Objective: To investigate whether there is interaction between chloroquine and cyclosporine (CyA) at the level of efficacy and toxicity in patients with recent onset rheumatoid arthritis (RA).
Methods: Eighty-eight patients with recent onset RA, who had shown a suboptimal clinical response on low dose chloroquine monotherapy, were randomly assigned to additional treatment with placebo, CyA 1.25 mg/kg/day, or CyA 2.50 mg/kg/day (fixed doses) for another 24 weeks. The tender joint count was the primary outcome assessment of efficacy and the serum creatinine of toxicity. The 1995 preliminary ACR response criteria for improvement were applied to evaluate individual clinical responses.
Results: Two patients in the placebo group (n = 29), 7 patients in the CyA 1.25 mg group (n = 29), and 8 patients in the CyA 2.50 mg group (n = 30) (p = 0.06) discontinued study medication prematurely for inefficacy or adverse events. The intention-to-treat analysis revealed that the tender joint count decreased 2.2 +/- 6.1 (mean +/- SD) joints in the placebo group, 2.2 +/- 6.6 joints in the CyA 1.25 mg group, and 5.0 +/- 5.8 joints in the CyA 2.50 mg group (p = 0.04). The 1995 preliminary ACR response criteria for clinical improvement were met by 8 (28%) patients in the placebo group, 10 (34%) patients in the CyA 1.25 mg group, and 15 (50%) patients in the CyA 2.50 mg group (p = 0.07). The serum creatinine increased 2 +/- 7 micromol/l in the placebo group, decreased 1 +/- 8 micromol/l in the CyA 1.25 mg group, and increased 10 +/- 15 micromol/l in the CyA 2.50 mg group (p < 0.001).
Conclusion: The addition of low dose CyA is moderately effective in patients with early RA already treated with low dose chloroquine, but results in statistically significant renal function loss.