Efficacy and safety of leflunomide compared with placebo and sulphasalazine in active rheumatoid arthritis: a double-blind, randomised, multicentre trial. European Leflunomide Study Group

BACKGROUND: Phase II trials of leflunomide, an inhibitor of de-novo pyrimidine synthesis, have shown efficacy in rheumatoid arthritis. This double-blind randomised trial compared leflunomide with placebo and sulphasalazine in active rheumatoid arthritis. METHODS: 358 patients were randomly assigned leflunomide (100 mg daily on days 1-3, then 20 mg daily), placebo, or sulphasalazine (0.5 g daily, titrated progressively to 2.0 g daily at week 4). The primary endpoints were tender and swollen joint counts and investigator's and patient's overall assessments. Analyses were by intention to treat. FINDINGS: The mean changes in the leflunomide, placebo, and sulphasalazine groups were -9.7, -4.3, and -8.1 for tender joint count; -7.2, -3.4, and -6.2 for swollen joint count; -1.1, -0.3, and -1.0 for physician's overall assessment; and -1.1, -0.4, and -1.1 for patient's overall assessment. Leflunomide and sulphasalazine were significantly superior to placebo (p=0.0001 for joint counts; p<0.001 for assessments). Radiographic disease progression was significantly slower with leflunomide and sulphasalazine than with placebo (p<0.01). Most common adverse events with leflunomide were diarrhoea (17%), nausea (10%), alopecia (8%), and rash (10%). Transiently abnormal liver function was seen in three leflunomide-group patients and five sulphasalazine-group patients. There were two cases of reversible agranulocytosis in the sulphasalazine group. INTERPRETATION: Leflunomide was more effective than placebo in treatment of rheumatoid arthritis and showed similar efficacy to sulphasalazine. Leflunomide was well tolerated. This drug may be a useful option as a disease-modifying antirheumatic drug.