LEUKEMIA By,

Chinmayi Upadhyaya

1st M.Pharm (Pharmacology)

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OBJECTIVES:• To define Leukemia.

• To understand the Etiology.

• To classify Leukemia.

• To understand the Pathophysiology .

• To be able to list the Symptoms.

• To understand the Pharmacotherapy.

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WHAT IS LEUKEMIA? Is a group of cancers that usually begins in

the Bone marrow and results in high number of abnormal White Blood cells.

• No single causative agent • Most from a combination of factors

– Genetic, environmental and infections.

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3.Infection: i. Human T- cell Leukemia viruse type 1(HTLV-1).ii. Human T- cell Leukemia viruse type 11 (HTLV-11).

1. Genetic factors:2. Environmental factors:

• Down’s syndrome.• Bloom’s syndrome.• Klinefelter’s syndrome.• Wiskott- Aldrich’s syndrome.• Fanconi’s anaemia.• Ataxia telangiectasia.

• Ionising radiation.• Chemical carcinogens.• Certain drugs.

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Classification of leukemias:

Based on cell types predominately involved andon natural history of the disease:

– Acute lymphoblastic leukemia (ALL).– Acute myelogenous leukemia (AML).– Chronic myelogenous leukemia (CML).– Chronic lymphocytic leukemia (CLL).

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Myeloid vs. Lymphoid:• Any disease that arises from the myeloid elements (white blood cells) is a myeloid disease. ….. AML, CML • Any disease that arises from the lymphoid elements (T cell and B cell) is a lymphoid disease. ….. ALL, CLL

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1.1. Acute leukemiasAcute leukemias::Immature cells (or “Blasts") proliferate rapidly and begin to accumulate in various organs and tissues.

• Sudden onset • If left untreated is fatal within a few weeks or months

Types: Acute Myeloid Leukemia (AML) Acute Lymphoblastic leukemia (ALL)

• B-cell Leukemias are more common than T-cell Leukemias.Groups: Childhood (< 15 years) > 80% ALL

Adult (> 15 years) > 80% AMLElderly (> 60 years)

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1.Acute Myeloid Leukemia:PATHOPHYSIOLOGY:• A single myeloblast accumulates genetic

changes which "freeze" the cell in its immature state and prevent differentiation.

• when such a "differentiation arrest" is combined with other mutations which disrupt genes controlling proliferation, the result is the

uncontrolled growth of an immature clone of cells, leading to the clinical entity of AML.

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• The epigenetic induction of dedifferentiation by genetic mutations that alter the function of epigenetic enzymes, such as the DNA demethylase, TET2 and the metabolic enzymes IDH1 and IDH2,which lead to the generation of a novel oncometabolite, D-2-Hydroxyglutarate, which inhibits the activity of epigenetic enzymes such as TET2.

• The hypothesis is that such epigenetic mutations lead to the silencing of Tumor supressor genes and/or the activation of proto-oncogenes.

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Signs and Symptoms:• A drop in red blood cell count (anemia) causes fatigue,

paleness, and shortness of breath.

• Lack of platelets can lead to easy bruising or bleeding with minor Trauma.

• General symptoms include fever, fatigue, weight loss or loss of appetite, Petechiae, bone and joint pain, and persistent or frequent infections.

• Enlargement of the Spleen, Lymph node swelling. The skin is involved about 10% of the time in the form of Leukemia cutis.

• Sweet's syndrome.

• Swelling of the Gums, Chloroma.11

Diffusely swollen gums Chloroma

Petechiae Leukemia CutisSweet’s syndrome

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TREATMENT

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1.Chemotherapy: i. Induction therapy:

• With Cytarabine and an Anthracycline (Daunorubicin).

• "7+3” (or "3+7")= Cytarabine is given as a continuous i.v. infusion for 7consecutive days while the Anthracycline is given for 3 consecutive days.

• Other alternative induction regimens, including high-dose cytarabine alone or investigational agents, may also be used.

• For very elderly patients options may include less intense chemotherapy or palliative care.

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a)Mechanism of action of Cytarabine:• Inhibition of DNA replication in leukemic cells at

G1/S checkpoint leading to blockade of progression of some Leukemic cells into

S phase.• Rapidly converts into cytosine Arabinoside

triphosphate, which damages DNA when the cell cycle holds in the S phase(synthesis of DNA).

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• 1.5- 3mg/kg. i.v. twice a day for 7days.• Less than 10% of injected dose is excreted

unchanged in the urine in 12- 24 hrs.• Only 20% of drug reaches the circulation in oral

administration.

