CHRONIC
MYELOGENOUS
LEUKEMIA

Definition, History & Epidemiology
Etiology and Pathogenesis
Clinical Features
Diagnosis
Course and special clinical situations
Differential Diagnosis
Therapy
2

The 2008 World Health Organization Classification
System for Myeloproliferative Neoplasms

DEFINITION
• Chronic myelogenous leukemia (CML) - pluripotential
stem cell disease characterized by
• Anemia
• Extreme blood granulocytosis and granulocytic
immaturity
• Basophilia
• Thrombocytosis
• Splenomegaly
• Characteristic genetic change - Reciprocal
translocation between chromosomes 9 and 22
(Philadelphia (Ph) chromosome)
4

HISTORY
• In 1845, Bennett in Scotland and Virchow in Germany
described splenic enlargement, severe anemia, and
leukocytosis at autopsy
• Virchow proposed the term leukämie
• In 1878, Neumann proposed – marrow origin for
leukemia – myelogene (myelogenus)
• Nowell and Hungerford in 1960 identified the culprit
gene at the Perelman School of Medicine, Philadelphia
• Dr. Rowley identified the BCR-ABL translocation
• 1998 – Discovery of targeted TKI therapy
5

EPIDEMIOLOGY
• CML - 15 %of all cases of Leukemia
• US Incidence ~ 2 per lakh persons for men and 1.1 per
lakh persons for women
• Sparse Indian data - 0.8–2.2/lakh in men and 0.6–
1.6/lakh in women
• 50-70% of leukemias in India
• Male predominance (1.4:1)
• Average age at presentation – 50 yrs
• Incidence is least in Swedes
6

EPIDEMIOLOGY
7

ETIOPATHOGENESIS
1. Environmental Leukemogens
• Very high doses of ionizing radiation*
• Chemical leukemogens - benzene and alkylating agents
– are not causative – increased incidence of AML
• No concordance of the disease between identical twins
• Several large studies – no links with smoking/diet/lifestyle
8

Etiopathogenesis
9
2. The stem cell

2. The stem cell
Etiopathogenesis
10
CML Stem Cell

2. The stem cell
• Acquisition of the BCR-ABL fusion gene in a single
multipotential hematopoietic cell  CML stem cell
• Majority of these cells would be in G0 phase of the cell
cycle
• These BCR-ABL stem cells favor differentiation over self-
renewal
• Ph chromosome is found on myeloid, monocytic,
erythroid, megakaryocytic, B-cells and sometimes T-cell
proof that CML derived from pluripotent stem cell
Etiopathogenesis
11

2. The stem cell
• The CML stem cells
have no regulation of
proliferation
• Mediated by IL3 –
GCSF autocrine loop
• Immature
granulocytes >>
mature granulocytes
Etiopathogenesis
12

3. BCR-ABL protein (Tyrosine Kinase)
• BCR (breakpoint cluster region) gene on chromosome
22 fused to the ABL (Ableson leukemia virus) gene on
chromosome 9
• The fusion protein derived from the BCR-ABL gene is a
tyrosine kinase enzyme
• This particular protein is seen in small amounts normally*
• The ABL gene  regulated tyrosine kinase
• BCR-ABL  unregulated tyrosine kinase
Etiopathogenesis
13

3. BCR-ABL (Tyrosine Kinase)
Etiopathogenesis
14
Altered
adhesion
•No adhesion to
marrow stroma
•Reduced
regulation by
marrow factors
Mitogenic
activation
•Activation of
various
pathways 
proliferation
Inhibition of
apoptosis
•Upregulation of
Bcl-2
•Uninhibited
proliferation

CLINICAL FEATURES
A. Symptoms
• At diagnosis – 70% symptomatic
• Easy fatigability
• Loss of sense of well-being
• Decreased tolerance to exertion
• Anorexia
• Abdominal discomfort
• Early satiety *
• Weight loss
• Excessive sweating
15

