Objective: To determine if patients with rheumatoid arthritis (RA) that is stable with weekly methotrexate (MTX) therapy could be switched to an every-other-week regimen of MTX.
Methods: Forty-seven patients with classic or definite RA who had received MTX for at least 8 months were studied. Clinical measurements consisted of the number of tender and swollen joints, physician and patient global evaluation of disease activity on a 5-point scale, grip strength, patient evaluation of pain, morning stiffness, and the interval to onset of fatigue from time of awakening. Laboratory measures included the erythrocyte sedimentation rate (ESR), rheumatoid factor, C-reactive protein (CRP), and baseline serum folate levels. Uptake of MTX was measured with tritiated thymidine from peripheral blood mononuclear cells (PBMC) from patients ex vivo. Serum measures of interleukin-1 beta (IL-1 beta), IL-6, and tumor necrosis factor alpha (TNF alpha) were performed in sera, and TNF alpha was also measured on PBMC supernatants.
Results: Twelve of the 23 patients receiving every-other-week MTX (52%) were able to complete 6 months of this treatment without experiencing a disease flare. Eleven of the 23 patients receiving every-other-week MTX (48%) withdrew from the study before completing 6 months of treatment, because of a flare. No significant differences in clinical or laboratory parameters were seen when the 24 patients receiving weekly MTX were compared with the 12 patients in the every-other-week MTX group who successfully completed 6 months of the study. None of the changes in serum cytokine levels were significantly different between the patients receiving MTX weekly versus those receiving it every other week, and changes in ESR and CRP did not differ between groups. Age, sex, RA disease duration, MTX weekly dose or duration, baseline joint counts, or serum folate status did not predict a flare. Tritiated MTX uptake did not differ between groups.
Conclusion: Some patients with RA that is stable on weekly dosing are able to change to every-other-week dosing without experiencing a flare in their disease activity.