Safety and Efficacy Evaluation for the Addition of Either Etanercept or Leflunomide in Korean Rheumatoid Arthritis Patients Inadequately Responding to Methotrexate

Objective. To compare the safety and efficacy associated with the addition of etanercept (ETN) with that of leflunomide (LEF) in Korean rheumatoid arthritis (RA) patients, who inadequately respond to methotrexate (MTX) in a randomized, open-label study. Methods. Twenty-nine subjects suffering moderate to severe RA, despite MTX treatment were randomly assigned to a combination therapy with either ETN or LEF. The primary end-point was the proportion of subjects achieving American College of Rheumatology (ACR20) criteria at week 16. Results. Ninety percent (n=18) of the ETN+MTX group (n=20) and 22.2% (n=2) of the LEF+MTX group (n=9) achieved an ACR20 response (p=0.001). All patients (n=20) in the ETN+MTX group showed moderate or good EULAR response as compared with 55.6% (n=5) in the LEF+MTX group (p=0.012). All of the ETN+MTX subjects completed the study without adverse events. Adverse events occurred in 77.8% (n=7) of cases in the LEF+MTX group; significantly elevated serum AST/ALT levels in 6 subjects and mild neutropenia (ANC ＜ 1,500/μL) in 1 subject. Conclusion. The ETN+MTX combination therapy was effective and safe, whereas the LEF+MTX combination therapy resulted in moderate efficacy in only half of the cases, and was accompanied by a high rate of adverse events. Elevated AST/ALT was the most common adverse event causing dose adjustment or discontinuation of therapeutic agent in the LEF+MTX group. KCI Citation Count: 1