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Side effects:• Cerebellar toxicity when given in high doses,

which may lead to Ataxia.• Granulocytopenia and other impaired body

defenses, which may lead to infection and Thrombocytopenia, which may lead to Hemorrhage.

• Leukopenia, Anemia, GI disturbances,  Stomatitis, Conjunctivitis, Pneumonitis, fever, and Dermatitis, Palmar-plantarerythrodysesthesia

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b)Mechanism of action of Daunorubicin:• Interacts with DNA by intercalation and

inhibition of macromolecular biosynthesis. This inhibits the progression of the enzyme Topoisomerase II, which relaxes supercoils in DNA for Transcription.

• Daunorubicin stabilizes the Topoisomerase II complex after it has broken the DNA chain for replication, preventing the DNA double helix from being resealed and thereby stopping the process of Replication.

• Maximum action in S phase but toxicity in G2 Phase. 18

• Intravenous infusion. Should not be administered intramuscularly or subcutaneously, since it may cause extensive tissue necrosis.

• It should also never be administered intrathecally (into the spinal canal), as this will cause extensive damage to the nervous system and may lead to death.

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Side effects:• Sores in mouth and lips.• Swelling of feet and lower legs.• Cough, fever, irregular heartbeat,• Hematologic: cause significant reduction in all

bone marrow celllines for 1-2 weeks after therapy. Severe myelosuppression may result in superinfection, hemorrhage, and/or death.

• Cardiovascular: Develop Heart failure.• Dermatological: Alopecia, Urticaria,

Hyperpigmentation of skin and nails.• GIT: Nausea, or vomiting, Diarrhea, Stomatitis.• Local:Local tissue inflammation, Thrombophlebitis

and Necrosis. 20

Alopecia

Thrombophlebitis Hyperpigmentation

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ii. Consolidation: Good-prognosis leukemias, will undergo an

additional 3 to 5 courses of intensive chemotherapy.

• High risk of relapse, allogeneic stem cell transplantation is usually recommended if the patient is able to tolerate a transplant and has a suitable donor.

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Relapsed AML• For patients with relapsed AML, the only

proven potentially curative therapy is a hematopoietic stem cell transplant, if one has not already been performed.

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2.Acute Lymphocytic Leukemia: Pathophysiology:• By damage to DNA that leads to uncontrolled cellular

growth and spreads throughout the body.• Damage can be caused through the formation of

fusion genes, as well as the deregulation of a proto-oncogene via juxtaposition of it to the promoter of another gene, e.g. the T-cell receptor gene.

• This damage occurs naturally during mitosis or other normal processes.

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Signs and Symptoms:• Laboratory tests that might show abnormalities in blood

count tests, renal function tests, electrolyte tests, and liver enzyme tests.

• Generalized weakness and fatigue, Dizziness• Anemia• Frequent or unexplained fever and infection• Weight loss and/or loss of appetite• Excessive and unexplained bruising• Bone pain, joint pain (caused by the spread of "blast" cells to

the surface of the bone or into the joint from the marrow cavity)

• Breathlessness• Enlarged lymph nodes, liver and/or spleen• Pitting edema (swelling) in the lower limbs and/or abdomen• Petechiae.

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Treatment:I.Chemotherapy: i. Induction therapy:

Combination of Prednisolone or Dexamethasone, Vincristine, Asparaginase and Daunorubicin is used to induce remission.

• Central nervous system prophylaxis can be achieved via irradiation, Cytarabine or liposomal Cytarabine.

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a)Mechanism of action of Vincristine:• Blocks cells in Mitosis.• Binds to β Tubulin and blocks its ability to

polymerize with alpha-Tubulin into microtubules.

• Metabolism occurs in liver and metabolites are excreted in the bile.

• Intravenously administered.• Elimination half life is 1-20hrs.

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Side effects:• Peripheral Neuropathy.• Head ache, Jaw pain, Joint pain, Stomach

cramps, weakness, Hallucinations, Unconsiousness.

• Skin rash• Nausea and Vomiting.

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b)Mechanism of action of Prednisolone:Two hypothesisApoptosis is achieved via activation of death

receptors.(Fas & TNF receptor)• Fas ligand(FasL) binds Fas & induces receptor

trimerization & the recruitment of Procaspase-8 via the adaptor protein(FADD)

• Upon autocatalysis & activation, Caspase-8 stimulates apoptosis.

• It directly cleaves & activates Caspase-3 & it cleaves the proapoptotic Bcl-2 family member(Bid).

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• The proapoptotic Bcl-2 protein,Bax translocates to the mitochondria in response to the death stimuli promotes release of Cytochrome C.

