Novel iron-containing phosphate binders and anemia treatment in CKD: oral iron intake revisited

Recent reports have shown that novel phosphate binders containing iron are not only efficacious for the treatment of hyperphosphatemia but also may reduce the need for erythropoiesis-stimulating agents and intravenous (IV) iron for anemia management in patients on maintenance hemodialysis (MHD). Possible healthcare cost savings, which have not been demonstrated in a long-term study, may be an additional advantage of using such multi-pronged treatment strategies for the control of both hyperphosphatemia and iron needs. It is currently assumed that oral iron supplementation is less efficient than the IV route in patients with chronic kidney disease (CKD). The unexpected efficacy of novel iron-containing phosphate binders, such as ferric citrate, in repleting insufficient iron stores and improving the anemia of CKD could change this view. Previous assumptions of self-controlled iron uptake by 'mucosal block' or hepcidin, or else by impaired intestinal iron absorption due to CKD-associated inflammation cannot be reconciled with recent observations of the effects of ferric citrate administration. Citrate in the intestinal lumen may partly contribute to the acceleration of iron absorption. Animal experiments and clinical studies have also shown that oral iron overload can cause excessive iron accumulation despite high hepcidin levels, which are not able to block iron absorption completely. However, like with IV iron agents, no long-term safety data exist with respect to the effects of iron-containing phosphate binders on 'hard' patient outcomes. Future randomized prospective studies in patients with CKD are necessary to establish the safety of oral iron-containing phosphate binders for the control of both hyperphosphatemia and renal anemia.