1. CU-1 Iron Overload: Complications and Need for Therapy John B. Porter, MD Professor of Hematology University College, London, UK

2. CU-2 Iron Distribution & Turnover In Humans Erythron 2g Macrophages 0.6g Transferrin 3mg 20-30 mg/day 2-3mg/day 1-2 mg day Gut 20-30mg/day Adapted with permission from Porter JB; Hematol/Oncol Clinics 2005; 19, 1-6. Andrews NC. N Engl J Med. 1999; 341:1986-1995. Parenchyma 0.3g Liver 1g

3. CU-3 Iron Loading From Blood Transfusions  1 unit of blood contains approximately 200 mg of iron a –Normally, total body iron is approximately 3 to 4 g –Chronic transfusion-dependent patients have an iron excess of 0.3 to 0.7 mg/kg/day, equivalent to 4 to 10 g of iron per year b  Iron accumulates with repeated blood transfusion a Porter JB. Br J Haematol. 2001;115:239-252. b Andrews NC. N Engl J Med. 1999;341:1986-1995.

4. CU-4 Parenchyma Hepatocytes Hepatocytes Parenchyma Transfusional Iron Overload Red Erythron Macrophages Gut Transfusion 20-40mg/day (0.3- 0.7 mg/kg/d) NTBI Transferrin Adapted with permission from Porter JB; Hematol/Oncol Clinics 2005 19,1-6

5. CU-5 Organ Systems Affected by Iron Overload Pituitary gland Heart Liver Pancreas Gonadal Iron overload results in non–transferrin-bound iron in the plasma Increased iron uptake into selective organs Generation of free hydroxyl radicals Tissue damage

6. CU-6 Complications of Iron Overload  Cardiomyopathy and cardiac failure  Hepatic cirrhosis  Diabetes mellitus  Impaired growth  Hypogonadism and infertility Andrews NC. N Engl J Med. 1999;341:1986–1995

7. CU-7 Diseases Associated With Transfusional Iron Overload  β-thalassemia  Other chronic anemias –Fanconi anemia (hypoplastic anemia) –Diamond-Blackfan anemia (red cell aplasia) –Congenital dyserythropoietic anemias  Sickle cell anemia  Aplastic anemia  Myelodysplastic syndromes (MDS) Andrews NC. N Engl J Med. 1999;341:1986-1995.

8. CU-8 Initiation of Therapy for Iron Overload Current Practice  With repeated blood transfusions, iron rapidly accumulates in the body –Chelation treatment is generally initiated after 10 to 20 transfusions or when serum ferritin > 1000 µg/L –Alternatively, if iron loading is unclear, LIC may be measured LIC = Liver iron concentration. Porter JB. Br J Haematol. 2001;115:239-252.

9. CU-9 Liver Iron Concentration Accurately Reflects Total Body Iron Stores Reprinted with permission from Angelucci E, et al. N Engl J Med. 2000;343:327-331. Liver iron concentration (LIC), mg/g dry weight Total body iron stores, mg/kg 0510152025 300 250 200 150 100 50 0 r = 0.98 Stores calculated by quantitative phlebotomy LIC measured from biopsy samples ≥ 1 mg dry weight in 25 patients Body iron (mg/kg) = 10.6 x LIC (mg/g dry wt)

10. CU-10 HH heterozygotes 50403020100 50 100 150 200 250 Age, years Hepatic iron, µmol/g wet weight 50 40 30 20 10 0 Hepatic iron, mg/g dry weight Threshold for cardiac disease and early death Increased risk of complications Normal Olivieri & Brittenham, 1997 Blood. 89; 739-761. Thalassemia major Liver Iron and Risk of Complications From Iron Overload 0

11. CU-11 Plasma Ferritin as a Monitor of Iron Loading  Relatively non-invasive  Inexpensive  Obtained as routine laboratory assay  Values confounded by –Inflammation –Liver function 040008000 12000 24,000 12,000 8000 4000 0 Hepatic iron, µg Fe/g liver * Plasma ferritin, µg/L Brittenham et al. Am J Hematol. 1993;42:81. Sickle cell anemia (n = 37) Thalassemia major (n = 74)

12. CU-12 Liver Iron Concentration and Serum Ferritin  Change in serum ferritin over time reflects change in LIC –Sequential evaluation of ferritin levels provides a good index of chelation history a  Maintenance of serum ferritin < 2500 µg/L significantly correlates with cardiac disease-free survival b,c,d,e a Gabutti V and Piga A. Acta Haematol. 1996;95:26-36. b Olivieri NF, et al. N Engl J Med. 1994;331:574-578. c Telfer PT, et al. Br J Haematol. 2000;110:971-977. d Davis BA, et al. Blood. 2004;104:263-269. e Borgna-Pignatti C, et al. Haematologica. 2004;89:1187-1193.

13. CU-13 Cardiac Disease and % of Time With Serum Ferritin > 2500 µg/L Olivieri, et al. N Engl J Med. 1994;331:574. Assessments > 2500 µg/L 1.00 0.75 0.50 0.25 0 0246810121416 Years of chelation therapy Proportion without cardiac disease < 33% 33% - 67% > 67%

14. CU-14 Ideal Properties of an Iron Chelator  Control of body iron  Prevention of iron mediated organ toxicity  Simplicity and ease of administration  Once daily oral administration  Suitable for monotherapy  Acceptable toxicity profile –Iron free drug - dose relationship –Iron complex - stable no redistribution of iron  Simplicity and ease of monitoring

15. CU-15 Current Therapy for Iron Overload  Deferoxamine (Desferal ® ) is the only drug available in US to treat iron overload  Because of short half-life (20 minutes), must be given by continuous infusion –8 to 12 hours/day, 5 to 7 days/week  Compliance is poor because of side effects and quality-of-life issues  Oral therapy is highly desirable Porter JB and Huehns CR. Baillieres Clin Haematol. 1989;2:459-474.

16. CU-16 Compliance With Deferoxamine Infusions Is Related to Survival in Thalassemia Kaplan-Meier analysis of survival in 257 consecutive thalassemic patients according to the mean compliance with subcutaneous DFO therapy Age, years Survival, % 0 10 20 30 40 50 60 70 80 90 100 0246810121416182022242628303234363840 0 - 75 75 - 150 150 - 225 225 - 300 300 - 365 Gabutti V and Piga A. Acta Haematol. 1995;95:26-36. Deferoxamine infusions/year

17. CU-17 Summary of Medical Need  Transfusional therapy results in iron overload  Currently, the only approved therapy for iron overload in US is deferoxamine, which requires subcutaneous infusion for 8 to 12 hours, 5 to 7 times per week –Compliance is an issue –Many patients are not adequately treated Treadwell MJ, et al. Pediatr Blood Cancer. 2005;44:500-507. Porter JB and Huehns CR. Baillieres Clin Haematol. 1989;2:459-474.

18. CU-18 Summary of Medical Need  Inadequately treated iron overload leads to organ toxicity –Related to lack of control of reactive iron, and deposition of iron in key tissues –Developmental and endocrine dysfunction –Cardiac dysfunction results in early death Beutler E, et al. Hematology (Am Soc Hematol Educ Program). 2004:40-61.