Benign Hematology Update: ASH, ISTH, and the Literature 2013

1. Benign Hematology Update:ASH, ISTH, and the Literature 2013 Craig M Kessler, MD, MACP Professor of Medicine and Pathology Lombardi Comprehensive Cancer Center Georgetown University Medical Center Washington, DC

2. Disclosures • Research- Amgen, Baxter, Bayer, Biogen, Eisai, Grifols, NovoNordisk, Octapharma • Advisory Boards-Amgen, Baxter, Bayer, Biogen, Eisai, Grifols, NovoNordisk, Octapharma • Stock- Not applicable • Employment – Not applicable • Speakers’ Bureau – Not applicable

3. Topics • Autoimmune thrombocytopenia • Target specific oral anticoagulation • Duration of anticoagulation for VTE • New developments in von Willebrand disease • Advances in the treatment of sickle cell anemia • Miscellaneous

4. Pathophysiology of Immune Thrombocytopenic Purpura • Phagocyte-mediated accelerated clearance of antiplatelet AB coated platelets in the RES • Dysregulated T-cell function • Direct cytotoxicity against megakaryocytes and platelets • T-helper cell support for biosynthesis of Abs by B-cells • Abnormal number and function of T-regs • Suboptimal platelet production

5. What is the best approach to corticosteroids for de novo ITP? Abs 325: A Randomized Trial Of Daily Prednisone Versus Pulsed Dexamethasone In Treatment of Naïve Patients With Idiopathic Thrombocytopenic PurpuraMatsche J et al Week 1: All pts received prednisone (1 mg/kg/d) followed by a 1:1 randomization between daily prednisone and pulsed dexamethasone Prednisone given at 1 mg/kg/d; after remission dose tapered 19 weeks to maintenance dose ≤ 25 mg/d at wk 13 and < 7.5 mg/d at wk 19 If no remission at 2 wks, prednisone increased to 2 mg/kg/d for another 2 weeks. If remission, tapered as above (≥ 50K platelets) Dexamethasone given q 3 wks for 6 courses (0.6 mg/kg day 1 to 4) Failure to achieve a remission: pts crossed over to the alternative treatment Prednisone: no remission after 4 wks at 1-2 mg/kg/d Dexamethasone: no remission after two cycles

6. Abs 325: A Randomized Trial Of Daily Prednisone Versus Pulsed Dexamethasone In Treatment of Naïve Patients With Idiopathic Thrombocytopenic PurpuraMatsche J et al No statistically significant difference in time to remission (p=0.55) Remission duration significantly longer with dex vs prednisone (p=0.0139) Median tx duration = 85 d (range: 28 – 153) for pred; Median tx cycles 5 (range: 3 – 7) for dex Median cumulative cortisol equivalent dose = 15.780 mg for pred; and 34.560 mg for dex No difference in Grade 3 or 4 bleeding events No difference in Grade 3 or 4 adverse events: 1 pt on pred (hypertension) and 2 pts on dex (hyperglycemia, hypokalemia). Remission duration (platelets >50x109/l) in ITP pts receiving daily prednisone versus pulsed dexamethasone

7. Suppression of Megakaryocyte Maturation and Platelet Production by ITP Plasma 100 75 % Control Megakaryocytes 50 25 0 ITP-1 ITP-2 ITP-3 ITP-4 ITP-5 ITP-6 ITP-7 ITP-8 ITP-9 ITP-10 ITP-11 ITP-12 Heterogeneous responses in vitro: Anti-platelet ABs affect megakaryocytes and circulating platelets McMillan R, et al. Blood. 2004;103:1364-1369.

8. How Does Rituximab Affect ITP Outcome? Abs 449: Rituximab As Second Line Treatment For Adult Immune Thrombocytopenia (ITP): A Multicentre, Randomized, Double Blind, Placebo-Controlled Study – The Ritp Study Ghanima W et al • First randomized placebo-controlled, double blind study to assess both short and long-term efficacy and safety of RTX in steroid-unresponsive ITP • Ptsrandomized to 4 weekly infusions of 375mg/m2 RTX or placebo • Steroids allowed throughout the study • Main inclusion criteria: • 1- unsplenectomized with primary ITP; platelets <30K • 2- failure to achieve sustained response to 1-2 mg/kg prednisone given > 2 wks or relapse during steroid-tapering/discontinuation

9. Abs 449: Rituximab As Second Line TreatmentFor Adult Immune Thrombocytopenia (ITP): A Multicentre, Randomized, Double Blind, Placebo-Controlled Study – The Ritp Study Ghanima W et al Per Cent of Patients NOT Achieving Complete Response • RTX did not reduce the rate of overall treatment failure • Lower rate of splenectomy in the RTX-arm • RTX induced significantly higher rate of CR at 24 wks Time to Complete Response (days) ▬ Placebo ▬ Rituximab

