Acute Promyelocytic Leukaemia

Acute Promyelocytic Leukaemia (APML)

1. Presenters : DR. RENESHA ISLAM DR . MD IMRAN HABIB YEAR-3 RESIDENT (PHASE-B) PAEDIATRIC HAEMATOLOGY & ONCOLOGY BANGABANDHU SHEIKH MUJIB MEDICAL UNIVERSITY (BSMMU) WELCOME T O SEMINAR

2. Case scenerio Jubair , 12 years old boy admitted with the complaints of fever for 1 month, progressive pallor for same duration, Multiple blackish spots on different parts of the body, H/O gum bleeding & malena , H/O blood transfusion. O/E: Moderately pale, Gum swelling, Hepatosplenomegaly was present. On lab investigation: Pancytopenia , D dimer level raised, Fibrinogen level decreased, Bone marrow study : Promyelocyte 60%. Immunophenotype : CD 13- 90%, CD 33- 92%, cMPO - 92%. t (15;17) positive.

3. ACUTE PROMYELOCYTIC LEUKEMIA(APML)

4. Introduction Acute promyelocytic leukemia (APML) is an unique subtype of acute myeloid leukemia in which abnormal promyelocytes predominate. The disease is characterized by a chromosomal translocation involving the retinoic acid receptor alpha(RARA) gene and is distinguished from other forms of AML by its responsiveness to ATRA.

5. History APML was first described in 1957 by a Swedish author, Hillestad, when he reported 3 patients characterized by “ A very rapid fatal course of only a few weeks duration ,” with a white blood cell (WBC) picture dominated by promyelocytes and a severe bleeding tendency. More detailed features of APML were described by Bernard et al in 1959, and the severe hemorrhagic diathesis has been described to disseminated intravascular coagulation (DIC) or hyperfibrinolysis.

6. Epidemiology Acute promyelocytic leukemia (APL), is a distinct subtype of acute myeloid leukemia, represents about 8% - 15% of pediatric APML. The disease occur at any age but patients are predominantly adult or in midlife. Older child and adolescents are the major risk group in case of childhood APML.

7. . Laboratory evidence of DIC is present in 70% to 80% of patients at diagnosis or shortly after. Hemorrhagic events contribute 10% to 15% excess mortality during induction chemotherapy for APML. Morphologically , it is identified as aml-m3 by the French-American-British (FAB) classification.

8. Cytogenetically , APL is characterized by a balanced reciprocal translocation abnormality, t(15;17)(q22;q12); PML-RARA . Currently it is one of the most treatable forms of leukemia with a 12-yr PFS rate, is estimated to be approximately 70%.

9. Record from department of PHO,BSMMU regarding APML (From March 2017 to October 2020) Characteristics N Total number of patients 18 Sex Male 11 Female 07 Age <5 years 3 ≥ 5 years 15 Risk group Standard 4 High 14 Hemorrhagic manifestation Either Cutaneous or mucosal 4 Combined 9 ICH 5 None Outcome Alive and on treatment 9 Death (ICH-2, stroke-1) 5 Loss of contact 4

10. Pathogenesis of APML 18/3/2014 11 APL

11. . In Acute promyelocytic leukemia (APL), there is an abnormal accumulation of immature granulocytes called promyelocytes . APL is characterized a balanced reciprocal translocation abnormality, t(15;17)(q22;q12); PML-RARA, which results in fusion of the retinoic acid receptor (RARA) gene on chromosome 17 with the promyelocytic leukemia (PML) gene on chromosome 15. .

12. 18/3/2014 t(15;17); PML-RARA 13 APL

13. Molecular pathogenesis

14. . The fusion of PML and RARA results in expression of a hybrid protein with altered functions. This fusion protein binds with enhanced affinity to sites on the cell's DNA, blocking transcription and differentiation of granulocytes. Although the chromosomal translocation involving RARA is believed to be the initiating event, additional mutations are required for the development of leukemia.

