Advancements in the Understanding of atypical Haemolytic Uraemic Syndrome (aHUS)

Program Objectives Highlight that atypical haemolytic uraemic Syndrome (aHUS) is a genetic, life-threatening, and chronic disease Explain the role of complement in aHUS Demonstrate how complement-amplifying conditions place patients with aHUS at high risk for TMA manifestations How to approach a differential diagnoses of aHUS Explore limitations of historical supportive care options

aHUS: Complement-Mediated Thrombotic Microangiopathy (TMA)1-4 Due to a genetic deficiency of complement regulators, aHUS is a permanent, ongoing disease of systemic, complement-mediated TMA1,2 Defined by the clinical characteristics of TMA: Decreased platelet count1 Evidence of microangiopathic haemolysis3 Evidence of organ impairment/damage (e.g., serum creatinine >ULN)2,3 Complement-amplifying conditions may unmask aHUS4 Affects both adults and children2 References: 1. Noris M et al. N Engl J Med. 2009;361:1676-1687. 2. Noris M et al. Clin J Am Soc Nephrol. 2010;5:1844-1859. 3. Desch K et al. JASN. 2007;18:2457-2460. 4. Kavanagh D et al. British Medical Bulletin. 2006; 77 and 78: 5-22.

Distinct Pathophysiologies Differentiate aHUS and TTP Genetic, complement-mediated TMA (aHUS) Underlying cause: chronic, uncontrolled complement activity1-5 Genetic defects in activators and/or inhibitors lead to chronic activity of the complement system, causing endothelial cell damage and continuous platelet aggregation1-5 Treatment goal: Address underlying chronic complement activity Severe ADAMTS13 deficiency (TTP) Underlying cause: severe deficiency in ADAMTS13 activity (≤5%) 6-10 Insufficient ADAMTS13 activity (≤5%) leaves von Willebrand factor uncleaved, causing excessive platelet aggregation8,7,11,12 Treatment goal: Removal of autoantibodies against ADAMTS13 Normal ADAMTS13 activity ADAMTS13 deficiency vWF cleaved vWF uncleaved References: 1. Noris M, Caprioli J, Bresin E, et al. Clin J Am Soc Nephrol. 2010;5:1844-1859. 2. Noris M, Remuzzi G. N Engl J Med. 2009;361:1676-1687. 3. Holers VM. Immunol Rev. 2008;223:300-316. 4. Loirat C, Frémeaux-Bacchi V. Orphanet J Rare Dis. 2011;6:60. 5. Fang CJ, Richards A, Liszewski MK, et al. Br J Haematol. 2008;143: 336-348. 6. Hirt-Minkowski P, Dickenmann M, Schifferli JA. Nephron Clin Pract. 2010;114:c219-c235. 7. Tsai H-M. Int J Hematol. 2010;91:1-19. 8. Sadler JE. Blood. 2008; 112:11-18. 9. Bianchi V, Robles R, Alberio L, et al. Blood. 2002;100:710-713. 10. Barbot J, Costa E, Guerra M, et al. Br J Haematol. 2001;113:649-651. 11. Moake JL. N Engl J Med. 2002;347:589-600. 12. Tsai H-M. Am J Med. 2013;126:200-209.

aHUS: A Chronic, Complement-Mediated TMA with Life-Threatening Consequences1,2 Patients diagnosed with aHUS are at immediate and ongoing risk of progressive clinical deterioration despite intensive use of Plasma Exchange/Plasma Infusion (PE/PI)1,2 aHUS may result in death and progressive damage 79% of aHUS patients die, require dialysis or have permanent renal damage within 3 years1 33 to 40% of patients die or progress to end-stage renal disease with the first clinical manifestation despite PE/PI1,2 1.00 Up to 70% of patients (with the most common mutation, CFH) die, require dialysis, or have permanent renal damage within 1 year2 0.75 Cumulative Fraction of Patients Free of Events 0.50 0.25 94% of patients received PE/PI for the first TMA manifestation2 0.00 3 6 12.5 Follow Up (months) Modified from Caprioli J et al. Blood. 2006. CFH mutation depicted. References: 1. Noris M, Caprioli J, Bresin E, et al. Clin J Am Soc Nephrol. 2010;5:1844-1859. 2. Caprioli J, Noris M, Brioschi S, et al; for the International Registry of Recurrent and Familial HUS/TTP. Blood. 2006;108:1267-1279.