10. Do TPO-RAs Enhance Rituximab Effectiveness? Abs 329: Recombinant Human TPO and Rituximab vs Rituximab Monotherapy in Corticosteroid-Resistant Primary ITP: a Multicenter Randomized Controlled Study Xiu M et al Characteristics and result of RTX group and rhTPO plus RTX Kaplan-Meier plot of time to relapse in patients achieving response or complete response • RTX + rhTPO yields shorter time to response vs RTX only • Combination extended time to relapse

11. Thrombopoietin (TPO): Properties and Pertinent Facts • TPO = c-mpl ligand; c-mpl = TPO receptor • c-mpl is the murine retroviral oncogene causing a “myeloproliferative leukemia (mpl)” in mice • c-mpl found in platelets and megakaryocytes • TPO gene on human chromosome 3 • TPO is synthesized predominantly by hepatocytes • TPO mRNA also found in kidney, marrow, and brain-? Hematopoietic importance

12. TPO affects viability of early progenitors of all lineages but affects the late maturation only of megas: TPO only stimulates production of platelets but not RBCs or WBCs Increasing ploidy The Oncologist January 1, 2009 vol. 14 no. 1 12-21

13. Normal Levels Increased Levels The Physiological regulation of TPO levels Kuter DJ. The Oncologist 1996, 1:98-106.

14. Endogenous TPO Concentrations Are Minimally Elevated in ITP Patients Nichol J. In: Kuter DJ et al, eds. Thrombopoiesis and Thrombopoietins: Molecular, Cellular, AA, aplastic anemia

15. Can Serum TPO Levels Predict Response to TPO mimetics? 21 patients with ITP (ELISA, R&D Systems, Minn, MN). Serum TPO levels >95 pg/mL predicts for reduced and less durable responses to TPO receptor agonists in ITP patients = inadequate megakaryopoiesis as basic pathology Makar, R. S., et al. Am. J. Hematol.. doi: 10.1002/ajh.23562

16. AMG 531: Mechanism of Action ThrombopoietinReceptor AMG 531 Active Receptor Inactive Receptor Cell Membrane SHC GRB2 RAS/RAF SOS P P P JAK STAT P Cytoplasm MAPK Promotion of cell growth Potentiate maturation p42/44 Signal Transduction Increased Platelet Production Anti-apoptosis Kuter DJ. Int J Hematol (2013) 98:10–23

17. Practical Considerations for Romiplostim • T1/2 = 120 – 140 hours whether IV or SQ • Not formulated for IV use • T1/2 not affected by renal or hepatic function • Not recommended during pregnancy since can cross placental barrier via FcRn receptor • Pregnancy registry- ? Safety with breastfeeding • Start at 1 µg/Kg/wk; titrate up to 10 µg/Kg/wk • Effective mean dose in most studies = 4-5 µg/Kg • Do not withhold dose → precipitous nadirs • Dose reduce 25-50% for >400K platelets

18. Eltrombopag (SB497115): Mechanism of Action ThrombopoietinReceptor Eltrombopag Active Receptor Inactive Receptor Cell Membrane SHC GRB2 RAS/RAF SOS P P P JAK STAT P Cytoplasm MAPK Promotion of cell growth Potentiate maturation p42/44 Signal Transduction Anti-apoptosis Increased Platelet Production Kuter DJ. Int J Hematol (2013) 98:10–23

19. Pharmacologic Considerations for Eltrombopag • Activates signal transduction pathways differently than TPO or romiplostim • Weaker stimulator of JAK and STAT phosphorylation • Does not activate AKT pathway at all, unlike TPO or romiplostim • Eltrombopag effect is additive to TPO in vitro. ? In vivo significance Growth of TPO-dependent cell line Kuter DJ. Internat J Hematology. 2013;98(1):10-23

20. Long-term safety and tolerability of romiplostim in ITP: Pooled analysis of 13 clinical trials (653 patients) All received ≥ 26 wks tx; all 8- 18 µg/kg/wk; 5/13 > 10µg/kg/wk (Baseline cytogenetics consistent with MDS) (PMF) HM=hematological malignancies: • Rom-CLL, AML, lymphoma (2), MPN • SOC/placebo: lymphoma, MDS HM = Hematologic malignancies Rodeghiero F et al. Eur J Haematol 2013;91(5) doi:10.1111/ejh.12181