15. 18/3/2014 17 APL

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17. APML t(15,17)

18. 18/3/2014 20 APL

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20. Fatal coagulopathy in APML APML is special from other leukemia because life threatening bleeding is frequently associated with this type. Reasons are- Procoagulant activity APL cells express two tumor-associated procoagulants : tissue factor (TF) and cancer procoagulant (CP). Cytokines Leukemic promyelocytes secrete various cytokines like IL-1b and TNFa that may mediate APL-associated coagulopathy through various complex mechanisms.

21. . Fibrinolysis Leukemic promyelocytes highly express annexin-II, which may lead to primary fibrinolysis. Annexin-II is a protein receptor with a strong affinity for plasminogen and tPA, which results in greatly increased conversion of plasminogen to plasmin. Proteolysis Proteolysis of clotting factors and fibrinogen by granulocytic proteases such as elastase and chymotrypsin, found in the granules of APML blasts.

22. Presentation Most patients with APML present with pancytopenia. About 10-30% of patients present with leukocytosis . APL differs from AML in that most patients present with coagulopathy. The coagulopathy has been described as disseminated intravascular coagulation (DIC) with associated hyperfibrinolysis . It is important to treat the coagulopathy as a medical emergency. In 40% of untreated patients, pulmonary and cerebral hemorrhages can occur.

23. M3V Microgranular varient of APML characterized by – bilobed cells, multilobed cells or cells with reniform nucleus and cytoplasm with minimal or no granulation associated with few typical M3 cells. Presents with- Hyperleukocytosis Severe coagulopathy, fatal hemorrhage. Poor prognosis.

24. Diagnosis of APL

25. Diagnosis of APL Clinical Morphological Immunophenotyping Molecular genetics Cytogenetics

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27. Investigation CBC with PBF: pancytopenia Hyperleucocytosis – bad prognosis PBF: presence of blasts. Bone marrow study: -morphology - Immunophenotyping RT-PCR: - Can detect minimal residual disease (MRD). - “Gold Standard”.

28. Bone marrow study Morphology : predominant promyelocytes. Immunophenotype: CD33- Bright expression. CD13-Heterogenous expression. cMPO – Always strongly positve. CD34- Low expression or absent. HLA-DR – Low expression or absent. Cytogenetics: t(15,17) in 95% cases, rest 5% are t(5,17) and t(11,17). ,

29. Biochemical Coagulation profile : PT, APTT, FDP, D-dimer, fibrinogen CXR, CSF study S.ALT, S. Creatinine S. LDH S. Uric acid S. Inorg. Phosphate S. Calcium RBS S. Electrolytes Echo, ECG

30. Anti-PML Immunofluorescent Antibody Test (“POD” Test) Sensitivity and specificity of 98.7% and 98.9% 5. Dimov N, et al. Cancer. 2010;116:369-376.

31. Microgranular variant Hypergranular variant 20% of cases majority of cases (80%) Incidence Leukocytosis Leukopenia Clinical Presentation reniform , bilobed nuclei with scant to inconspicuous granules packed with granules, numerous Auer rods in single cell Pathology CD34, is often positive CD13+, CD33+, MPO+, CD34–, HLA-DR– Flowcytometry

32. Treatment

33. APL Leukemic Infiltration Coagulopathy

34. Treatment Counseling As APML is a hematologic emergency, so immediate treatment starting with ATRA when APML is suspected regardless of cytogenetic/molecular study. Supportive treatment Hydration and prevention of TLS Blood product support Oral care, Anal care, Antibiotics etc.

35. - It occurs in 70% to 90% of cases. - It occurs due to release of several procoagulants , mainly tissue factor (TF), and cancer procoagulant (CP). - DIC complicated by APML is characterized by exaggerated fibrinolysis and life-threatening hemorrhage. DIC in APML

36. ---Platelet transfusion to maintain >50,000/ cumm . ---FFP transfusion- T o correct PT, APTT. ---Fibrinogen must be kept over 150 mg/ dL . Note: Treatment - Heparin is of no documented value. - packed RBCs transfusion may worsen the condition . - Avoid invasive procedures if possible (LP and central line placement).

