OBJECTIVE Recent studies have demonstrated the short term efficacy of leflunomide. This study evaluates the efficacy and safety of leflunomide and sulfasalazine in rheumatoid arthritis over a two year follow up period.

RESULTS The efficacy seen at six months was maintained at 12 and 24 months. Twenty four month cohorts on leflunomide showed significant improvement compared with sulfasalazine in doctor (−1.46 v−1.11, p=0.03) and patient (−1.61 v−1.04, p<0.001) global assessments, ACR20% response (82%v 60%, p<0.01), and functional ability (Δmean HAQ −0.65 v −0.36, p=0.0149; ΔHAQ disability index −0.89 v −0.60, p=0.059). Improvement in other variables was comparable for the two drugs, including slowing of disease progression. Improved HAQ scores in 6, 12, and 24 month leflunomide cohorts were seen in both non-responders (24%, 29%, 35%, respectivelyv sulfasalazine 8%, 10%, 27%) and ACR20% responders (leflunomide 63%, 62%, 66% vsulfasalazine 50%, 64%, 44%). Leflunomide is well tolerated at doses of 20 mg. No unexpected adverse events or late toxicity were noted during the two year period. Diarrhoea, nausea, and alopecia were less frequent with continued treatment.

CONCLUSION These long term data confirm that leflunomide is an efficacious and safe disease modifying antirheumatic drug.