It has been reported that antibodies to oral anaerobic bacteria are elevated in the serum and synovial fluids of patients with rheumatoid arthritis. Macrolide antibiotics are active against oral anaerobic bacteria.
The aim of this work was to evaluate the clinical efficacy of roxithromycin in patients with early seropositive rheumatoid arthritis.
This was a double-blind trial. We enrolled adult patients with early rheumatoid arthritis who had not previously received disease-modifying antirheumatic drugs and randomized them to receive either once-daily oral roxithromycin 300 mg or once-daily oral placebo for 3 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 ACR 20 response) at 3 months. Secondary outcome measures were 50% improvement and 70% improvement according to ACR criteria (an ACR 50 response and an ACR 70 response, respectively). The 28-joint disease activity score (DAS28) was also calculated. Clinical remission was defined as DAS28 score <2.6, and a low level of disease activity was defined as DAS28 score <3.2 but > or =2.6. Adverse event data (eg, example, type, severity, time of occurrence, time to resolution) were obtained from physical examinations and patient self-reporting.
The roxithromycin group had 16 patients (mean [SD] age, 45  years; 11 women, 5 men; all white). The placebo group had 15 patients (mean [SD] age, 42  years; 10 women, 5 men; all white). A significantly greater percentage of patients treated with 300 mg of roxithromycin experienced an ACR 20 re- sponse at 3 months, compared with those who received placebo (75% [n = 12] vs 20% [n = 3]; P = 0.002). Greater percentages of patients treated with 300 mg of roxithromycin also achieved ACR 50 responses (56% [n = 9] vs 7% [n = 1]; P = 0.003) and ACR 70 responses (44% [n = 7] vs 0%; P = 0.004) compared with patients who received placebo. At month 3, DAS28 response rates were significantly greater with once-daily roxithromycin 300 mg than with once-daily placebo (P < 0.001). Adverse events were reported for 11 patients (69%) in the roxithromycin group and 7 patients (47%) in the placebo group. The most common adverse events (>5%) were nausea, abdominal pain, headache, and dry mouth. There were no dose-limiting toxic effects. One participant in the roxithromycin group withdrew from the study because of severe emesis; two withdrew from the placebo group because of lack of efficacy.
In these adult patients with rheumatoid arthritis, 3-month treatment with roxithromycin significantly improved the signs and symptoms of rheumatoid arthritis and was generally well tolerated. Future studies should investigate the relationship between disease activity and serum or joint antibodies to anaerobic bacteria.