Acute Promyelocytic Leukaemia (APML)

1. Presenters:
DR. RENESHA ISLAM
DR. MDIMRANHABIB
YEAR-3 RESIDENT (PHASE-B)
PAEDIATRIC HAEMATOLOGY & ONCOLOGY
BANGABANDHU SHEIKH MUJIB MEDICAL
UNIVERSITY
(BSMMU)
WELCOME
TO
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.

7. 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.

8. .
 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.

9.  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%.

10. 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 0
Outcome Alive and on treatment 9
Death (ICH-2, stroke-1) 5
Loss of contact 4

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

12. .
 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.
.

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

14. Molecular pathogenesis

15. .
 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.

17. 18/3/2014 17 APL

18. .

19. APML t(15,17)

20. 18/3/2014 20 APL

21. .

22. 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.

23. .
 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.

25. 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.

26. 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.

27. Diagnosis of APL

28. Diagnosis of APL
Clinical
Morphological
Immunophenotyping
Molecular genetics
Cytogenetics

29. .

30. 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”.

31.  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).
,

32. 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

33. 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.

34. 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

35. Treatment

36. APL
Leukemic
Infiltration
Coagulopathy

37. 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
o Hydration and prevention of TLS
o Blood product support
o Oral care, Anal care, Antibiotics etc.

38. - 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

39. ---Platelet transfusion to maintain >50,000/cumm.
---FFP transfusion- To 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).

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

41. - Using “Sanz” criteria (Sanz score).
- Depending on WBC & Platelets count at presentation.
3-yr relapse-
free survival
Platelet count
(X 109/L)
WBC count
(X 109/L)
Risk Group
98%
>40
≤ 10
Low Risk
89%
≤40
≤ 10
Intermediate
70%
<40
>10
High Risk
Risk stratification

42. .
WBC Count Risk Group
(10 X 109/L or less ) Standard /Low risk
(>10 X 109/L )
High risk
Risk stratification

43. Consolidation II
MRD + MRD -
Consolidation I
MRD
Induction
MRD
Standard risk
MRD +
Consolidation III
MRD
MRD -
Maintenance(2 years)
Stop
MRD +
Refractory/
Relapse
protocol
MRD -
Maintenance(2
years)
Stop

44. Consolidation II
MRD
Consolidation I
MRD
Induction
MRD
High risk
MRD +
Refractory/
Relapse
protocol
MRD -
Maintenance
(2 years)
Stop
Consolidation III
MRD

45. 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

46. Consolidation II
Drugs Dose Duration
ATRA 25mg/m2/day BD 14 days
Idarubicin 5 mg/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

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

51. Relapse

52. Relapse

53. Prognostic factor
 High WBC count at presentation (>10 X 109/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

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

55. 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)

56. 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

57. -- 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

58. -- 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

59. 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.

60. ATRA induces terminal
differentiation

61. .
Effect of ATRA on Coagulation pathway

62. Side effects of ATRA

63. Side effects of ATRA

65. 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.

66. Differentiation syndrome

67. .
• 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

68. 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.

69. 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.

70. 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.

71. Comparison S/E of ATO

73. 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. .

74. 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%

75. .
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

76. .
 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%

77. .
 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%

78. 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.