PE/PI Does Not Reduce Morbidity in aHUS1 Despite PE/PI, the renal outcome for patients with aHUS has remained poor2 Renal outcome one year after aHUS diagnosis was comparable between patients with PE/PI and without PE/PI1 P=0.98 34% 33% Received PE/PI* No PE/PI % of patients Patients requiring dialysis at 1 year1 Study description: Analysis of patients from the aHUS registry of the GPN (working Group for Pediatric Nephrology). 141 patients were included in the registry at the time of this analysis. Data on treatment of initial manifestations was available for 99 patients. Footnote: *Forty-two (38/89) percent of patients received PE. 48% (45/93) received PI, and 22 patients received both PE and PI. References: 1. Riedl M, Hofer J, A Rosales, et al. Initial plasma therapy in patients with atypical HUS: No negative predictive value for the outcome after one year. Klin Padiatr. 2011;223-P031. 2. Fakhouri F et al. Am J Kidney Dis. 2013;1:40-8.

No Identifiable Mutation Identifiable Mutation Regardless of Whether or not a Mutation is Identified, Patients with aHUS have Similarly Devastating Outcomes1,2 Consequences No Identifiable Mutation Identifiable Mutation % of patients that died or progressed to ESRD within the first clinical manifestation1,2 28-37% 40-44% % of patients that died, required dialysis, or had permanent renal damage within the first year after diagnosis2 65% 63% % of Death, ESRD, or permanent renal damage: Outcome at 3 years1 82% 76% Footnotes: ESRD = end state renal disease. References: 1. Noris M et al. Clin J Am Soc Nephrol. 2010;5:1844-1859. 2. Caprioli et al. Blood. 2006;108:1267-1272.

The Role of Complement in aHUS

Natural Complement Regulators are Required for Control of the Complement System1-3 The complement system is part of the natural (innate) protective immune system1 Activity is continuously occurring by a spontaneous process called “tick-over” which enables rapid immune responses1 Natural inhibitors of complement keep amplification in check and prevent uncontrolled complement activity2 When unregulated, complement activity can lead to destructive consequences, including TMA lesions and progressive organ damage3 References: 1. Holers VM et al. Immunol Rev. 2008;223:300-316. 2. Zipfel PF et al. Curr Opin Nephrol Hypertens. 2010;4:372-378. 3. Legendre CM, Licht C, Muus P, et al. N Engl J Med. 2013;368:2169-2181

Immune Complex Clearance Microbial Opsonisation Natural Inhibitors are Required for Control of the Complement System1-17 Lectin Pathway Classical Pathway Alternative Pathway iC3b C3-Convertase C3b Immune Complex Clearance Microbial Opsonisation Weak Anaphylatoxin C3a C3 + H2O: always active (chronic) C3 Amplification Natural Inhibitors: Factor I, Factor H, MCP Proximal Thrombomodulin C5b-9 (Membrane Attack Complex) Cell lysis Proinflammatory Platelet activation Leukocyte activation Endothelial activation Prothrombotic C5a Potent anaphylatoxin Chemotaxis C5 C5-Convertase Terminal C5b C6 C7 C8 C9 References: 1. Zipfel PF et al. Vaccine 2008;26(Suppl 8):I67-I74. 2.Figueroa JE, Densen P. Clin Microbiol Rev. 1991;4:359-395. 3. Walport MJ. N Engl J Med. 2001;344:1058-1066. 4. Rother RP et al. Nat Biotechnol. 2007;25:1256-1264. 5. Meyers G et al. Blood. 2007;110:abs 3683. 6. Hill A et al. Br J Haematol. 2010;149:414-425. 7. Hillmen P et al. Am J Hematol. 2010;85:553-559. 8. Parker C et al. Blood. 2005;106:3699-3709. 9. Hillmen P et al. N Engl J Med. 1995;333:1253-1258. 10. Nishimura J et al. Medicine. (Baltimore) 2004;83:193-207. 11. Caprioli J et al. Blood. 2006;108:1267-1279. 12. Noris M et al. Clin J Am Soc Nephrol. 2010;5:1844-1859. 13. George JN. Blood. 2010;116:4060-4069. 14. Loirat C et al. Pediatr Nephrol. 2008;23:1957-1972. 15. Ståhl AL et al. Blood. 2008;111:5307-5315. 16. Hosler GA et al. Arch Pathol Lab Med. 2003;127;834-839. 17. Ariceta G et al. Pediatr Nephrol. 2009;24:687-696..

