To examine the potential therapeutic effects of leflunomide in patients with active AS in an open label study.
Twenty patients with AS fulfilling the 1984 modified New York criteria with a Bath AS Disease Activity Index (BASDAI) >3 were given leflunomide for 6 months. Clinical outcome assessments included disease activity (BASDAI), function (BASFI), metrology (BASMI), patient's and physician's global assessment, peripheral joint assessment, quality of life (SF-36), global pain, and CRP. Primary end point was a reduction of disease activity as measured by the BASDAI of >25% at 6 months.
A BASDAI 25% improvement was noted in 5/20 (25%) patients and a BASDAI 50% improvement in 4/20 (20%) patients. The absolute BASDAI did not change significantly over the 6 month study (4.9 at baseline v 4.3 at week 24, p>0.05). Similarly, no significant change was found for the BASFI, BASMI, patient's and physician's global assessment, SF-36 mental component, and CRP. For the 10 patients with peripheral arthritis, the mean number of inflamed joints was significantly reduced from 1.7 at baseline to 0.9 at week 12 (p = 0.034) and 0.2 at week 24 (p = 0.039).
In this open study of patients with active AS only those with peripheral arthritis improved significantly with leflunomide treatment. Axial symptoms did not improve.