Rheumatoid arthritis treated with tenidap and piroxicam. Clinical associations with cytokine modulation by tenidap.

Objective: To compare the effects of tenidap and piroxicam on acute-phase protein and cytokine levels in the blood of rheumatoid arthritis (RA) patients and to explore their associations with clinical disease activity.

Methods: A double-blind, randomized, crossover trial in 49 patients with active RA compared 6 weeks of treatment with tenidap (120 mg/day) versus 6 weeks of treatment with piroxicam (20 mg/day).

Results: Median values for C-reactive protein (CRP), Westergren erythrocyte sedimentation rate (ESR), serum amyloid A (SAA) protein, and interleukin-6 (IL-6) were significantly lower after tenidap treatment compared with piroxicam treatment, even in the presence of stable background treatment with prednisone, methotrexate, or prednisone plus methotrexate. The median within-patient treatment differences (after tenidap minus after piroxicam) in the CRP, ESR, SAA, and IL-6 values were -1.7 mg/dl, -10.0 mm/hour, -22.0 micrograms/ml, and -3.7 pg/ml, respectively, and represent -60.4%, -17.7%, -35.5%, and -26.1% of the respective baseline levels. IL-6 levels were positively correlated with CRP and SAA. Plasma IL-1 beta was generally below the level of detection. Tumor necrosis factor alpha levels were similar after tenidap and after piroxicam. Treatment differences for 4 of 7 clinical parameters favored tenidap, but did not reach statistical significance. IL-6, CRP, and ESR were significantly correlated with clinical treatment differences. Tenidap and piroxicam toleration were similar, although tenidap-treated patients exhibited a reversible increase in urinary protein excretion.

Conclusions: Tenidap was differentiated from piroxicam by lower levels of acute-phase proteins, ESR, and IL-6 after tenidap treatment. These treatment differences were significantly correlated with clinical parameters.