.initials: G
authors.lastname: Jansen
mesh_terms: D018501:Antirheumatic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism; D005260:Female; D005493:Folic Acid Antagonists / Q000494:pharmacology; D006801:Humans; D008297:Male; D008727:Methotrexate / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D008875:Middle Aged; D009952:Ornithine / Q000031:analogs & derivatives / Q000494:pharmacology; D011622:Pterins / Q000494:pharmacology; D011799:Quinazolines / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D013876:Thiophenes / Q000494:pharmacology; D016597:Trimetrexate / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis*
chemical_list: D018501:Antirheumatic Agents; D005493:Folic Acid Antagonists; D011622:Pterins; D011799:Quinazolines; D013876:Thiophenes; D014409:Tumor Necrosis Factor-alpha; C085590:N(alpha)-(4-amino-4-deoxypteroyl)-N(delta)-hemiphthaloyl-L-ornithine; D009952:Ornithine; C068874:raltitrexed; D016597:Trimetrexate; D008727:Methotrexate