internal medicine

1. Chronic Myeloid Leukemia
Dr K R Sharma

2.  Introduction of CML
 Molecular genetics of CML
 Clinical manifestations and diagnosis of CML
 Overview of the treatment of CML
 Initial treatment of chronic myeloid leukemia in
chronic phase

3.  Explain how to define and identify a relapse
 Treatment of CML in chronic phase after failure of
initial therapy
 Clinical use of tyrosine kinase inhibitors for
chronic myeloid leukemia
 Treatment of CML in accelerated phase and blast
crisis
 Prognosis

4.  CML is a clonal myeloproliferative neoplasm
 Dysregulated production and uncontrolled proliferation of
mature and maturing granulocyte with fairly normal
differentiation
 Fusion of 2 genes: BCR- ((breakpoint cluster region) on
chromosome 22) and ABL1( Ableson leukemia virus ) (on
chromosome 9), resulting in BCR-ABL1 fusion gene
 Final result: Abnormal chromosome 22 called Philadelphia
(Ph) chromosome
 Final product: BCR-ABL1 fusion protein, a dysregulated
tyrosine kinase

5.  Uncontrolled production of mature and maturing
granulocytes
 Predominantly neutrophils, but also basophils and
eosinophils
 Triphasic or biphasic clinical course
 Chronic phase, accelerated phase, blast crisis

6.  Annual incidence: 1 to 2 cases per 100,000
 15% – 20% of all adult leukemias
 Incidence increases significantly with age
– Median age: ~ 55 years
– Prevalence increasing due to current therapy
– Most patients present in CP, 85%
• Majority of CML-related deaths due to progression to AP/BC
– 50% of CML patients are asymptomatic at diagnosis
 Risk factors
– Exposure to ionizing radiation, the only known

7.  The Philadelphia chromosome was originally detected by
workers in Philadelphia.
 The first genetic abnormality to be associated with a human
cancer.
 The result of a balanced translocation between chromosomes 9
and 22.
 Derivative chromosome 22 is significantly smaller
 Therefore, the Ph chromosome is acquired and NOT inherited
through the germline.
 Ph chromosome is found on myeloid, monocytic, erythroid,
megakaryocytic, B-cells and sometimes T-cell proof that CML
derived from pluripotent stem cell

8. BCR
ABL
BCR
ABLBCR{q11
Ph
9q+
22
9
{q34 ABL

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
 The development of chronic phase CML appears to be a direct result of the
BCR-ABL1 activity, which promotes its development by allowing:
I. Uncontrolled proliferation of transformed cells
II. Discordant maturation
III. Escape from apoptosis
IV. Altered interaction with the cellular Matrix
 The progression of CML from chronic phase to accelerated face or blast
crisis is a complex, multistep process (may be related to GMP).
 Also, it appears to involve the constitutive expression of the BCR-ABL1
tyrosine kinase.

12.  Asymptomatic in 20-50% of patients
 Fatigue 34%, weight loss 20%, excessive sweating
15%, abdominal fullness 15%, bleeding episodes 21%
(platelet dysfunction).
 Abdominal pain in the LUQ (enlarged spleen)
 Tenderness over the lower sternum.
 Acute gouty arthritis
 Findings: Splenomegaly, anemia, WBC > 100,000,
platelet count > 600,000

13.  Leukocytosis (median of 100,000)
 Differentiation shows virtually all cells of
neutrophilic series
 Blasts < 2%
 Myelocytes more than metamyelocytes (a classic
finding in CML)
 Basophilia in 90% of cases
 Thrombocytosis. If low platelets – consider an other

16.  Granulocytic maturation pattern same as in the
peripheral blood
 Increased reticulin fibrosis and vascularity
 Erythroid islands are reduced in number and size
 Dwarf megakaryocytes
 Pseudo-Gaucher’s cells and Sea Blue histiocytes
(markers of increased cell turnover)
 Iron-laden macrophages are reduced or absent

17. A. Laboratory studies
17Diagnosis
Bone marrow
Hypercellular
Replacement of fat
Granulopoiesis
Megakaryocytopoiesis
Erythropoiesis

22. 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
22Diagnosis

23.  Typical findings in the blood and bone marrow
 Requires the detection of the Ph chromosomal or its
product, the BCR-ABL1 fusion mRNA and the BCR-ABL1
protein.
 Conventional cytogenetic analysis (karyotyping) – The first
method
 Florence and in situ hybridization (FISH) analysis
 RT-PCR (The BEST)

24. 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
24Diagnosis

25. Molecular Probes
i. FISH (Fluorescence In Situ Hybridization)
 Detect the BCR-ABL fusion gene on chromosome 22
 Qualitative
Diagnosis
25

26. Molecular Probes
ii. RT-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
26

27.  CML has 3 phases
27
Stage of disease at the time of diagnosis is the strongest single
predictor of outcome
I. Chronic Phase
• Most patients are asymptomatic
• Incidental leukocytosis/splenomegaly
• Bleeding and infectious complications are uncommon in the chronic
phase
• Most CML patients are diagnosed in the chronic phase

28.  10-19% blasts in the peripheral blood or bone marrow
 Peripheral blood basophils ≥20%
 Platelets < 100,000/microL, unrelated to therapy
 Platelets > 1,000,000/microL, unresponsive to
therapy
 Progressive splenomegaly and increasing WBC,
unresponsive to therapy
 Cytogenic evolution

