Treatment of rheumatoid arthritis with roxithromycin: a randomized trial.

High levels of antibodies to oral anaerobic bacteria have been found in the serum and synovial fluid of patients with rheumatoid arthritis (RA). Macrolide antibiotics are active against oral anaerobic bacteria. The aim of this trial was to evaluate the efficacy of roxithromycin in patients with RA who had not responded to disease-modifying antirheumatic drugs. This was a 6-month, randomized, double-blind, placebo-controlled trial. We treated 100 patients with active RA with either once-daily oral roxithromycin 300 mg or daily oral placebo for 6 months. The primary efficacy variable was the percentage of patients who had a 20% improvement according to the American College of Rheumatology (ACR) criteria (an ACR20 response) at 6 months. Secondary outcome measures were 50% improvement and 70% improvement according to ACR criteria (an ACR50 response and an ACR70 response, respectively). A significantly greater percentage of patients treated with roxithromycin 300 mg met the ACR 20% improvement criteria (ie, achieved an ACR20 response) at 6 months compared with patients who received placebo (60% vs 34%; P = 0.009). Greater percentages of patients treated with roxithromycin 300 mg also achieved ACR50 responses (38% vs 12%; P = 0.003) and ACR70 responses (18% vs 2%; P = 0.008) compared with patients who received placebo. Roxithromycin was well tolerated, with an overall safety profile similar to that of placebo. In patients with active RA, treatment with roxithromycin significantly improved the signs and symptoms of RA.