Objective: To determine if tacrolimus (FK506) has potential as a therapeutic agent in patients with severe and/or refractory rheumatoid arthritis (RA).
Methods: Twelve patients with RA who had severe and active disease and had failed an average of 5.3 disease modifying antirheumatic drugs (DMARD) were treated with tacrolimus 2-6 mg/day in an open label study. Patients were assessed monthly with respect to RA outcomes and drug related toxicities.
Results: Of the 12 patients, 7 were able to complete 6 months of treatment. In these 7 patients, significant improvements were seen in tender joint count (from 26.4 +/- 4.2 to 11.7 +/- 3.2; p = 0.007), swollen joint count (from 17.7 +/- 2.5 to 4.1 +/- 1.3; p = 0.001), and other RA outcomes. All 7 patients achieved the 20% response criteria of the American College of Rheumatology (ACR), and 5 of 7 patients met the ACR 50% response criteria. The other 5 patients withdrew in the first 3 months of treatment due to gastrointestinal symptoms (3), chest pain (1), and neuropathic pain (1). Serum creatinine levels were unchanged in all patients, and hypertension was not seen.
Conclusion: Tacrolimus was tolerated by only 7 of 12 patients, but in 5 of these 7 patients with severe and refractory disease, the clinical responses were very good.