We previously reported that the new disease modifying antirheumatic drug leflunomide resulted in significant improvement in functional ability compared with placebo and sulfasalazine in a 6 month double blind, randomized, Phase III trial in rheumatoid arthritis (RA). The current study compared functional disability in cohorts of patients with RA from the initial study who volunteered to continue treatment with leflunomide or sulfasalazine.
The Health Assessment Questionnaire (HAQ) was used to assess functional ability in patients completing 6 months of therapy who chose to continue in double blinded 12 and 24 month extensions. Patients on active regimens continued taking leflunomide 20 mg/day or sulfasalazine 2 g/day; those taking placebo were switched at Month 6 to sulfasalazine.
Leflunomide significantly improved patients' functional ability compared to placebo (p < or = 0.0001) and sulfasalazine (p < or = 0.01) at 6 months. These changes were seen as early as Month 1, and continued improvements were seen in 12 and 24 month cohorts. Mean HAQ scores were significantly improved with leflunomide compared with sulfasalazine at 24 months (-0.65 vs -0.36; p = 0.0149); corresponding changes in HAQ Disability Index (DI) were -0.73 vs -0.56 and were not statistically different. Leflunomide is safe and well tolerated and no unexpected adverse events were noted during the 2 year period; diarrhea, nausea, and alopecia were less frequent with continued treatment.
These longterm data confirm leflunomide improves functional ability as shown by reductions in HAQ scores. The benefit of leflunomide is reflected in other efficacy criteria, such as global assessments and the American College of Rheumatology response rates, all of which showed significantly more improvement with leflunomide than sulfasalazine at 24 months.