To evaluate the effect of antitumor necrosis factor-alpha monoclonal antibody infliximab treatment on anemia in patients with rheumatoid arthritis (RA).
Data from patients with RA who received infliximab or placebo in the multicenter, placebo-controlled, double-blind, randomized ATTRACT, ASPIRE, and START studies were included in this post-hoc, pooled analysis. Infliximab (3 to 10 mg/kg) was administered every 4 or 8 weeks, and all patients received stable doses of methotrexate (MTX). We determined the percentage of anemic patients (baseline hemoglobin level <12 g/dL) who had an increase from baseline in hemoglobin level greater than or equal to 1 or 2 g/dL or achieved normal hemoglobin level at week 22. The association of improvement in anemia with improvement in clinical parameters was also evaluated.
Among patients with anemia at baseline, infliximab plus MTX treatment produced a significantly greater mean (standard deviation) increase in hemoglobin level from baseline to week 22 (0.74 [1.12], P < 0.0001) than placebo plus MTX (0.30 [0.92]). Significantly (P < 0.001) greater proportions of anemic patients treated with infliximab plus MTX had either at least a 1 g/dL (40%) or at least a 2 g/dL (12%) increase in hemoglobin level from baseline to week 22 or achieved normal hemoglobin level (43%) when compared with placebo plus MTX (19, 5, and 28%, respectively). Greater improvement in hemoglobin level among infliximab plus MTX-treated patients was consistently observed across subgroups and in patients without clinical response (American College of Rheumatology 20% response criteria) at week 22. Multiple regression analysis indicated that the effect of infliximab plus MTX on anemia was independent of improvement in disease activity.
Treatment with infliximab plus MTX significantly improved hemoglobin level among anemic RA patients when compared with treatment with placebo plus MTX, even after adjusting for improvement in disease activity.