A. Symptoms
• Uncommon symptoms
• Night sweats
• Heat intolerance
• Gouty arthitis
• Left upper-quadrant and left shoulder pain*
• Urticaria
• Hyperleukocytic Syndrome —dyspnea, tachypnea,
hypoxia, lethargy, slurred speech
Clinical features
16
Mimics thyrotoxicosis

Clinical features
17
Acute febrile neutrophilic
dermatosis (Sweet syndrome)
A. Symptoms

B. Signs
• Pallor
• Splenomegaly
• Sternal tenderness
• Rarely hepatomegaly,
lymphadenopathy – Poor
prognostic indicators
Clinical features
18

DIAGNOSIS
A. Laboratory studies
Blood counts and blood smear
• Hemoglobin concentration is decreased
• Nucleated red cells in blood film
• The leukocyte count above 25,000/μl (even > 1,00,000/μl),
• Hypersegmented neutrophils
• The basophil and eosinophil counts are increased
(Absolute)
• The platelet count is normal or increased
• Blast cells ~ 3 % (<10% in the chronic phase)
19

A. Laboratory studies
Diagnosis
20
Peripheral smear

A. Laboratory studies
Diagnosis
21
Bone marrow
Hypercellular
Replacement of fat
Granulopoiesis
Megakaryocytopoiesis
Erythropoiesis

A. Laboratory studies
Bone Marrow studies
• Mitotic figures are increased
• Macrophages that mimic
Gaucher cells *
• Macrophages - engorged
with lipids - yield ceroid
pigment - imparting a granular
and bluish cast - sea-blue
histiocytes
• Increased reticulin fibrosis
(Collagen type III) *
• Angiogenesis
Diagnosis
22

A. Laboratory studies
Other lab features :
• Neutrophil Alkaline Phosphatase reduced
• Serum B12 and transcobalamin increased (>10 ULN)
• Serum uric acid increased
• Lactate dehydrogenase increased
• Mean histamine levels increased
Diagnosis
23

B. Cytogenetics
• Study of the number and structure of chromosomes
• Samples from bone marrow myeloid cells
• The presence of the Philadelphia chromosome –
shortened chromosome 22*
• Cytogenetics cannot identify complex translocations
Diagnosis
24

B. Cytogenetics
Diagnosis
25
90%

C. Molecular Probes
i. FISH (Fluorescence In Situ Hybridization)
• Detect the BCR-ABL fusion gene on chromosome 22
• Qualitative
Diagnosis
26

C. Molecular Probes
ii. PCR (Polymerase Chain Reaction)
• Most sensitive test to identify and measure the BCR-ABL
gene (Quantitative)
• Can be performed on blood/marrow cells
• Amplifies the BCR-ABL derived abnormal mRNA
• One abnormal cell in one million cells can be detected
Diagnosis
27

COURSE OF THE DISEASE
• CML has 3 phases
28
I. Chronic Phase
• Most patients are asymptomatic
• Incidental leukocytosis/splenomegaly
• Bleeding and infectious complications are uncommon
in the chronic phase

II. Accelerated phase
defined by
• 10%–19% blasts in blood or bone marrow
• >20% basophils in blood or bone marrow
• Thrombocytosis, thrombocytopenia unrelated to
therapy (<1 lakh>)
• New clonal chromosome abnormalities
• Anemia progresses and cause fatigue, loss of sense of
well-being
• Splenomegaly
• Ranges from 4-5 years before progressing
Course of the disease
29

III. Blast Crisis
defined by
• ≥20% blasts in blood or bone marrow
• Extramedullary blastic infiltration (Chloroma)
• Resembles acute leukemia
• 2/3 transform to myeloid blastic phase and 1/3 to lymphoid
blastic phase
• Infection and bleeding common
• Abdominal pain, bone pain
• Survival is 6-12 months (worse for myeloid phenotype)
Course of the disease
30

Special Clinical situations
Neutrophilic CML
• A rare variant of BCR-ABL–positive CML with elevated
white cell count principally of mature neutrophils
• WBC count lower than that of classic CML
• Basophilia, myeloid immaturity in the blood, prominent
splenomegaly, or low leukocyte alkaline phosphatase
scores – are all absent!
• Larger fusion protein than in classic CML
• Usually has an indolent course
• Now classified separately
Course of the disease
31