21. Can Patients Eventually Discontinue TPO Agonists? Abs 327: Prolonged Remission After TPO-Receptor Agonist Discontinuation In Adults With Chronic ITP. Results Of a French Observational Study Mahévas M et al. • Romiplostim & eltrombopag: 70-80% lasting response-rate in long-term studies • Platelets ↓ to baseline or lower within 10 d post TPO-RA withdrawal in majority of cases • 54 pts (35 females) studied: 46 (85%) with chronic; 8 (15%) with newly-diagnosed ITP Median of 4 treatment-lines (rituximab in 59%; splenectomy in 33%) 18 received eltrombopag; 22 romiplostim; 14 received both TPO-RAs sequentially • Overall response rate on TPO-RA: 81.5%; CR (51.8%); PR (29.6%) • In 20 out of 28 pts achieving a CR, TPO-RA was discontinued after median 10 mos (1-70) Among the 14 evaluable pts: 6 (30%) relapsed within 10 d, requiring rescue therapy 8 pts (70%) with CR over median follow-up of 13.5 mos (range: 5-27) • No predictors of sustained response (age, gender, duration of ITP, previous types/number of therapies before TPO-RA) • Summary: 15 % pts treated with TPO-RA achieve a durable response after treatment discontinuation. A prospective trial is needed

22. Thrombotic Events in Adult ITP:Metaanalysis • Estimated frequency of thromboembolism: • 3.1% (95% CI, 1.8-4.4%) for TPOr agonists • 1.7% (95% CI, 0.3-3.1%) for controls • TPOr agonists show a numerically but non-statistically significant trend to increase the occurrence of thromboembolic events • Underpowered • Use of IVIg, ASA, splenectomy not accounted for Catala-Lopez F et al. Med Clin (Barc). 2012 Oct 20;139(10):421-9. doi: 10.1016/j.medcli.2011.11.023. Epub 2012 Jan 23

23. Novel Approaches to the Treatment of ITP • Oral Syk inhibitor R788 • Syk is downstream signal transduction regulator of monocyte and macrophage phagocytosis • Blockage of Syk pathway hypothetically should inhibit platelet destruction • Pilot study (N=16), 50% ITP pats demonstrated sustained platelet counts >50K 1 • Anti-CD40 ligand • CD40L is critical for T-cell-dependent B-cell expansion; autoreactive CD4+ T-cells increased in ITP • IDEC-131 and hu5c8 (anti-CD40L monoclonal AB) had overall response rate of 13-16% 2 1. Podolanczuk A et al. Blood.2009;113:3154; 2. Patel VL et al. Br J Haematol.2008;141:545

24. Clinical Comparisons of the Novel Oral Anti-Xa Anticoagulants In clinical development: Betrixaban(not FDA approved)

26. Edoxaban • Oral direct factor Xa inhibitor with a rapid onset of action and half-life of 10–14 hours • 60 mg once daily dose was selected based on phase II data • Dose of 30 mg in case of • moderate renal impairment (CrCl 30 - 50mL/min) • low body weight, i.e., ≤ 60 Kg • concomitant use of P-gp inhibitors

27. Aim: To evaluate whether initial (LMW)heparin followed by edoxaban only is non-inferior to initial (LMW)heparin overlapping with warfarin, followed by warfarin only in the treatment of subjects with acute symptomatic venous thromboembolism for the prevention of symptomatic recurrent venous thromboembolism during a 12-month study period edoxaban Sham INR Symptomatic confirmed VTE event R INR warfarin Day 1- 5 Day 6- 12 12 M 3 M 6 M initial (LMW)Heparin placebo warfarin placebo edoxaban

28. Efficacy outcomes * Denominator is number of patients with index DVT: 2468 and 2453 in edoxaban and warfarin grouprespectively ** Denominator is number of patientswith index PE : 1650 and 1669 in edoxaban and warfarin grouprespectively

29. Safety outcomes † some patients have more than 1 bleeding

30. Principal Safety Outcome Number of patients at risk

31. Baseline characteristics

32. Abs 211: Edoxaban For Long-Term Treatment Of Venous Thromboembolism In Cancer Patients • 771 CA pts enrolled (208 with active cancer/563 with CA history) • Median duration of tx for edox = 267 d vs 266 d for warf (180 to 360 d in both groups) • Recurrent VTE in active CA pts: 3.7% in edox; 7.1% in warf (HR 0.55) • Clinically relevant bleeding in 18.3% on edox (major= 4.6%) vs 25.3% on warf (major = 3.0%) (HR = for clinically relevant bleeding 0.72) • For non-CA pts: recurrent VTE = 2.8% for edox; 2.7% for warf (HR = 1.03) • For non-CA pts: relevant bleeding = 7.7% on edox; (1% major); 9.1% on warf (1.3% major) (HR = 0.83) • Edoxaban is as effective, and possibly more effective, than warfarin in CA pts with VTE • Bleeding is appreciable during anticoagulant therapy, but may be less with edox than warf in CA pts • Need additional studies of edox for longer duration and vs LMWH alone rather than warf

