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

Lancet. 1999 Jan 23;353(9149):259-66. doi: 10.1016/s0140-6736(98)09403-3.


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.

Publication types

  • Clinical Trial
  • Clinical Trial, Phase III
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Analysis of Variance
  • Antirheumatic Agents / therapeutic use*
  • Arthritis, Rheumatoid / diagnostic imaging
  • Arthritis, Rheumatoid / drug therapy*
  • Disease Progression
  • Double-Blind Method
  • Female
  • Humans
  • Immunosuppressive Agents / adverse effects
  • Immunosuppressive Agents / therapeutic use*
  • Isoxazoles / adverse effects
  • Isoxazoles / therapeutic use*
  • Leflunomide
  • Male
  • Middle Aged
  • Placebos
  • Radiography
  • Statistics, Nonparametric
  • Sulfasalazine / therapeutic use*
  • Treatment Outcome


  • Antirheumatic Agents
  • Immunosuppressive Agents
  • Isoxazoles
  • Placebos
  • Sulfasalazine
  • Leflunomide