Immune Complex Clearance Microbial Opsonisation In aHUS, Chronic Uncontrolled Complement Activity Leads to Devastating Consequences1-17 Lectin Pathway Classical Pathway Alternative Pathway Immune Complex Clearance Microbial Opsonisation C3 C3 + H2O: always active (chronic) Amplification Natural Inhibitors: Factor H, Factor I, MCP − Proximal Weak Anaphylatoxin C3a C3b Thrombomodulin − iC3b C3-Convertase Gain of Function Mutations: C3, CFB + C5-Convertase C5 Terminal C5b C6 C7 C8 C9 C5a Potent anaphylatoxin Chemotaxis Proinflammatory Leukocyte activation Endothelial activation Prothrombotic C5b-9 (Membrane Attack Complex) Cell lysis Proinflammatory Platelet activation Leukocyte activation Endothelial activation Prothrombotic Consequences Consequences Anaphylaxis Inflammation Thrombosis Haemolysis Inflammation Thrombosis Tissue Damage References: 1. Zipfel PF et al. Vaccine 2008;26(Suppl 8):I67-I74. 2.Figueroa JE, Densen P. Clin Microbiol Rev. 1991;4:359-395. 3. Walport MJ. N Engl J Med. 2001;344:1058-1066. 4. Rother RP et al. Nat Biotechnol. 2007;25:1256-1264. 5. Meyers G et al. Blood. 2007;110:abs 3683. 6. Hill A et al. Br J Haematol. 2010;149:414-425. 7. Hillmen P et al. Am J Hematol. 2010;85:553-559. 8. Parker C et al. Blood. 2005;106:3699-3709. 9. Hillmen P et al. N Engl J Med. 1995;333:1253-1258. 10. Nishimura J et al. Medicine. (Baltimore) 2004;83:193-207. 11. Caprioli J et al. Blood. 2006;108:1267-1279. 12. Noris M et al. Clin J Am Soc Nephrol. 2010;5:1844-1859. 13. George JN. Blood. 2010;116:4060-4069. 14. Loirat C et al. Pediatr Nephrol. 2008;23:1957-1972. 15. Ståhl AL et al. Blood. 2008;111:5307-5315. 16. Hosler GA et al. Arch Pathol Lab Med. 2003;127;834-839. 17. Ariceta G et al. Pediatr Nephrol. 2009;24:687-696..

Elevated Baseline Complement Activity Chronic Complement Activity Chronic, Uncontrolled Complement Activity Results in Continuous Endothelial Damage and Ongoing Risk of TMA1 Elevated Baseline Complement Activity Chronic Complement Activity The assembly of multiple C5b-9 complexes on the surface of endothelial cells causes endothelial injury and platelet activation2-5 Binding of C5a to the C5a receptor, results in a decrease in the endothelium’s anti-complement and anti-thrombotic properties2,4,6,7 red blood cell leukocyte platelet activated leukocyte activated platelet vWF prothrombotic factors schistocyte Footnotes: vWF = Von Willebrand Factor; Image for illustrative purposes only, objects are not to scale. References: 1. Noris M and Remuzzi G Nat Rev Nephrol. 2014;10(3):174-80. 2. Noris M, Mescia F, Remuzzi G. Nat Rev Nephrol. 2012;8:622-633. 3. Barbour T, Johnson S, Cohney S, et al. Nephrol Dial Transplant. 2012;27:2673-2685. 4. Fang CJ, Richards A, Liszewski MK, et al. Br J Haematol. 2008;143:336-348. 5. Loirat C, Frémeaux-Bacchi V. Orphanet J Rare Dis. 2011;6:60. 6. Gastoldi S, Noris M, Macor P, et al. Immunobiology. 2012;217:1145-1146. 7. Salant DJ. J Am Soc Nephrol. 2011;22:7-9.

Chronic, Uncontrolled Complement Activity Results in Continuous Endothelial Damage and Ongoing Risk of TMA1 Elevated Baseline Complement Activity Chronic Complement Activity Complement-Mediated TMA Disrupted endothelial cells: Release complement- activating microparticles, resulting in a vicious cycle of endothelial activation, complement amplification, and ongoing endothelial injury2,3 Release pro-thrombotic coagulation proteins, activate platelets, and recruit leukocytes, resulting in the formation of thrombi in small blood vessels throughout the body2 red blood cell leukocyte platelet activated leukocyte activated platelet vWF prothrombotic factors schistocyte Footnotes: vWF = Von Willebrand Factor; Image for illustrative purposes only, objects are not to scale. References: 1. Noris M and Remuzzi G Nat Rev Nephrol. 2014;10(3):174-80. 2. Noris M, Mescia F, Remuzzi G. Nat Rev Nephrol. 2012;8:622-633. 3. Renner B, Klawitter J, Goldberg R, et al. J Am Soc Nephrol. 2013;24:1849-1862.

