Objectives and mechanism of iron chelation therapy.
Prevention of cardiac mortality is the most important beneficial effect of iron chelation therapy. Unfortunately, compliance with the rigorous requirements of daily subcutaneous deferoxamine (DFO) infusions is still a serious limiting factor in treatment success. The development of orally effective iron chelators such as deferiprone and ICL670 is intended to improve compliance. Although total iron excretion with deferiprone is somewhat less than with DFO, deferiprone may have a better cardioprotective effect than DFO due to deferiprone's ability to penetrate cell membranes. Recent clinical studies indicate that oral ICL670 treatment is well tolerated and is as effective as parenteral DFO used at the standard dose of 40 mg/kg of body weight/day. Thus, for the patient with transfusional iron overload in whom results of DFO treatment are unsatisfactory, several orally effective agents are now available to avoid serious organ damage. Finally, combined chelation treatment is emerging as a reasonable alternative to chelator monotherapy. Combining a weak chelator that has a better ability to penetrate cells with a stronger chelator that penetrates cells poorly but has a more efficient urinary excretion may result in improved therapeutic effect through iron shuttling between the two compounds. The efficacy of combined chelation treatment is additive and offers an increased likelihood of success in patients previously failing DFO or deferiprone monotherapy.
Hershko
Chaim
C
Department of Hematology, Shaare Zedek Medical Center, P.O. Box 3235, Jerusalem, Israel. hershko@szmc.org.il
Link
Gabriela
G
Konijn
Abraham M
AM
Cabantchik
Z Ioav
ZI
D000818:Animals; D001565:Benzoates / Q000494:pharmacology / Q000627:therapeutic use; D009202:Cardiomyopathies / Q000209:etiology / Q000517:prevention & control*; D002478:Cells, Cultured; D015913:Chelation Therapy; D002986:Clinical Trials as Topic; D000077588:Deferasirox; D000077543:Deferiprone; D003676:Deferoxamine / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D004333:Drug Administration Routes; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D005293:Ferritins / Q000502:physiology; D006801:Humans; D007501:Iron / Q000378:metabolism; D007502:Iron Chelating Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D019190:Iron Overload / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control*; D008929:Mitochondria, Heart / Q000187:drug effects / Q000201:enzymology; D012157:Mononuclear Phagocyte System / Q000502:physiology; D011728:Pyridones / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D013789:Thalassemia / Q000150:complications / Q000188:drug therapy* / Q000628:therapy; D065227:Transfusion Reaction; D014230:Triazoles / Q000494:pharmacology / Q000627:therapeutic use
D001565:Benzoates; D007502:Iron Chelating Agents; D011728:Pyridones; D014230:Triazoles; D000077543:Deferiprone; D005293:Ferritins; D007501:Iron; D003676:Deferoxamine; D000077588:Deferasirox