We conducted a preliminary study to evaluate the efficacy and safety of FK 506 for rheumatoid arthritis (RA) patients. Subjects were 29 RA patients in an active state. The trial was of an open, uncontrolled design, with a comparison of 2 treatment schedules. An intermittent administration group, 11 patients, received biweekly doses of 5 mg/time for 4 weeks, 7 mg/time for next 4 weeks and then 9mg/time for 16 weeks. A daily administration group, 18 patients, received doses of 3mg/day for 4 weeks, 4mg/day for next 4 weeks and then 5 mg/day for 16 weeks. The clinical efficacy was assessed by numbers of swollen and tender joints, morning stiffness, grip strength, ESR, CRP, rheumatoid factor, Lansbury index and ADL. Moderate to marked improvement on the final global assessment was obtained in 36.4% of the patients in the intermittent administration group and in 76.5% of the patients in the daily administration group. BSR and CRP were significantly decreased by the 4th or 8th week of treatment in the daily administration group, but not in the intermittent administration group. Adverse events were mainly gastrointestinal symptoms, cardiovascular symptoms, increased serum levels of BUN, uric acid, glucose and creatinine. In the daily administration group, 1 of 7 patients who received 3mg/day during the trial without increasing doses and 5 of 11 patients who received 4-5mg/day showed the elevation of 0.3mg/dl or more in the serum level of creatinine. Daily administration of F 506 at the dose of 3mg/day or less might have a salutary therapeutic effect on RA patients.