Chronic, Uncontrolled Complement Activity Results in Continuous Endothelial Damage and Ongoing Risk of TMA1 Elevated Baseline Complement Activity Chronic Complement Activity Complement-Mediated TMA Ischemia Progressive Organ Damage red blood cell leukocyte platelet activated leukocyte activated platelet vWF prothrombotic factors schistocyte Uncontrolled complement activity causes ongoing vascular endothelial injury2-5 Resulting TMA lesions may progress toward irreversible multi-organ damage2-5 Footnotes: vWF = Von Willebrand Factor; Image for illustrative purposes only, objects are not to scale. References: 1. Noris M and Remuzzi G Nat Rev Nephrol. 2014;10(3):174-80. 2. Laurence J. Clin Adv Hematol Oncol. 2012;10(suppl 17):1-12. 3. Legendre CM, Licht C, Muus P, et al. N Engl J Med. 2013;368:2169-2181. 4. Sellier-Leclerc A-L, Frémeaux-Bacchi V, Dragon-Durey MA, et al;French Society of Pediatric Nephrology. J Am Soc Nephrol. 2007;18:2392-2400. 5. Nester CM, Thomas CP. Hematology Am Soc Hematol Educ Program. 2012;2012:617-625.

Systemic, Complement-Mediated TMA Affects Multiple Vital Organs and Tissues1-16 Renal: More than 50% of patients progress to ESRD1 Elevated creatinine2,3 Proteinuria4 Oedema,3 malignant hypertension5 Decreased eGFR6 CNS: Up to 48% of patients experience neurological symptoms4 Confusion7 Stroke7 Encephalopathy5 Seizure4 Blood: Thrombocytopenia1 Decreased haptoglobin1 Elevated LDH1 Decreased haemoglobin1 Schistocytes1 Visual: Ocular occlusion8 Cardiovascular: Up to 43% of patients experience cardiovascular symptoms4 Myocardial infarction9,16 Hypertension10 Diffuse vasculopathy6 Peripheral gangrene11,16 Gastrointestinal: 37% of patients experience GI symptoms12 Diarrhoea13 Colitis7 Nausea/Vomiting14 Pancreatitis14 Abdominal pain7 Gastroenteritis5 Liver necrosis6 Pulmonary: Dyspnea9 Pulmonary haemorrhage15 Pulmonary oedema9 A full clinical assessment should evaluate multiple organ systems References: 1. Caprioli J, Noris M, Brioschi S,et al; for the International Registry of Recurrent and Familial HUS/TTP. Blood. 2006;108:1267-1279. 2. Ariceta G, Besbas N, Johnson S, et al; for the European Paediatric Study Group for HUS. Pediatr Nephrol. 2009;24:687-696. 3. Ståhl A-L, Vaziri-Sani F, Heinen S, et al.. Blood. 2008;111:5307-5315. 4. Neuhaus TJ et al. Arch Dis Child. 1997;76:518-521. 5. Noris M et al. Clin J Am Soc Nephrol. 2010; 5:1844-1859. 6. Loirat C et al. Pediatr Nephrol. 2008;23:1957-1972. 7. Ohanian M et al. Clin Pharmacol. 2011;3:5-12. 8. Larakeb A et al. Pediatr Nephrol. 2007;22:1967-1970. 9. Sallée M et al. Nephrol Dial Transplant. 2010;25:2028-2032. 10. Kavanagh D et al. Med Bull. 2006;77-78:5-22. 11. Malina M et al. Pediatr Nephrol. 2011;26:1678. 12. Langman C. Haematologica. 2012;97(s1):195-196. 13. Zuber J et al. Nat Rev Nephrol. 2011;7:23-35. 14. Dragon-Durey M-A et al. J Am Soc Nephrol. 2010;21:2180-2187. 15. Sellier-Leclerc A-L al; French Society of Pediatric Nephrology. J Am Soc Nephrol. 2007;18:2392-2400. 16. Noris M and Remuzzi G Nat Rev Nephrol. 2014;10(3):174-80.

Complement-Amplifying Conditions Place Patients with aHUS at High Risk for TMA Manifestations

More Frequent Conditions Less Frequent Conditions Complement-Amplifying Conditions Place Patients with aHUS at High Risk for Unpredictable TMA Manifestations1-4 Complement amplification occurs frequently and is not always apparent2,5-7 More Frequent Conditions Less Frequent Conditions Diarrhoea/Gastroenteritis Bacterial, viral, and fungal infections Atherosclerosis Pregnancy-associated Surgeries Allergies Asthma Anaphylactic shock Malignant Hypertension Transplant-Associated Inflammatory Bowel Disease Glomerulopathy Systemic Disease* Malignancy Thyroiditis *Systemic Lupus Erythematosus or Scleroderma. References: 1. Noris M, Mescia F, Remuzzi G. Nat Rev Nephrol. 2012;8:622-633. 2. Liszewski MK, Atkinson JP. Hematology Am Soc Hematol Educ Program. 2011;2011:9-14. 3. Fang CJ, Richards A, Liszewski MK, et al. Br J Haematol. 2008;143:336-348. 4. Campistol JM, Arias M, Ariceta G, et al. Nefrologia. 2013;33:27-45. 5. Hirt-Minkowski P, Dickenmann M, Schifferli JA. Nephron Clin Pract. 2010;114:c219-c235. 6. Ricklin D, Hajishengallis G, Yang K, et al. Nat Immunol. 2010;11:785-797. 7. Wagner E, Frank MM. Nat Rev Drug Discov. 2010;9:43-56.

