Azathioprine and methotrexate as combination chemotherapy in rheumatoid arthritis.

Azathioprine or methotrexate (MTX) are each established, and comparably effective, therapies for rheumatoid arthritis (RA). An ongoing, still double blind, 3-arm, 24-week study comparing azathioprine or MTX, or azathioprine and MTX in RA is described. With 146 (of 210 total) patients enrolled, it is apparent that all 3 treatment groups demonstrate clinically significant improvement at Week 24. One treatment arm (Group 1) showed a greater degree of improvement in raw mean scores for most outcome variables. Another treatment arm (Group 2) had an adverse effect dropout rate exceeding the sum of adverse effect dropouts from Group 1 and Group 2. Most adverse effects were due to gastrointestinal intolerance.