37. Specific treatment NCRI-CSG APML (in children and adolescents) Management guidelines NCCN guidelines for patients (APML in children and adolescents) 2020

38. - Using “ Sanz ” criteria ( Sanz score). - Depending on WBC & Platelets count at presentation. 3-yr relapse-free survival Platelet count (X 10 9 /L) WBC count (X 10 9 /L) Risk Group 98% >40 ≤ 10 Low Risk 89% ≤ 40 ≤ 10 Intermediate 70% <40 >10 High Risk Risk stratification

39. . WBC Count Risk Group (10  X 10 9 /L or less ) Standard /Low risk ( > 10  X 10 9 /L ) High risk Risk stratification

40. Induction Drugs Dose Duration ATRA 25mg/m2/day BD 30 days Idarubicin 12 mg/m2/day, IV, OD Day-3, 5, 7 Consolidation I Drugs Dose Duration ATRA 25mg/m2/day BD 14 days Cytarabine 1 g/m2, IV, BD Day-2, 3, 4 Mitoxantrone 10mg/m2/day Day-4, 5 IT cytarabine Day-0

41. Consolidation II Drugs Dose Duration ATRA 25mg/m2/day BD 14 days Idarubicin 5 m g/m2/day, IV, 0D Day-1 3 5 IT cytarabine Day-0 Consolidation III Drugs Dose Duration ATRA 25mg/m2/day BD 14 days Cytarabine 1 g/m2, IV, BD Day-1, 2, 3 Idarubicin 10mg/m2/day Day-4 IT cytarabine Day-0

42. Maintenance Drugs Dose Duration ATRA 25mg/m2/day BD First 14 days in every 12 wks upto 24 months 6 MP 50 m g/m2, , 0D 24 months MTX 25mg/m2/once weekly Upto 24 months IT cytarabine Day-1 only

43. Relapse

44. Relapse

45. Prognostic factor High WBC count at presentation (>10  X 10 9 /L ) Expression in APL blasts of the stem/progenitor cell antigen CD34, the neural adhesion molecule (CD56) and T cell antigen CD2 Short PML/RARA isoform and FLT3-internal tandem duplication (ITD) mutations. Ref: Ann Hematol. 2016 Apr;95(5):673-80

46. Types of complete response (remission) When there are no signs or symptoms of  cancer , it is called Complete Remission . Induction often causes a large drop in  the number of blasts. This is called a  Morphologic Complete Response.  When the translocation of chromosomes 15 & 17 or t(15;17 ) is no longer found,  it is called Cytogenetic Complete Response .  

47. A Molecular Response is defined as the  absence of the PML-RARA gene. This  means the PML-RARA gene is not found. A molecular complete response will likely follow a cytogenetic response . Often, more treatment is needed to  achieve molecular response . Types of complete response (remission)

48. Follow up plan Clinical : Fever, bleeding manifestation, complications related to ATRA – Wt gain, respiratory distress. Laboratory: 1. CBC 2. Coagulation profile: -PT with INR, APTT -Fibrinogen level 3. Renal function 4. Liver function

49. -- Document complete molecular remission by PCR after consolidation. -- After completing maintenance therapy, patient will enter in a monitoring phase. -- Monitoring is a prolonged period of testing to see whether APML returns or not. -- Bone marrow or blood sample may be used. --No drug therapy during this time. Monitoring in APL

50. -- Monitor PCR every 3 months up to 2 years. -- If PCR – ve , continue maintenance. -- If PCR + ve , repeat within 4 weeks to confirm. -- If PCR still + ve , proceed to treatment of relapse. Monitoring in APL

51. ATRA APML is unique among leukemias due to its sensitivity to all- trans retinoic acid ( ATRA; tretinoin ), the acid form of vitamin A. ATRA is fast acting and it can improve coagulopathy within 48 hours to 5 days. Treatment with ATRA dissociates the repressor complex from RAR and allows DNA transcription and differentiation of the immature leukemic promyelocytes into mature granulocytes.

