Availability of iron and degree of inflammation modifies the response to recombinant human erythropoietin when treating anemia of chronic disease in patients with rheumatoid arthritis
Forty-six patients with rheumatoid arthritis (RA) and documented anemia of chronic disease (Hb <100/110 g/l) were randomized to receive either human recombinant erythropoietin (r-HuEPO, n = 36, 300 U/kg body weight) or placebo (n = 10) for 12 weeks in a multicenter study. An adequate response was defined as elevation of Hb≥120 g/l. Relevant clinical and laboratory assessments were made to evaluate efficacy and secure safety. A significant elevation in Hb from week 10 onwards was noted in twenty-six patients (five drop-outs) out of nine patients receiving placebo (one drop-out) (12±1.2 g/l vs 4±0.5 g/l; Hb elevation from 95 g/l to 107 g/l vs 93 g/l to 97 g/l, P<0.05). Only 14.6%, however, were considered responders according to preset criteria. In the responders a lower initial CRP, a significant reduction in ESR but not in CRP was seen compared to the remaining r-HuEPO group. A significant elevation of energy level was noted in the r-HuEPO group; otherwise, no differences in clinical variables were seen. No serious adverse effects were noted. When analyzing patients receiving oral iron in combination with r-HuEPO and adding five additional, openly selected patients receiving both adequate iron supplementation and r-HuEPO, there was a significant weekly elevation of Hb from week 8 onwards in favor of combination therapy over the ones only receiving r-HuEPO (18±1.1 g/l vs 7±1.1 g/l, P<0.05). The initial six responders had now reached ten of whom seven belonged to the combination therapy group. Response to r-HuEPO in RA patients appears to be dependent on availability of iron and on the degree of inflammation. If r-HuEPO treatment is considered, iron deficiency should always be corrected and strenous efforts should have been made to control the disease itself.