33. Venous Thromboembolism Prevention in High Risk Cancer Outpatients % VTE in the anticoagulant & placebo arms of SAVE-ONCO and PROTECHT: Full population versus high-risk subgroups (risk score ≥3) J Natl Compr Canc Network. 2013;11:1435

34. Predictive Scoring Identifies High Risk CA Patients Who May Benefit from VTE Prophylaxis

35. Abs 580: Randomized Controlled Trial Of Dalteparin For Primary Thromboprophylaxis For Venous Thromboembolism (VTE) In Patients With Advanced Pancreatic Cancer (APC): Risk Factors Predictive Of VTE Vadhan-Raj S et al Table: Predictors of VTE (multivariate logistic regression) 85 ambulatory pts with locally advanced or metastatic CA and active chemotx N=38 (dalteparin 5000 U sq/d for 16 wks during chemotx) N=37 (placebo) VTE: 22% placebo vs 5% dalteparin p=0.02 (75% reduction in VTE) No major bleeds w/dalteparin D-dimer >5000 ng/ml predicts baseline incidental VTE OR = 1.40, for every 500 unit increase from baseline D-dimer level

36. Abs 458: Genome-Wide Association Study (GWAS) Of Venous Thromboembolism (VTE) In African-Americans From The Electronic Medical Records & Genomics (eMERGE) Network Heit JA et al • Background:  Incidence of VTE in AAs ≥ Caucasians of European ancestry • Carrier frequencies of inherited thrombophilias common in whites (i.e., Factor V Leiden, Prothrombin G20210A) are very low in AAs, suggesting that other inherited thrombophilias may be associated with VTE in AAs. • Objective:  To identify SNPs associated with VTE in AAs. • Most significant SNPs assoc with VTE (294 AA VTE/3,661 AA controls) • ITPR3 (inositol 1,4,5-triphosphate receptor type 3) (OR=1.65) • CLEC7A (C-type lectin domain family 7, member A) (OR=2.16) • ITPR3 SNPs associated with coronary artery aneurysm in Kawasaki disease, type 1 diabetes mellitus and other autoimmune disorders • CLEC7A encodes for dectin-1 mutation; dectin-1 mediates formation of neutrophil extracellular traps (NETs).  NETs are thrombogenic (AterioscleroThrombVascBiol 2013;33:147-51).

37. Risk Assessment for Recurrence and Optimal Agents for Extended Treatment of Venous Thromboembolism Agnelli G & Becattini C. American Society of Hematology Education Program. Hematology 2013; 471-477.

38. DURATION OF TREATMENT FOR VTE. It’s now about risk:benefit ratio with continued therapy Points to consider • Long-term use of warfarin ~0.8%/year fatal • Relapses of VTE are each about 10% fatal • Strategy now seems to nibble from each end of risk by identifying those clearly at high risk and those clearly at low risk, thus isolating the group in between while seeking equipoise • No matter how long you treat, with cessation of therapy, the VTE relapse rate asymptotically approaches yet NEVER reaches baseline

40. RECURRENCE RATE OF VTE Baglin, T. Lancet. 2003; 362(9383):523-526.

41. PROLONG Study Palareti G. N Engl J Med. 2006; 355:1780-1789.

42. META-ANALYSIS OF RESIDUAL VEIN THROMBOSIS IDIOPATHIC (UNPROVOKED) DVT Carrier M. J Thromb Haemost. 2011 Mar 7. [Epub ahead of print]

43. CLINICAL TRIALS OF NEW ORAL ANTICOAGULANTS AND ASPIRIN FOR EXTENDED TREATMENT OF VENOUS THROMBOEMBOLISM * Incidence per patient-year Agnelli G et al. New Engl J Med 2013; 368:699-708 Agnelli and colleagues have studied longer term thromboprophylaxis in patients with VTE after 6-12 months of rather routine therapy. Patients (N=2486) were randomized at equipoise to then receive 1) placebo, 2) apixaban 5 mg BID (essentially a therapeutic dose) or apixaban 2.5 mg BID (essentially a prophylactic dose) for 12 months

44. New Concepts in the Laboratory Diagnosis of von Willebrand Disease Interactive Registry on Acquired von Willebrand SyndromeavwsSmall.jpgintreavws.com

