Sept Iron Overload and Treatment with a New Iron Chelator Morey Blinder 5/21/04

2 Andrews NC. N Engl J Med. 1999;341: Body Iron Distribution and Storage Dietary iron Utilization Duodenum (average, mg per day) Muscle (myoglobin) (300 mg) Liver (1,000 mg) Bone marrow (300 mg) Circulating erythrocytes (hemoglobin) (1,800 mg) Reticuloendothelial macrophages (600 mg) Sloughed mucosal cells Desquamation/Menstruation Other blood loss (average, mg per day) Storage iron Plasma transferrin (3 mg) Iron loss

3 Major Iron Compartments Metabolic –Hemoglobin mg –Myoglobin mg Storage –Iron storage mg Transit –Serum iron3 mg Total mg

4 Basic Causes of Iron Overload Hereditary –HFE hemochromatosis Homozygous C282Y mutation in HFE gene 1 Defective regulatory receptor in intestine –Other genetic mutations Acquired (secondary) iron overload 2 –Transfusional –Ineffective erythropoiesis –Toxic ingestion (rare) 1. Feder JN, et al. Nat Genet. 1996;13: Porter JB. Br J Haematol. 2001;115:

5 Iron Loading From Blood Transfusions 1 unit of blood contains approximately 200 to 250 mg of iron –Chronic transfusion-dependent patients have an iron excess of ~ 0.4 to 0.5 mg/kg/day (1g/month) With repeated infusions, iron accumulates –Signs of iron overload can be seen anywhere between 10 and 20 transfusions Unlike with hereditary hemochromatosis, phlebotomy to remove excess iron is usually not an option for patients with chronic anemias 1. Porter JB. Br J Haematol. 2001;115: Kushner JP, et al. Hematology. 2001;47-61.

6 Diseases Associated With Transfusional Iron Overload  -thalassemia (major and intermedia) Sickle cell anemia Aplastic anemia Myelodysplastic syndromes Rare chronic anemias –Fanconi’s anemia (hypoplastic anemia) –Blackfan-Diamond anemia (red cell aplasia) –Congenital dyserythropoietic anemias

7 Possible Complications of Iron Overload Cardiac failure Liver cirrhosis/fibrosis/cancer Diabetes mellitus Infertility Arthritis Andrews NC. N Engl J Med. 1999;341:

8 Monitoring Iron Overload Serum ferritin concentration –Noninvasive –Accuracy in iron overload questionable 1 Liver iron content (LIC) 1 –Liver biopsy Reference standard –SQUID Noninvasive, availability limited –MRI Noninvasive, investigational technique 2 SQUID = Superconducting Quantum Interference Device Brittenham GM, et al. Blood. 2003;101: Cook JD, et al. Blood. 2003;101:

9 Advantages of Liver Biopsy Historically, the reference method for measuring LIC Quantitative, specific, and sensitive Allows for measurement of non-heme storage iron Provides insight into liver histology/pathology Olivieri NF, et al. Blood. 1997;89:

10 Monitoring LIC by SQUID Superconducting QUantum Interference Device –High-power magnetic field –Iron interferes with the field –Changes in the field are detected Noninvasive, sensitive, and accurate Limited availability –Superconductor requires high maintenance –Only 4 machines worldwide Photograph courtesy of A. Piga

11 Monitoring Iron Overload by MRI Clark PR, et al. Magn Reson Med. 2003;49: Image courtesy of T. St. Pierre An R2 image of an iron-overloaded human liver superimposed on a T-2 weighted image. Bright areas represent high iron concentration; dark areas represent low iron concentration.

12 T ½, AgentRoutehours Schedule ClearanceToxicity DeferoxamineSlow hoursRenalInfusion site rxns, (Novartis) infusion days andallergic rxns, per week hepaticocular, auditory DeferiproneOral dailyRenalNausea/vomiting, (Apotex)arthropathy, neutropenia, agranulocytosis,  liver fibrosis (?) ICL670Oral dailyHepato-Transient nausea, (Novartis) biliary diarrhea, rash Iron Chelation Agents Approved or in Development

13 Deferoxamine: the Only Treatment for Transfusional Iron Overload Available in the US Deferoxamine –Indicated for first-line treatment of iron overload –Reduces comorbidities, including fatal iron overload –The “gold-standard” therapy Challenges of therapy –Subcutaneous slow infusion 5 to 7 nights/week –Infusion-site reactions and pain –High degree of noncompliance –Approximate cost $ /month

14 Deferiprone Side effects –Nausea, vomiting, abdominal pain –Arthralgia –Neutropenia/Agranulocytosis Weekly neutrophil count recommended Efficacy –For second-line use in deferoxamine-intolerant patients with  -thalassemia major –May be less effective than deferoxamine in reducing LIC 1 –Reports of increased risk of liver fibrosis Ferriprox ® [package insert]. Apotex Europe Ltd Hoffbrand AV, et al. Blood. 2003;102:17-23.