aHUS can be Unmasked by Complement-Amplifying Conditions1 Complement-amplifying conditions present a situation where aHUS can be identified in patients who may otherwise go undiagnosed1 Patients with aHUS are particularly susceptible to TMA when experiencing a complement-amplifying condition2-6 Amplification of complement in patients with aHUS can upregulate the complement cascade beyond the patient’s ability to regulate References: 1. Noris M, Caprioli J, Bresin E, et al. Clin J Am Soc Nephrol. 2010;5:1844-1859. 2. Noris M, Mescia F, Remuzzi G. Nat Rev Nephrol. 2012;8:622-633. 3. Frémeaux-Bacchi V, Fakhouri F, Garnier A, et al. Clin J Am Soc Nephrol. 2013;8:554-562. 4. Liszewski MK, Atkinson JP. Hematology Am Soc Hematol Educ Program. 2011;2011:9-14. 5. Fang CJ, Richards A, Liszewski MK, et al. Br J Haematol. 2008;143:336-348. 6. Campistol JM, Arias M, Ariceta G, et al. Nefrologia. 2013;33:27-45.

69% of Patients with aHUS Showed their First Clinical Manifestation While Experiencing One of the Following Complement-Amplifying Conditions (N=191*)1 More Frequent Conditions Less Frequent Conditions Diarrhoea/ Gastroenteritis 24% Upper respiratory tract infections 18% Malignant hypertension 8% Pregnancy Associated 7% Malignancy 1% Others 12% Footnotes: *Patients with non-familial aHUS **E.g., Systemic Lupus Erythematosus and Scleroderma. Reference: 1. Noris M, Caprioli J, Bresin E, et al. Clin J Am Soc Nephrol. 2010;5:1844-1859.

aHUS Can Be Unmasked by Pregnancy-Associated Complement Amplification

aHUS Associated with Pregnancy Can Lead to Significant and Rapid Onset of Renal Damage1 21% (21/100) of female patients with aHUS presented with TMA during pregnancy or post-partum in a national aHUS registry1 81% (17/21) of patients required haemodialysis1 62% (13/21) of female patients with aHUS reached ESRD within the first month after TMA manifestation1 Patients with ESRD Reference: 1. Fakhouri, et al. Pregnancy-Associated haemolytic uraemic Syndrome Revisited in the Era of Complement Gene Mutations. J Am Soc Nephrol 2010.

Chronic, Uncontrolled Complement Activity Resulting From aHUS is a Known Cause of Pregnancy-Associated TMA1-2 aHUS shared common clinical features with other pregnancy- associated complications and may be underdiagnosed aHUS complement mutations have been identified in 5-15% of preeclampsia cases and in a higher percentage of HELLP cases1 aHUS is commonly unmasked post-partum, while TMA due to severe ADAMTS13 deficiency occurs more often during pregnancy2 79% of the pregnancy-associated aHUS diagnoses presented in the post-partum period2 History of a normal first pregnancy does not exclude a diagnosis of aHUS2 57% (12/21) of patients first presented with aHUS unmasked during a second or subsequent pregnancy2 Reference: 1. Liszewski MK, Atkinson JP. Hematology Am Soc Hematol Educ Program. 2011;2011:9-14. 2. Fakhouri, et al. Pregnancy-Associated haemolytic uraemic Syndrome Revisited in the Era of Complement Gene Mutations. J Am Soc Nephrol 2010.