45. Abs 331: Critical Importance Of VWF Propeptide (VWFpp) In The Diagnosis Of Type 1 Von Willebrand Disease (VWD) Haberichter SL et al 1. Historically VWFpp was known as VWF:AgII2. A subtype of Type 1 VWD is due to increased clearance of the variant protein; is associated with ultralarge HMW VWF multimers; is due to decreased proteolysis by ADAMTS133. Measurement of VWFpp: helps to establish if low VWF levels are due to decreased synthesis or increased clearance. In the former the VWFpp/VWF:Ag ratio is normal [i.e. close to 1] In the latter, VWFpp/VWF:Ag is increased The VWFpp has a concentration in plasma of 1 µg/ml and a T½ of 2-3 hours whereas the mature VWF protein has a concentration in plasma of 10 µg/ml and a T½ of 8-12 hours Type 1 Vicenza and similar VWF variants with shorted T½ are now classified as Type 1C VWD

46. Racial Genetic Variability Results in Overdiagnosis of VWD in African Americans Flood VH et al. Blood. 2010 July 15; 116(2): 280– VWF:Ag higher in AAs than Caucasions but VWF:RCo are equivalent Exon 28 1472 DH polymorphism on exon 28 are overrepresented in AAs (63% vs 17% in Caucasians) 1472 DH interferes with VWF-ristocetin interactions with GP1b/IX in vitro No in vivo consequence but over dx of VWD

47. Abs 776: GMI 1070: Reduction In Time To Resolution Of Vaso-Occlusive Crisis and Decreased Opioid Use In a Prospective, Randomized, Multi-Center Double Blind, Adaptive Phase 2 Study In Sickle Cell Disease Telen MJ et al GMI 1070 is pan-selectin inhibitor; mice studies indicated importance of selectin from WBCs as mediator of VOC The median time to resolution of the crisis was reduced by 63 hrs in GMI 1070 group The median and mean times to hospital discharge were cut by 84 and 55 hours, respectively. Total opioid use for the GMI 1070 group was reduced 83% Although the differences were large, most only approached statistical significance

48. The Ponatinib Problem: Excellent Efficacy vs Emerging Thrombotic Risks • BCR-ABL inhibitor (and T315I mutation) that also selectively inhibits other tyrosine kinases including FLT3, RET, KIT, and members of the FGFR, PDGFR and VEGFR families of kinases. • Among 267 pts with chronic-phase CML, 56% had a major cytogenetic response (51% of patients with resistance to or unacceptable side effects from dasatinib or nilotinib and 70% of patients with the T315I mutation) (PACE trial NEJM 2013;369;1783-96) (Abs 1498 and 2738) • Serious arterial thrombotic events were observed in 9% of patients over median 15 mos observation • After an additional 13 mos of exposure (after FDA fast track approval), cumulative incidence of serious arterial thrombotic events was 11.8% and of all arterial thrmbotic events=17.1%; • FDA then suspends sales and marketing of drug; reinstated on 12/20 for aggressive or resistant disease only

49. 4020: Cumulative incidences of cardio-vascular events occurring in CP CML pts on Ponatinib or on Nilotinib since TKI initiation and on each TKI Nicolini FE et al for French CML Group Prospective study of CP CML on Ponatinib Historical controls on Nilotinib as first line tx Age matched comparison of arterial events only while on therapy (64 [P] vs 54 yrs [N]; P=NS) For pts on P, 6 were in CHR, 2 in PCyR, 5 in CCyR, 6 pts were in MMR 0.2% arterial clots with Dasatinib therapy (abs 1489 Le Coutre PD et al) Ponatinib induces significant high CV events in 8/19 CP CML pts, after a relatively short period of exposure to this compound as compared to a historical cohort of Nilotinib-treated pts (11/58). The role of prior Nilotinib exposure remains to be determined. These results should promote an extreme vigilance especially in older pts with known CV risk factors that will need to be strictly controlled and monitored. A preventive anti-thrombotic prophylaxis might be useful since Ponatinib initiation. https://ash.confex.com/data/abstract/ash/2013/4/7/Paper_59574_abstract_100379_0.gif

50. 1482 Atherothrombotic Risk and TKIs Treatment In CML Patients: A Role For Genetic Predisposition and  Pro-Inflammatory/Pro-Oxidative Status? (Aprile L et al for Italian Study Centers) • Increased reports of venous and arterial thrombotic complications in CML pts on 2nd generation TKIs The link between pro-inflammatory stimuli and lipid peroxidation triggers accelerated atherogenesis. Enhanced inflammatory milieu observed during nilotinib treatment could be an additional factor of accelerate atherothrombosis.