Special Clinical situations
Hyperleukocytosis (15% of cases)
• Intravascular flow-impeding effects of white cell counts
greater than 3,00,000/µL (upto 8 lakh)
• Impaired circulation of the lung, central nervous system,
special sensory organs, and penis
• resulting in some combination of
• Tachypnea, dyspnea, cyanosis,
• Dizziness, slurred speech, delirium, stupor,
• Visual blurring, diplopia, retinal vein distention, retinal
hemorrhages, papilledema,
• Tinnitus, impaired hearing,
• And priapism
Course of the disease
32

Special Clinical situations
Concurrence of Lymphoid Malignancies
1. CML years after irradiation of non-Hodgkin or Hodgkin
lymphoma
2. Accelerated phase  dedifferentiation of the CML
clone  acute lymphoblastic transformation
3. Plasmacytic malignancies – positive association
4. Patients may present with Ph+ ALL, after
chemotherapy-induced remission, develop the
features of typical CML
Course of the disease
33

DIFFERENTIAL DIAGNOSIS
• Polycythemia vera
• Essential thrombocythemia
• Primary myelofibrosis
• Leukemoid reactions
34

TREATMENT
1. Initial Cytoreduction Therapy
2. Tyrosine Kinase Inhibitor Therapy
3. Interferon therapy
4. Chemotherapy
5. Allogeneic Stem Cell Transplantation
6. Treatment of accelerated/blast phases
7. Treatment of CML in pregnancy
8. Treatment cessation
35

1. Initial therapy
• Allopurinol 300 mg/day orally with adequate hydration 
Rasburicase 0.2 mg/kg i.v (one doses) for Hyperuricemia*
• Leukapheresis – helps reduce leucocyte burden, only in
conjunction with definitive therapy
• Hydroxyurea - Reversible suppression of hematopoiesis
1 to 6 g/day orally (titre based on counts)
• Anagrelide – to reduce the platelet burden
Treatment
36

2. Tyrosine Kinase inhibitor therapy
Treatment
37
First generation Second generation
Imatinib
Dasatinib
Nilotinib
Bosutinib
Ponatinib
Bafetinib

2. Tyrosine Kinase inhibitor therapy
Imatinib Mesylate
• Approved for use in Ph+ CML in 2001
• Preliminary studies showed a remarkable cytogenic
remission
• Hematological remission was seen in 95%
• Now the treatment of choice for CML
Treatment
38

2. Tyrosine Kinase inhibitor therapy
Imatinib Mesylate
Treatment
39

2. Tyrosine Kinase inhibitor therapy
Imatinib Mesylate
• Dosage –400 mg/day orally  400 mg BD
• Well tolerated
• Myelosuppression is common in CML patients
• Elevated hepatic transaminases (Acute liver failure
described)
• Periorbital edema
• Cutaneous reactions
• Osteoporosis
Treatment
40

2. Tyrosine Kinase inhibitor therapy
Imatinib Mesylate
Treatment
41

2. Tyrosine Kinase inhibitor therapy
Imatinib Mesylate
Treatment
42
90-96%

2. Tyrosine Kinase inhibitor therapy
Imatinib Mesylate
Treatment
43
~63%

2. Tyrosine Kinase inhibitor therapy
Imatinib Mesylate
Treatment
44
National Comprehensive Cancer Network

2. Tyrosine Kinase inhibitor therapy
Imatinib Mesylate
Treatment
45
European Leukemia Net

2. Tyrosine Kinase inhibitor therapy
Imatinib Mesylate
Four mechanisms of resistance
(1) Gene amplification
(2) Mutations at the kinase site
(3) Enhanced expression of multidrug exporter proteins
(4) Alternative signaling pathways compensating
imatinib-sensitive mechanisms.
Treatment
46

