Slowing of disease progression in rheumatoid arthritis patients during long-term treatment with leflunomide or sulfasalazine

Radiographic disease progression with leflunomide and sulfasalazine treatment was assessed in rheumatoid arthritis patients in a double-blind trial that was placebo controlled for the first 6 months. Completers at 6 months opted to continue on 12- and 24-month double-blind extensions; patients in the placebo group were switched to sulfasalazine. Changes in Larsen scores were assessed in evaluable patient cohorts at 6 (n=228), 12 (n=136), and 24 (n=65) months. Changes in Larsen scores and erosive joint counts with leflunomide and sulfasalazine at 6 months showed significantly less radiographic progression than placebo. Sustained retardation of radiographic progression was seen in the 24-month intent-to-treat cohorts (delta Larsen scores: leflunomide -0.07, sulfasalazine -0.03). Changes in erosive joint counts within the 24-month leflunomide cohort suggest halting of disease progression for patients who continued in the study for 2 years (leflunomide -0.92, sulfasalazine 0.80). Leflunomide was well tolerated with no unexpected adverse events during the 2-year period. This study demonstrates that slowing of disease progression with leflunomide, observed as early as 6 months, is maintained long term in patients who complete 2 years of treatment.