52. ATRA induces terminal differentiation

53. . Effect of ATRA on Coagulation pathway

54. Side effects of ATRA

55. Side effects of ATRA

56. Differentiation syndrome The differentiation syndrome (previously called "retinoic acid syndrome") is a potentially fatal complication of induction chemotherapy in patients with acute promyelocytic leukemia (APL). It usually occur in the first 1-2 weeks of treatment. It is characterized by peripheral edema, Weight gain hypoxemia, respiratory distress hypotension, Unexplained fever renal and hepatic dysfunction, Rash and serositis resulting in pleural and pericardial effusion.

57. Differentiation syndrome

58. . It is a cytokine release syndrome, sometimes called "cytokine storm," and all of the pathophysiologic consequences result from the release of inflammatory cytokines from malignant promyelocytes which causes increased vascular permeability, probably independent of their differentiation to segmented neutrophils and hyperleukocytosis . The syndrome is seen in patients treated with Arsenic Trioxide as well as in those treated with ATRA . Although these symptoms most often correlate with leukocytosis (WBC > 10,000/ μL ) , many patients develop symptoms with WBC counts between 5,000/ μL - 10,000/ μL Differentiation syndrome

59. Treatment Temporary discontinuation of ATRA. Prompt initiation of Dexamethasone 10mg/m2 -12 hourly until disappearance of signs and symptoms (minimum 3 days ). Initiation of conventional Ara -C/ daunorubicin chemotherapy to control leukocytosis . Frusemide . Continue treatment with ATRA after controlling the situation . Prophylaxis: Steroid commonly recommended, in patients with elevated WBC.

60. Arsenic Tri Oxide (ATO) Despite its historical reputation as a toxin and poison, ATO has been used in a variety of diseases for many countries. ATO has now emerged as the treatment of choice for patients with refractory/relapsed APML as well as newly diagnosed APML. Advantage: - Early remission. - Can cross blood brain barrier, so effective in APML with CNS involvement. -Less myelosuppresion. -No need of further Anthracycline exposure.

61. Disadvantages Limited data on pediatric use. Optimal dosing schedule is not known. ECG alterations (prolongations of the QT interval). Electrolyte shifts (commonly involve K +, Mg). Other frequently occurring, but not life-threatening adverse effects are nausea, vomiting, exanthema, fatigue, fever, neuropathy, functional liver disorders and increase of transaminase activities and diarrhea . Bleeding does not improve as rapidly as ATRA, so the chance of early mortality persists.

62. Comparison S/E of ATO

63. Newer targeted therapy Gemtuzumab ozogamicin - used in the western countries, in combination with ATRA plus ATO in high risk APML patients as well as relapsed patient proves safe and effective. ATRA - ATO with minimal chemotherapy shows better success rate to standard ATRA plus anthracycline . Tamibarotene (AM-80 )- Tami-ATO combination shows similar efficacy & less toxic than ATRA- ATO combo now used in Japan. .

64. Treatment outcome Pre ATRA era - 6-MP alone/in combination with steroids: CR ( 5-14% ) - Anthracyclines with daunorubicin given as monotherapy : complete remission appoximately (CR) 30%

65. . ATRA WITH ANTHRACYCLINE Title: Risk-adapted treatment of acute promyelocytic leukemia: results from International Consortium for Childhood APL Source : RESULT % CR 94.6% 5yrs EFS 95% in SR 5yrs EFS 84.3% in HR

66. . ATRA WITH ATO Title Arsenic trioxide and all-trans retinoic acid (ATRA) treatment for acute promyelocytic leukemia in all risk groups: study protocol for a randomized controlled trial. Source: RESULT % CR 96% 5yrs DFS 94% 5yrs EFS 85%

67. . ATRA WITH ATO AND GEMTUZUMAB Title Long-term outcome of acute promyelocytic leukemia treated with all-trans-retinoic acid, arsenic trioxide, and gemtuzumab . Source: RESULT % CR 97% 5yrs DFS 95% 5yrs EFS 85%

68. Take home message It is one of the fatal but most curable myeloid malignancy. Acute life threatening hemorrhage with leukemia like feature regrade high index of suspicion. Clinical suspicion and immediate referral to a centre of expertise may save lives . Several established treatment protocols offer excellent outcomes . Important not to “ mix and match ” induction from one trial with consolidation from another. Good supportive care during induction is essential to control DIC and ATRA syndrome .

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