No abstract

No abstract

Ten patients with rheumatoid arthritis (RA) were evaluated in a placebo-controlled, double-blind study examining the clinical efficacy of a novel nonsteroidal anti-inflammatory agent: Tenidap (CP-66,248). RA patients receiving active drug therapy (n = 6) demonstrated clinically significant improvements in observer assessment of pain (p less than 0.025), painful joint count (p less than 0.010), and overall clinical assessment as based on a modified rheumatoid activity index, MRAI (p less than 0.025). In parallel laboratory assays, Tenidap was found to exhibit a significant in vitro dose-dependent inhibition of ionophore-stimulated neutrophil production of the 5-lipoxygenase product: [3H]leukotriene B4 (LTB4). Although more importantly, Tenidap was also found to exhibit an in vitro dose-dependent inhibition (IC50 20 microM) of the ionophore-stimulated release (deacylation) of the precursor [3H]arachidonic acid (AA) from membrane phospholipids. In further studies, Tenidap did not have any effect on fMLP-induced neutrophil chemotactic response. These results suggest that one of the possible mechanisms for the clinical effectiveness of this agent, may be through its effect at inhibiting the release of free AA from membrane phospholipids and therefore limiting its further metabolism into certain biologically-active inflammatory lipids.

A recently reported technique employing the leukotactic index which represents all migrating cells in in vitro neutrophil chemotaxis systems, was compared to the leading front technique for assaying antirheumatic drug effects on this important neutrophil function. Normal human neutrophils were treated with therapeutic concentrations of aspirin, gold sodium thiomalate, mpenicillamine, and azathioprine. The responses of these cells and of control cells to neutrophil-immune complex-serumderived chemotactic factors were assayed in Boyden chambers. Significant (P < 0.05) inhibition was observed by the leading front technique only for mpenicillamine at high concentrations. Significant (P < 0.01) inhibition was seen with mpenicillamine at therapeutic plasma levels with the leukotactic index technique. Gold sodium thiomalate and aspirin at high concentrations also produced significant (P < 0.01 and P < 0.05) inhibition of chemotaxis as assayed by the leukotactic index procedure. Azathioprine had no significant effects when studied with either technique. These results indicate that the leukotactic index may be a more sensitive technique for quantitating neutrophil migration in response to chemotactic factors and may therefore provide useful additional information for determining the effects of antirheumatic drugs on this important neutrophil function. 200