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)
 Blast crisis is generally refractory to treatment,
occurs approximately 3-5 years after the diagnosis
of CML and 18 months after the onset of accelerated
face Course of the disease
29

31.  Relieve symptoms of hyperleukocytosis, splenomegaly and
thrombocytosis.
 Hydration
 Chemotherapy (Busulfan, hydroxyurea)
 Control and prolonging the chronic phase (non-curative)
 Tyrosine kinase inhibitors
 Alpha-interferon + chemotherapy
 Chemotherapy (hydroxyurea)
 Potential cure with allogeneic hematopoietic stem cell
transplantation

33. 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
33

34. 2. Tyrosine Kinase inhibitor therapy
Treatment
34
First generation Second generation
Imatinib
Dasatinib
Nilotinib
Bosutinib
Ponatinib
Bafetinib

35.  They block the initiation of bcr-abl pathway
 Many TKIs also affect other signaling pathways
 Dasatinib and Bosutinib inhibit both Bcr-Abl and
Src kinases.
 Nilotinib inhibits Bcr-Abl, c-kit and platelet
derived growth factor receptor (PDGFR)
 These differences in targeted pathways may be
responsible for their varied clinical effects in
tumors

36.  Competitively inhibits the inactive configuration
of the Bcr-Abl protein tyrosine kinase
 Blocking the ATP binding site and thereby
preventing a conformational switch to the active
form
 Inhibits cellular proliferation and tumor
formation
 Produces 95% decrease in CML colony growth
 Inhibits platelet-derived growth factor and c-kit

37. 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
37

38. 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
38

39. Imatinib Mesylate
Treatment
39

40. Imatinib Mesylate
Treatment
40
90-96%

41. Imatinib Mesylate
Treatment
41
~63%

42. Imatinib Mesylate
Treatment
42
National Comprehensive Cancer Network

43. 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
43

44. 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
44

45. 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
45

46. 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
 IFNα was combined with Cytarabine
 Some patients intolerant to a Imatinib may be
treated successfully with INFα
Treatment
46

47. 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
47

48. 4. Chemotherapeutic Agents and other
modalities
iii. Splenectomy*
 Delay the onset of the accelerated phase
 Enhance sensitivity to chemotherapy
 Prolong survival of patients
iv. Radiotherapy
 Splenic irradiation - extreme splenomegaly with splenic pain,
perisplenitis
 may be useful for extramedullary tumors (bone/soft tissue)
Treatment
48

49. 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
49

50. 5. Allogeneic Stem Cell Transplantation
 Allogeneic HSCT - complicated by mortality owing to
the procedure
(1) The patient
(2) The preparative regimen (myeloablative or reduced-
intensity)
(3) Graft versus Host Disease
(4) Post-transplantation treatment
Treatment
50

51. 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
51
Blast crisis

52. 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
52

53. 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
53

54.  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
54

55.  Increase the dose of imitinib
 A trial of another TKI.
 Dasatinib preferred in patients with pancreatitis, elevated
bilirubin or hyperglycemia
 Dasatinib crosses the blood brain barrier and would
therefore be preferred in patients with CNS involvement
 Nilotinib might be chosen for patients with a history of
pleural or pericardial effusion or disease
No randomized trials have directly compared the
efficacy of second-generation TKIs in patients
with chronic phase CML who experience failure
of an initial TKIs

56.  Patients who are ineligible for HCT but have either a
contraindication to a second-generation TKI or have failed
to respond to treatment with available TKI
 Interferon alfa plus cytarabine
 Hydroxyurea
 Busulfan
 Omacetaxine mepesuccinate – SQ Injection
 Approved by the FDA for patients resistant or intolerant to
2 or more TKIs
 Hematopoietic cell transplant – the only cure
 Clinical trials

57.  Primary resistance – patient fails to
achieve a desired response to initial
treatment
 Secondary resistance – patient with an
initial response to a TKI ultimately relapses
Resistance to Imatinib occurs
predominantly during advanced phase
CML

58.  They are metabolized by the CYP3A4 system
– can inhibit other cytochrome P450
pathways
 Low TKIs levels –rifampin, carbamazepine,
phenobarbital and phenytoin
 High TKIs levels – diltiazem, verapamil,
itraconazole, ketoconazole, clarithromycin,
erythromycin and grapefruit juice

59.  Imatinib - Bone marrow suppression; fluid
retention/edema; gastrointestinal effects; heart failure;
hepatotoxicity
 Dasatinib - Bone marrow suppression; pleural/pericardial
effusions; pulmonary arterial hypertension; QT prolongation;
aspirin like effect
 Bosutinib - Bone marrow suppression; fluid
retention/edema; gastrointestinal effects

60.  Nilotinib - Bone marrow suppression;
atherosclerosis-related events; electrolyte imbalance;
hepatotoxicity
 Black box: QT prolongation (screening required)
 Ponatinib - Bone marrow suppression; fluid
retention/edema; gastrointestinal effects; heart
failure; hypertension; pancreatitis; aspirin-like effect
 Black box: Arterial thrombosis; hepatic toxicity