Malignant Hypertension (MHT) aHUS Can Be Unmasked by Malignant Hypertension (MHT)

Chronic, Uncontrolled Complement Activity Resulting from aHUS is a Known Cause of TMA in Patients with MHT1-2,5 Patients with severe or malignant hypertension and with an underlying complement mutation for aHUS are at high risk of TMA1-4 In MHT, complement activity can be amplified due to endothelial damage caused by shear stress and vasoconstriction5 TMA in patients with MHT or severe hypertension is associated with severe end organ damage6 86% of patients with MHT/severe hypertension and TMA did not recover normal renal function despite receiving antihypertensives in a retrospective analysis of 21 patients6 MHT is also a known complication of aHUS2,7,8 Reference: 1. Noris M, et al. Clin J Am Soc Nephrol. 2010 2. Nadar SK, et al. J Human Hypertens. 2007; 21:261-263. 3. Totina A, et al. Clin Pediatr (Phila.). 2011;52:183-186. 4. Noris M, et al. Nat Rev Nephrol. 2012;8:622-633. 5. Shibagaki Y, et al. Hypertens Res. 2005:28:89-95. 6. Zhang B et al. Hypertens Res. 2008;31(3):479-483. 7. Geerdink LM, et al. Pediatric Nephrol. 2012;27:1283-1291. 8. Barbour T, et al. Nephrol Dial Transplant. 2012;27:2673-2685.

aHUS: Early Diagnosis is Critical to Improve Patient Outcomes

Definition of aHUS Signs and symptoms of complement-mediated TMA1 Decreased platelet count Evidence of microangiopathic haemolysis Evidence of organ impairment/damage (e.g. serum creatinine >ULN) Differentiate from other TMA diseases1 ADAMTS13 Activity >5% → excludes severe ADAMTS13 deficiency (congenital or acquired TTP) Absence of positive STEC test → excludes STEC as sole cause of TMA No requirement for identified complement gene mutation Genetic mutation cannot be identified in 30%-50% of patients with aHUS2,3 References: 1. Laurence J. Clin Adv Hematol Oncol. 2012;10 (10 Suppl 17):1-12. 2. Kavangh D et.al Hematology Am Soc Hematol Educ Program. 2011;2011:15-20 3. Kavanagh D et al. British Medical Bulletin. 2006; 77 and 78: 5-22.

Challenges in Diagnosing aHUS Clinical presentation can be similar to other systemic TMAs1 Complement-amplifying conditions may unmask aHUS2,4 Historical supportive care did not require differential diagnosis between aHUS, TTP, and STEC-HUS – historically grouped as TTP/HUS1,3 aHUS is a rare disease, leading to lack of clinical suspicion4 Advancements in management options warrant early diagnosis and intervention1,5 References: 1. Laurence J. Clin Adv Hematol Oncol. 2012;10 (10 Suppl 17):1-12. 2. Noris M et al. N Engl J Med. 2009;361:1676-1687. 3 Ariceta G et al. European Paediatric Study Group for HUS. Pediatr Nephrol. 2009;24:687-696. 4. Kavanagh D et al. British Medical Bulletin. 2006; 77 and 78: 5-22. 5. Legendre CM, Licht C, Muus P, et al. N Engl J Med. 2013;368:2169-2181.

Differential Diagnosis for TMAs: aHUS, TTP and STEC-HUS Thrombocytopenia1,2 Platelet count <150 x 109/L OR >25% Decrease from baseline1 Microangiopathic Hemolysis2,3 Schistocytes2,3 and/or Elevated LDH2 and/or Decreased haptoglobin2 and/or Decreased haemoglobin2 AND AND Plus 1 or more of the following: Neurological Symptoms4-7 Confusion4,5 and/or Seizures6 and/or Other cerebral abnormalities5 Renal Impairment2,9,10 Elevated creatinine10 and/or Decreased eGFR2,10 and/or Elevated blood pressure11 and/or Abnormal urinalysis9 Gastrointestinal Symptoms2,6,12 Diarrhea +/– blood12 and/or Nausea/vomiting6 and/or Abdominal pain6 and/or Gastroenteritis2,12 Evaluate ADAMTS13 activity and Shiga-toxin/EHEC* test8,13–15 While waiting for ADAMTS13 results, a platelet count >30 x109/L or serum creatinine >150–200 µmol/L (>1.7–2.3 mg/dL) almost eliminates a diagnosis of severe ADAMTS13 deficiency (TTP)16,17 A patient with a TMA presenting with SCr >1.7 mg/dL OR platelet count >30 x 109/L is less likely to have severe ADAMTS13 deficiency (TTP) than those who meet neither criteria 1,17 This pathway is intended as educational information for healthcare providers. It does not replace a healthcare professional’s judgment or clinical diagnosis. Footnotes: *Shiga-toxin/EHEC test is warranted with history/presence of GI symptoms. References: 1. Data on file. Alexion Pharmaceuticals, Inc. 2. Caprioli J et al. Blood. 2006;108(4):1267-1279. 3. Noris M et al. NEJM. 2009;361:1676-1687. 4. Neuhaus et al. Arch Dis Chilid. 1997;76:518-521. 5. Noris M et al. JASN. 2005;16:1177-1183. 6. Dragon-Durey et al. J Am Soc Nephrol. 2010;21:2180-2187. 7. Davin et al. Am J Kid Dis. 2010;55:708-777; 8. Bianchi et al. Blood. 2002;110:710-713. 9. Al-Akash et al. Pediatr Nephrol. 2011;26:613-619. 10. Sellier-Leclerc AL. JASN. 2007;18:2392-2400. 11. Benz et al. Curr Opin Nephrol Hypertens. 2010;19:242-247. 12. Noris M et al. Clin J Am Soc Nephrol. 2010;5:1844-1859. 13. Tsai H-M. Int J Hematol. 2010;91:1-19; 14. Barbot et al. Br J Haematol. 2001;113:649. 15. Bitzan M. Semin Thromb Hemost. 2010;36:594-610. 16. Zuber J et al. Nat Rev Nephrol. 2012;8:643-657. 17. Coppo P, Schwarzinger M, Buffet M, et al. PLOS ONE. 2010;5:e10208.