• Truncated Bid(tBid) also translocates to mitochondria upon activation by Caspase-8, where it stimulates Cytochrome C release & activation of Caspase-9.

• The subsequent activation of effector Caspases, Caspase-3, Caspase-6 & Caspase-7 leads to cleavage of cytoplasmic targets, causing cell shrinkage,DNA fragmentation & eventually apoptosis.

Repression of Transcription factor activity. 30

c)Mechanism of action of Dexamethasone:• The effect on lymphoid cells includes G1 phase

cell cycle arrest and apoptosis. • Upregulation of Promyelocytic Leukemia

Protein(PML),its complex formation with Protein kinaseB or Akt and a PML-dependent Akt dephosphorylation.

o PML protein is involved in negative regulation of PI3K signaling through dephosphorylation of Akt. PML protein forms nuclear bodies or PML Oncogenic Domains(POD). PML and PODs have been implicated in the negative regulation of cell proliferation. 31

• Multiple proapoptotic signals have been shown to be dependent on PML, including caspase-independent cell death.

• The main sideeffect is increased blood sugar level and Bone thinning.

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d)Mechanism of action of Asparginase:• The rationale behind asparaginase is that it takes

advantage of the fact that ALL leukemic cells and some other suspected tumor cells are unable to synthesize the non-essential amino acid asparagine, whereas normal cells are able to make their own asparagine

• Thus leukemic cells require high amount of asparagine. These leukemic cells depend on circulating asparagine. Asparaginase, however, catalyzes the conversion of L-asparagine to aspartic acid and ammonia. This deprives the leukemic cell of circulating asparagine, which leads to cell death. 33

Symptoms:• Hypersensitivity reaction.• Coagulopathy. • Bone marrow suppression is common but only mild to

moderate, rarely reaches clinical significance and therapeutic consequences are rarely required.

•  pancreatitis.

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ii. Consolidation: Use Vincristine, Cyclophosphamide, Cytarabine,

Daunorubicin, Etoposide, Thioguanine or Mercaptopurine given as blocks in different combinations.

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a)Mechanism of action of Cyclophosphamide:• Phosphoramide mustard introduce alkyl

radicals into DNA strands with interference with DNA replication by forming DNA crosslinkage.

• Well absorbed orally. Side effects:• Urinary bladder toxicity.• Myelodysplasia.• Pulmonary fibrosis.• Hypogammaglobulinemia.• Opportunistic infection.• Alopecia.• Hyperpigmentation of the Skin.

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b)Mechanism of action of Etoposide:• Etoposide forms a ternary complex

with DNA and the topoisomerase II enzyme. • It is given intravenously or orally in capsule

form. If the drug is given i.v., it must be done slowly over a 30- 60min period because it can lower blood pressure as it is being administered. Blood pressure is checked often during infusing, with the speed of administration adjusted accordingly.

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Side effects:• Low blood pressure• Hair loss• Pain and or burning at the i.v.site• Constipation or diarrhea• Bone marrow suppression, leading to:o Allergic-type reactionso Rasho Fever.

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c)Mechanism of action of Mercaptopurine:• Converted in the body to corresponding

Monoribonucleotides, which inhibits the conversion of Inosine monophosphate to Adenine and Guanine nucleotides.

• Incomplete absorption through oral administration(10-50%).

• Intravenous administration is preffered.

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d)Mechanism of action of Thioguanine: TGN are toxic to cells by:Incorporation into DNA during the synthesis

phase(S-Phase) of the cell.Through inhibition of the GTP-binding protein(G

protein) Rac1, which regulates the Rac pathway.

Incooperation into RNA.• Plasma half life is short.• Excreted through Kidneys in Urine.

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Side effects:• Leukopenia & Neutropenia.• Thrombocytopenia.• Anemia.• Anorexia.• Nausea & Vomiting.• Hepatotoxicity.

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iii. Maintainance:• With 6- Mercaptopurine. In some cases

combined with Vincristine and Prednisolone.• Lasts for about 2 years.

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II. Radiation therapy:• Is used on painful bony areas, in high disease

burdens, or as part of the preparations for a bone marrow transplant

• Whole-brain prophylaxis radiation used to be a common method in treatment of children’s ALL.

• Recent studies showed that CNS chemotherapy provided results as favorable but with less developmental side-effects.As a result, the use of whole-brain radiation has been more limited.

• Most specialists in adult leukemia have abandoned the use of radiation therapy for CNS prophylaxis, instead using intrathecal chemotherapy

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III.Biological therapy:• For relapsed ALL, aiming at biological targets

such as the proteasome, in combination with chemotherapy, has given promising results in clinical trials.

