To determine whether treatment with leflunomide (LEF), methotrexate (MTX), or sulfasalazine (SSZ) for 6-12 months retards progression of radiographic damage and to identify clinical variables that correlate with radiographic progression.
Radiographs of the hands and feet were performed at baseline and at the end of study or early exit in 3 randomized controlled trials. Protocol US301 was a 12-month controlled trial of LEF or MTX treatment compared with placebo in 482 patients randomized in a 3:3:2 ratio. Protocol MN301 compared 6 months of LEF or SSZ treatment with placebo in 358 patients, randomized in a 3:3:2 ratio, with continued blinded treatment in the active control arms for 12 months. Protocol MN302 compared 12 months of LEF treatment with MTX in 999 patients. Radiographs were blinded for sequence and treatment and were scored for erosions and joint space narrowing. All analyses were by intent-to-treat. Sensitivity analyses were performed to account for missing data.
LEF, MTX, and SSZ treatment resulted in statistically significantly less radiographic progression compared with placebo at 6 and 12 months: for protocol US301, LEF versus placebo P = 0.0007 and MTX versus placebo P = 0.0196; for protocol MN301, LEF versus placebo P = 0.0004 and SSZ versus placebo P = 0.0484. The effect of LEF treatment was similar to that of MTX and SSZ.
These are the first 6- and 12-month randomized placebo- and active drug-controlled trials to demonstrate retardation of radiographic progression by a new disease-modifying antirheumatic drug (DMARD), LEF, as well as 2 commonly used DMARDs, MTX and SSZ.