Differential Diagnosis for TMAs: aHUS, TTP and STEC-HUS Thrombocytopenia1,2 Platelet count <150 x 109/L OR >25% Decrease from baseline1 Microangiopathic Hemolysis2,3 Schistocytes2,3 and/or Elevated LDH2 and/or Decreased haptoglobin2 and/or Decreased haemoglobin2 AND AND Plus 1 or more of the following: Neurological Symptoms4-7 Confusion4,5 and/or Seizures6,8 and/or Other cerebral abnormalities5 Renal Impairment2,9,10 Elevated creatinine10 and/or Decreased eGFR2,10 and/or Elevated blood pressure11 and/or Abnormal urinalysis9 Gastrointestinal Symptoms2,6,12 Diarrhea +/– blood12 and/or Nausea/vomiting6 and/or Abdominal pain6 and/or Gastroenteritis2,12 Evaluate ADAMTS13 activity and Shiga-toxin/EHEC* test8,13–15 While waiting for ADAMTS13 results, a platelet count >30 x109/L or serum creatinine >150–200 µmol/L (>1.7–2.3 mg/dL) almost eliminates a diagnosis of severe ADAMTS13 deficiency (TTP)16,17 ≤5% ADAMTS13 Activity8,13,14 >5% ADAMTS13 Activity8,12-14 Shiga-toxin/EHEC Positive15 TTP aHUS STEC-HUS This pathway is intended as educational information for healthcare providers. It does not replace a healthcare professional’s judgment or clinical diagnosis. Footnotes: *Shiga-toxin/EHEC test is warranted with history/presence of GI symptoms. References: 1. Data on file. Alexion Pharmaceuticals, Inc. 2. Caprioli J et al. Blood. 2006;108(4):1267-1279. 3. Noris M et al. NEJM. 2009;361:1676-1687. 4. Neuhaus et al. Arch Dis Chilid. 1997;76:518-521. 5. Noris M et al. JASN. 2005;16:1177-1183. 6. Dragon-Durey et al. J Am Soc Nephrol. 2010;21:2180-2187. 7. Davin et al. Am J Kid Dis. 2010;55:708-777; 8. Bianchi et al. Blood. 2002;110:710-713. 9. Al-Akash et al. Pediatr Nephrol. 2011;26:613-619. 10. Sellier-Leclerc AL. JASN. 2007;18:2392-2400. 11. Benz et al. Curr Opin Nephrol Hypertens. 2010;19:242-247. 12. Noris M et al. Clin J Am Soc Nephrol. 2010;5:1844-1859. 13. Tsai H-M. Int J Hematol. 2010;91:1-19; 14. Barbot et al. Br J Haematol. 2001;113:649. 15. Bitzan M. Semin Thromb Hemost. 2010;36:594-610. 16. Zuber J et al. Nat Rev Nephrol. 2012;8:643-657.

Patient/Family Medical History Patient and Family Medical History May Help Determine if aHUS is the Underlying Cause of TMA1 Patient/Family Medical History History of previous TMA Unexplained renal failure Malignant/severe hypertension Unexplained MI Preeclampsia with renal involvement that persisted after pregnancy 1. Noris M, et al. Clin J Am Soc Nephrol. 2010

No Requirement for Genetic Testing in the Diagnosis of aHUS Genetic mutation cannot be identified in 30%-50% of patients with aHUS1,2 No requirement for identified complement gene mutation Results generally take weeks to months – therefore, does not impact initial clinical management Regardless of whether or not a mutation is identified, patients with aHUS have similarly devastating outcomes3 References: 1.Kavangh D et.al Hematology Am Soc Hematol Educ Program. 2011;2011:15-20 2.Kavanagh D et al. British Medical Bulletin. 2006; 77 and 78: 5-22. 3. Noris M, et al. Clin J Am Soc Nephrol. 2010;5:1844-1859