• In ongoing clinical trials, a CD19-CD3 bi-specific Monoclonal Murine antibody, Blinatumomab, is showing great promise.

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3.CHRONIC MYELOGENOUS LEUKEMIA:Pathophysiology:• Chromosomal translocation.• Transcription.• Translation.• Dimerization.• Trans – phosphorylation.• Activation of signaling cascade.• Proliferation.• Cell survival.• Altered stromal layer.• Expansion of leukemic cells in the bone marrow.

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Asymptomatic (50% of patients) Fatigue Weight loss Abdominal fullness and anorexia Abdominal pain, esp splenic area Increased sweating Easy bruising or bleeding Splenomegaly (95%) Hepatomegaly (50%)

CLINICAL PRESENTAITON OF CMLCLINICAL PRESENTAITON OF CML

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TREATMENT:1) Control & prolong chronic phase (non-curative): Bcr-Abl tyrosine-kinase inhibitors: Imatinib, Dasatinib, Nilotinib and Radotinib:• Imatinib inhibit the progression of CML in the

majority of patients (65–75%) .• Dasatinib, blocks several further oncogenic

proteins, in addition to more potent inhibition of the BCR-ABL protein.

• Nilotinib & Radotinib joined the class of novel agents in the inhibition of the BCR-ABL protein.

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Alpha- interferon:• MOA is still unclear.Wheather it is because of

direct antiproliferative or apoptosis effects.

Chemotherapy:• Drugs like Cytarabin is used.

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2)Eradicate malignant Clone (curative):Allogeneic BM/stem cell transplantation:

• The only curative treatment for CML is a bone marrow transplant or an Allogeneic stem cell transplant.

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1V. CHRONIC LYMPHOCYTIC LEUKEMIA:Pathophysiology:• Affects developing B-Lymphocytes. In people with

CLL, lymphocytes undergo a malignant change and become Leukemic cells.

• The molecular pathogenesis is a complex, multistep process leading to the replication of a malignant clone of B-Lymphocytes. While some steps in this pathway have been elucidated, many remain unknown.

•

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Signs and symptoms:• Swollen lymph nodes (glands) in the neck, under

the arms or in the groin, due to collections of lymphocytes in these areas,

• Pain or discomfort under the ribs on the left side, due to an enlarged spleen,

• Anaemia, due to a lack of red cells, causing persistent tiredness, dizziness, paleness, or shortness of breath when physically active,

• Frequent or repeated infections and slow healing, due to a lack of normal white blood cells,

• Increased or unexplained bleeding or bruising, due to a very low platelet count,

• Excessive sweating at night,• Unintentional weight loss.

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Treatment:• CLL is treated by chemotherapy, radiation

therapy, biological therapy, or bone marrow transplantation.

• An initial treatment regimen that contains Fludarabine and Cyclophosphamide has demonstrated higher overall response rates and complete response rates.

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Mechanism of action ofFludarabine:• It inhibits DNA synthesis.• Several enzymes involved in DNA synthesis

are targets for inhibition.• F-ara-ATP competes with normal

Deoxynucleotide, Deoxyadenosine Tri phosphate(dATP), inhibiting directly DNA polymerases.

• Inhibit DNA primase, Ribonucleotide reductase• Together these actions inactivate completely

the DNA synthesis – Apoptosis.54

• Administered intravenously.• Half life is 10hrs.• Renal excretion.Side effects:• Thrombocytopenia.• Peripheral Neuropathy.• Acute hemolytic Anemia.• Pneumonitis,etc.

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Hairy Cell Leukemia:• Presence of mononuclear cells with hairy

cytoplasmic projections in the Bone marrow, peripheral Blood and Spleen. Molecular analysis of these cells assigned B-cell origin expressing CD19, CD20 and CD22 antigen.

• Characterised clinically by the manifestations due to Reticuloendothelial organs.

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Signs:• Pancytopenia.• Hairy cells in Blood and Bone marrow which

are positive for TRAP.

Treatment:• Alpha-Interferon therapy.• Splenectomy.

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References:1. KD Tripathi. Essentials of Medical Pharmacology.

Jaypee brothers Medical Publishers(P)LTD;6:820-842.

2. Bruce Alberts, Alexander Johnson, Julian Lewis,etal. Molecular Biology of the Cell. Garland science,Taylor & Francis group of Publications;5:1219-1232.

3. Goodman & Gilman. The Pharmacological basics of Therapeutics. Medical publishing division;11:1326-1345.

4. Harsh mohan.Text book of Pathology.Jaypee brothers Medical Publishers(P)LTD;5:414-423.

5. Internet source. 59

THANK YOU

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