2. Tyrosine Kinase inhibitor therapy
2nd Generation TKI
1. Dasatinib
• Used in imatinib resistance or intolerance
• 325-fold more potent than imatinib
• 100 mg/day, administered in chronic phase CML
• Unlike imatinib, dasatinib penetrates the blood–brain
barrier
• Cytopenia, followed by fluid retention, diarrhea, and skin
rash
Treatment
47

2. Tyrosine Kinase inhibitor therapy
2nd Generation TKI
2. Nilotinib
• Used in imatinib resistance or intolerance
• 30 times more potent than imatinib
• ATP-competitive inhibitor of BCR-ABL
• 400 mg every 12 hours
• Neutropenia, hyperbilirubinemia, hypophosphatemia, QT
interval prolongation
• Imatinib and nilotinib in combination may have additive
or synergistic effects
Treatment
48

3. Interferon α
• IFNα was the initial therapy before TKI therapy
• Complete cytogenetic response – uncommon (13%)
• 50% responders – long term survival
• 3-5 million units/m2 five times per week
• Neurotoxicity, thrombocytopenia, fatigue, and liver
dysfunction  dose limiting effects
• Single dose of 450 µg pegylated IFNα – comparable
• IFNα was combined with Cytarabine
• Some patients intolerant to a Imatinib may be treated
successfully with INFα
Treatment
49

4. Chemotherapeutic Agents and other modalities
i. Cytarabine
• IFNα combined with cytarabine (20 mg/m2/day -10
days per month  better than IFN alone
• Replaced by TKI
ii. Busulfan
• Once the mainstay of treatment – now almost never
used
• Use limited to the preparative regimen for allografting
or autografting
Treatment
50

4. Chemotherapeutic Agents and other modalities
iii. Splenectomy*
• Delay the onset of the accelerated phase
• Enhance sensitivity to chemotherapy
• Prolong survival of patients
• But, does not prolong the chronic phase
iv. Radiotherapy
• Splenic irradiation - extreme splenomegaly with
splenic pain, perisplenitis
• may be useful for extramedullary tumors (bone/soft
tissue)
Treatment
51

4. Chemotherapeutic Agents and other modalities
v. Omacetaxine (formerly Homoharringtonine)
• Protein translation inhibitor
• Still in Phase 2 trials
• Showed promise in TKI intolerant/resistant cases
• 18% major cytogenetic response in TKI failed cases
vi. Experimental
• Lonafarnib and tipifarnib
• Berbamine
• Adaphostin
• Third-generation TKIs
Treatment
52

5. Allogeneic Stem Cell Transplantation
• Allogeneic HSCT - complicated by mortality owing to the
procedure
(1) The patient
(2) The type of donor
(3) The preparative regimen (myeloablative or reduced-
intensity)
(4) Graft versus Host Disease
(5) Post-transplantation treatment
Treatment
53

6. Treatment of accelerated/blast phases
• Goal  achieve remission
• Else aim to reduce to chronic phase
• TKI – bridging therapy to permit allogenic SCT
• Dasatinib and nilotinib achieve better molecular
remission in accelerated phase
• Imatinib+mitoxantrone+etoposide
• Imatinib+cytarabine
• Ultimately – Stem cell transplant
Treatment
54
Blast crisis

7. Treatment of CML in pregnancy
• Untreated CML  placental insufficiency (leukostasis)
• Risk of teratogenicity with Imatinib
• IFN is safe – can be used
• Leukapheresis – 1st trimester
• Hydroxyurea – 2nd and 3rd trimester
• Restart TKI therapy soon after delivery
Treatment
55

8. Treatment cessation
• Despite achieving deep and lasting remissions
• CML is not curable
• Patients with remissions still have residual CML cells
(PCR)
• Available evidence suggests that people who receive
TKIs may remain in remission for very long periods
• Research still underway
Treatment
56

57
Treatment

CONCLUSION
• Imatinib has revolutionized the management of CML
• Long term survival is a reality now
• TKI therapy is still not curative
• 3rd generation TKI and newer drugs in the pipeline show
some promise at achieving a possible cure
58