No Requirement for Complement Level Testing in the Diagnosis of aHUS Complement and soluble complement regulatory protein levels in plasma or serum are unreliable in the diagnosis of aHUS1,2 Majority of aHUS patients have normal levels of complement2 Serum C3 – normal in approximately 80% of aHUS patients References: 1. Noris M, et al. Clin J Am Soc Nephrol. 2010;5:1844-1859. 2. Laurence J. Clin Adv Hematol Oncol. 2012;10 (10 Suppl 17):1-12.

Historical Supportive Care Options Limitations of Historical Supportive Care Options

Historical Supportive Care Options for aHUS Fail to Address Underlying Chronic Uncontrolled Complement Activity1-13 PE/PI Serious complications in children (55%) and adults (15%)1 26% of all patients experience major complications, including death, systemic infection, thrombosis, and pulmonary haemorrhage2 Dialysis The overall five-year mortality rate for dialysis and peritoneal dialysis patients was 54%3 Does not protect patients from serious, extra renal morbidities, including thrombocytopenia, haemolysis, cerebral ischemic events, ocular damage, peripheral gangrene, vascular stenoses and arterial steno-occlusive lesions4-8 Kidney Transplant9,10 Liver Kidney Transplant High risk of morbidity and mortality11 Antihypertensives12,13 Packed Red Blood Cell Transfusions12,13 References: 1. Zuber J et al. Nat Rev Nephrol. 2012;8:643-657. 2. Nguyen L et al. Transfusion. 2009;49:392-394. 3. Australian Institute of Health and Welfare. Dialysis and kidney transplantation in Australia: 1991–2010. Cat. no. PHE 162. Canberra: AIHW.4. Neuhaus TJ et al. Arch Dis Child. 1997;76:518-521. 5. Malina M et al. Pediatr Nephrol. 2011;26:1678. 6. Larekeb A et al. Pediatr Nephrol. 2007;22:1967-1970; 7. Remuzzi G et al. Am J Transplant. 2005;5:1146-1150. 8. Vergouwen MDI et al. AJNR Am J Neuroradiol. 2008;29:e34. 9. Bresin E et al. International Registry of Recurrent and Familial HUS/TTP. Clin J Am Soc Nephrol. 2006;1:88-99; 10. Davin JC et al. Am J Kidney Dis. 2010;55:708-711. 11. Saland, New York - 5 cases; Lorait 2011 Orphanet; Zuber 2012, and Nester. 12. Ariceta G et al. Pediatr Nephrol. 2009;24:687-696. 13. Waters AM et al. Pediatr Nephrol. 2011;26:41-57.

Summary In aHUS, 79% of patients die, require dialysis, or have permanent renal damage within 3 years1 33 to 40% of patients die or progress to end-stage renal disease with the first clinical manifestation, despite PE/PI1,2 Chronic, uncontrolled complement activity results in continuous endothelial and tissue injury Complement amplification is common, unpredictable and puts patients at constant risk of sudden death and multi-organ damage aHUS should be suspected in patients presenting with both a complement-amplifying condition and TMA ADAMTS13 activity, serum creatinine levels and platelet count can be used to exclude a diagnosis of severe ADAMTS13 deficiency (TTP) Advancements in treatment options warrant early diagnosis and ongoing intervention References: 1. Noris M, Caprioli J, Bresin E, et al. Clin J Am Soc Nephrol. 2010;5:1844-1859. 2. Caprioli J, Noris M, Brioschi S, et al; for the International Registry of Recurrent and Familial HUS/TTP. Blood. 2006;108:1267-1279.

aHUS Registry Registry Inclusion Criteria Exclusion Criteria Observational, non-interventional, multinational Patients with a diagnosis of aHUS, regardless of treatment, will be eligible for enrollment after providing written, informed consent Inclusion Criteria Male or female patients of any age, including minors, who have been diagnosed with aHUS Diagnosis of aHUS includes: Clinical diagnosis of aHUS Patients with or without an identified complement regulatory factor genetic abnormality or anti-complement factor antibody Exclusion Criteria Patients with haemolytic uraemic syndrome (HUS) only due to Shiga-toxin are excluded © 2015 Alexion Pharmaceuticals Australasia Pty Limited. All rights reserved. Alexion Pharmaceuticals Australasia Pty Limited. ACN 132 343 036. Suites 401, Level 4, Building A, 20 Rodborough Road Frenchs Forest NSW 2086. September 2015 AU/DaHUS/15/0017