Methotrexate analogues display enhanced inhibition of TNF-α production in whole blood from RA patients.

Objectives: 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.Method: T cells in whole blood from 18 RA patients (including MTX-naive, 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, P...