The optimal timing of intravenous iron therapy, in relationship to the type of erythropoiesis stimulating agent (ESA) used and the timing of ESA administration, has not been systematically studied. Since long-acting ESAs became available, it has not been established if there is an optimal window for intravenous iron use following ESA administration.
This randomised, controlled, parallel-group trial compared the efficacy of intravenous iron administration (40 mg dose of iron saccharate) during either Week 1 or Week 3, following administration of a third-generation ESA (continuous erythropoietin receptor activator [CERA]). A total of 110 patients were randomised to the two treatment arms, with 57 receiving intravenous iron doses at Week 1, and 53 at Week 3 (three doses of intravenous iron per week).
The reticulocyte–haemoglobin content significantly increased after 7 and 14 days in Week 1 versus Week 3 (2.10 ± 2.30 pg vs –0.93 ± 2.84 pg, p<0001; and –0.67 ± 2.06 pg vs −1.58 ± 2.22 pg, p=0.037, respectively). However, haemoglobin values, reticulocyte counts, and transferrin saturation showed no difference between the two groups at any point during the study.
Contrary to the conclusions of the authors, the study may indicate that these two intravenous iron administration schedules are essentially undistinguishable regarding the primary therapeutic objective – to control haemoglobin concentration. Small differences in iron incorporation and haemoglobin synthesis did not translate into measurable differences in haemoglobin values.
This result may have been due to the normal baseline iron parameters of the patient group. Baseline patient characteristics showed little evidence of functional iron deficiency and patients were not treated with high doses of CERA. It is likely that in the presence of iron deficiency, or with greater doses of ESA, timing of intravenous iron administration may substantially affect therapeutic response.
The full article is available online ahead of print in Therapeutic Apheresis and Dialysis. For information on iron replacement therapy, please click here.