Leukemias Flashcards
CML rseults from
acquired mutations + proliferation of myeloblasts
what is characterized by the philadelphia chromosome
CML
what is the philadelphia chromosome
Translocation between long arms of chromosomes 9 and 22 = joining of ABL gene of chromosome 9 and BCR gene of chromosome 22 = formation of BCR-ABL fusion oncogene
Results in super long chromosome 9 and shorter chromosome 22 (philadelphia chromosome, Ph+)
joining of ABL gene of chromosome ___ and BCR gene of chromosome ___= formation of BCR-ABL fusion oncogene
9, 22
what does the BCR-ABL gen cause
production of BCR-ABL protein = abnormal TK that has an ATP bindng site that can transfer phosphate groups to protein substrate, causing CML cells proliferate and avoid apoptosis
CML S/S
splenomegaly
suppression of hematopoiesis
leukocytosis or leukostasis
up to 50% asumptomatic due to initial indolent phase of disease
what is leukocytosis
WBC >25
what is leukostasis
WBC >100
dx of CML requires
cytogenetics for philadephia chromosome
molecular testing of QPCR
staging
describe the 3 stages of CML and the amount of myeloblasts
chronic phase <10%
accelerated phase 10-20% or persistent leukocytosis, thrombocytosis, thrombocytopenia, splenomegaly unresponsive to tx
blast crisis >20%
leukostasis in CML requires
asap hydroxyurea to rapidly lower WBCs + allopurinol to prevent tumor lysis syndrome
MOA of BCR-ABL TKis
competitively binds to ATP binding site on BCR-ABL kinase = inhibits phosphorylation of proteins involved with signal transduction for CMl clone proliferation
name the 3 TKis for CML
imatinib, dasatinib, nilotinib
which TKis should be taken with food
imatinib, dasatinib
which TKis should be taken without food? why
nilotinib - increases bioavailability
which TKi is acid dependent absorption
dasatinib
AEs of BCR-ABL TKis
myelosuppression
fluid retention
N/V
QT interval prolongation
hepatotoxicity
drug rash
diarrhea
which TKis has a black box warning for QT prolongation
nilotinib and dasatinib- baseline ECG rec
which TKi is most associated with fluid retention
dasatinib
reasons for Tki failure
compliance
drug interactions
resistance- point mutation in ABL kinase domain that activates it
what is the only cure for CML
allogenic stem cell transplant
can CML pts ever d/c TKis
yes if they’ve been on BCR-ABL TKi for at least 5yrs + undetectable disease for 2yrs consecutively (monitor QPCR q1mth)
- may result in 50% relapse rate
why are allogenic stem cell transplants rarely done in CML
cause TKis work fine
not everyone has a donor + transplant has many toxicities
ALL sx
B sx like weight loss, night sweats, fever
pain in joints/ bones
CNS manifestations
cytopenias
what is required for an ALL diagnosis
20% lymphoblasts
chemo for ALL is usually the ______ protocol
modified Dana-Farber
in addition to chemo, ALL usually adds
BCR-ABL TKi therapy (gene is present in 25% cases)
drugs for LL
asparaginase
methotrexate
chemo
asparaginase MOA in ALL
asparaginase hydrolyses all L-asparagine to L-aspartic acid and ammonia so the ALL cells have nothing to use to repro as they can’t make themselves
asparaginase AEs
severe hypersensitivity rxns- asparaginase from E coli has the highest incidence
Prior intradermal test dose is recommended
methotrexate is used with _________ intrathecally as ______in ALL
chemo
CNS prophylaxis
methotrexate MOA
folate antagonist- inhibits dihydrofolate reductase required to convert folic acid to tetrahydrofolate (required for purine and thymidylate synthesis)
what is an important factor to make sure methotrexate is safe
keep urine alkaline with sodium bicarb so it doesn’t precipitate and cause kidney damage
- start sodium bicarb PO/IV day before infusion
methotrexate therapy usually requires ____ rescue
leucovorin
how is leucovorin rescue used with methotrexate
Must receive doses of leucovorin q6h until lvls undetectable to rescue pt from life threatening myelosuppression and other toxicities
methotrexate AEs
myelosuppression, organ toxicities (nephrotoxicity, hepatotoxicity, neurotoxicity)- pts require rescue leucovorin
TLS results in what chem anomalies
hyperuricemia, hyperkalemia, hyperphosphatemia, hypocalcemia
RFs for TLS
large bulky tumor, high LDH or WBCs, higher baseline SCr or uric acid
high chemo
aggressive lymphoma or leukemia
sx of TLS
N/V, acute kidney injury (↑SCr), ↓urine output, edema, lethargy, HPTN, ECH changes (arrhythmias), muscle twitching, cramping, numbness, weakness, tetany, confusion and seizures
drugs for TLS prevention
allopurinol
rasburicase
how does allopurinol treat TLS
inhibits xanthine oxidase (enzyme responsible for formation of uric acid)
how does rasburicase treat TLS
recomb urate-oxidase enzyme that converts uric acid to allantoin + degrades uric acid already formed
how to treat asymptomatic hyperkalemia from TLS
oral or rectal sodium polystyrene sulphonate
how to treat symptomatic hyperkalemia from TLS
rapid acting insulin and 25% dextrose infusion
what is the most common form of acute leukemia
AML
sx of AMl
Rapidly fatal if not treated
Cytopenias- drop in other cell lines (pancytopenia)
Anemia: fatigue, malaise, weakness
Thrombocytopenia: easy bruising, petechiae, ecchymosis, heavy and/ or long menses, bleeding like epistaxis, gingival bleed, conjunctival hemorrhage
Neutropenia: infection, s/s may be absent due to nonfunctioning malignant WBC clones
High myeloblast count
diganosis of AML is
> 20% myeloid blasts
what are some predictors of outcome in adult ML
redictors of outcomes in adult AML
Age: Outcomes better in <60yrs
Performance status: fitter pts do better
Duration of first remission
Cytogenetics and molecular abnormalities- MOST IMPORTANT
treatment plan for AML
Induction chemo → consolidation chemo → allogeneic stem cell transplant
what is usually induction chemo for AML
7+3
7 days of continuous infusion cytarabine (rash common)
3 days of IV push anthracycline (idarubicin or daunorubicin)
+ midostaurin for FLT3 positive AML
T or F: AML pts undergoing 7+3 still require allopurinol to prevent TLS
T- though TLS not as common as in ALL
consolidation therapy in AAML is done with
HIDAC- high dose ARA-C (cytarabine)
HIDAC AEs
ocular toxicity (Excessive tearing, pain, photophobia, sensation of foreign body)
cerebellar toxicity
how to treat ocular toxicity caused by HIDAC for AML
steroid eyedrops (dexamethasone or prednisolone) for duration of HIDAC therapy + 48hrs after last dose
list some purposes of an allogenic HSCT
Rescue recipient from myeloablative therapy
Replace abnormal hematopoietic component
Establish graft vs leukemia (tumor) effect where donor cells destroy residual malignant cells in host - advantage over autologous HSCT
stem cell sources for allogenic HSCT
boen marrow
peripheral blood
ubilical cord blood