15 ICL670: a New, Oral Iron Chelator Selected from more than 700 compounds tested Tridentate* iron chelator –An oral, dispersible tablet –Administered once daily –Highly specific for iron Chelated iron excreted mainly in feces (< 10% in urine) O OH HO OH NN N Fe * * * *3 polar interaction sites in the binding pocket. Nick H, Current Medicinal Chemistry. 2003;10: Clinical trial formulation or preparation

16 Phase I Pharmacokinetic and Pharmacodynamic Study: Multiple Doses in Thalassemia Patients Randomized, double-blind, placebo-controlled sequential trial to assess –Short-term safety (12-day exposure) –Efficacy (iron balance) –Pharmacokinetic/pharmacodynamic relationships 3 cohorts of 7 patients with  -thalassemia –5 patients per cohort received active drug, 2 received placebo –Doses: 10, 20, 40 mg/kg Nisbet-Brown E, et al. Lancet. 2003;361:

17 ICL mg/kg20 mg/kg 40 mg/kg Preferred term Severity(n = 5)(n = 6)(n = 7) NauseaMild– 21 NauseaModerate– – 1 DiarrheaMild– 13 Abdominal pain Mild– – 1 ICL670 Phase I Safety Profile Treatment-Related Adverse Events by Dose Level Nisbet-Brown E, et al. Reprinted with permission from Elsevier (Lancet, 2003;361: ).

18 Phase II Trial of ICL670 in Thalassemia: Objectives Primary –Safety and tolerability profile Secondary –Effects on LIC by SQUID –Pharmacokinetics Determine dose titration

19 Phase II Patient Selection Criteria Inclusion –Transfusion-dependent  -thalassemia –Age  18 years –Serum ferritin, 2,000 to 8,000 ng/mL –LIC, 5 to 15 mg/g dry weight Exclusion –Alanine aminotransferase: > 250 Units/L –Creatinine clearance: < 80 mL/min –Significant EKG irregularities Cappellini M, et al. 16th Annual Meeting of the International BioIron Society

20 ICL670 Phase II Safety Profile Mild transient gastrointestinal adverse events in some patients including dose-related nausea/vomiting –Resolved spontaneously No myelosuppression No clinically relevant toxicities in kidney, eye, ear, heart, or liver Occasional elevations in urinary  2 m and mild proteinuria of uncertain clinical significance Cappellini M, et al. 16th Annual Meeting of the International BioIron Society

21 Summary of Phase II Results Results after 12 months of therapy with ICL670 in patients with  -thalassemia and transfusional iron overload: –No serious adverse events –No clinically significant safety issues –Dose-dependent pharmacokinetics –ICL670 (20 mg/kg/day) demonstrated comparable efficacy to deferoxamine (40 mg/kg/day) in decreasing LIC over a 1-year treatment period

22 Study 0109: Phase II Comparative Trial Adult and Pediatric Sickle Cell Disease Primary analysis –Safety and tolerability profile of ICL670 relative to that of deferoxamine in adult and pediatric patients with sickle cell disease Study design –1-year trial 170 patients on transfusion programs Randomized ~2:1 to ICL670 or deferoxamine –SQUID assessment of LIC Doses adjusted according to SQUID results –Substudy of LIC assessed by MRI and liver biopsy (n = 30)

23 Patient Population (Eligiblity) Common variant of sickle cell disease (Hgb SS, Sbeta°, Sbeta +, SC) Evidence of iron overload from transfusion therapy –Chronic simple transfusions –Exchange transfusions –Intermittent simple transfusions with ≥20 units PRBCs Adequate renal, hepatic and cardiac function No pregnant patients No patient requiring hydroxyurea Age ≥ 2 years Serum ferritin ≥ 1000 µg/L Able to sign consent

24 Endpoints Total duration of study will be 1 year Absolute and relative change of liver iron concentraiton after 1 year of treatment will be analyzed as primary efficacy end point All adverse events will be monitored and recorded

25 Conclusions ICL670 has shown promise in phase II clinical trials in patients with transfusional iron overload –Efficacy after 1 year comparable to that of deferoxamine, the current reference standard –Once-daily oral chelation may lead to improved compliance in the treatment of iron overload ICL670 is currently being studied in 12 countries and in more than 800 patients –Adults and children with  -thalassemia, MDS, sickle cell disease, and other anemias Will this lead to chelation euphoria?