CA Pharm Flashcards
Five main classes of cancer drugs
alkylating agents, antimetabolites, natural products, antibodies, miscellaneous
Oncogene
gene that positively influences tumor growth
Tumor suppressor
gene that negatively influences tumor growth
Activation of oncogenes overrides which check point?
G1 arrest
Inactivation of tumor suppressor genes overrides which check point?
G2 arrest
Treatment process for primary chemotherapy
chemo! for advanced CA and metastatic disease
Goals of primary chemotherapy
relieve tumor-related symptoms, improve quality of life, prolong time to tumor progression
CAs curable by primary chemotherapy
Hodgkin’s and NHL, Burkitt’s lymphoma, Wilms tumor, embyonal rhabodmyosarcoma, choriocarcinoma, germ cell cancer, acute lymphoblastic leukemia
Neoadjuvant chemotherapy treatment process
chemo -> surgery -> chemo
Goal of neoadjuvant chemo
reduce tumor size to make resection easier and more effective, follow up with chemo to prevent relapse
Adjuvant chemotherapy treatment process
surgery -> chemo
Goal of adjuvant chemo
reduce incidence of local and systemic recurrence, improve survival of patients
Growth fraction definition
ratio of proliferating to G0 cells
Growth fraction can determine what about a tissue?
responsiveness to chemotherapy; higher growth fraction, more curable
Cell types with high growth fraction
bone marrow, GI tract, hair follicles, sperm-forming cells
How can growth fraction of solid tumors be increased?
reducing tumor burden via surgery or radiation
Main challenge in achieving therapeutic balance during treatment
therapeutic without being too toxic
Pharmacokinetics of antineoplastic therapy
first-order, given dose of a drug destroys a constant fraction of cells rather than an absolute number
High-dose intermittent therapy allows what for normal tissues
recovery
Common routes of chemo administration
IV and PO
Why should alternative drug administration routes be considered for some patients?
can reduce systemic toxicity and increase drug delivery
Pharmacologic sanctuaries
regions where tumor cells are less susceptible to antineoplastic drugs (CNS)
Alternative chemo admin routes
intracavity, intrathecal, intraventricular, intraarterial, topical, isolated limb perfusion
Advantages of combination chemotherapy
provides maximal cell killing, effective against a broader range of cell lines in heterogenous tumors, may delay or prevent development of drug-resistant tumors
Primary chemotherapeutic drug resistance
occurs in the absence of prior exposure, often due to the genetic instability of CA and p53 mutations
Acquired chemo drug resistance
develops in response to exposure to a given drug, due to genetic change
Examples of acquired drug resistance
decreased drug transport into cells, reduced drug affinity due to mutations in target, increased expression of enzyme that inactivates drug, increased expression of DNA repair enzymes for drugs that damage DNA
P-glycoprotein is present in which tissues?
tissues with barrier functions such as kidney, liver, GI tract; blood-brain barrier and placental-blood barrier
Role of PGP
pumps drug out of a cell, may indicate inherent or primary resistance or acquired resistance
Rapidly proliferating tissues that demonstrate major sites of toxicity
bone marrow, GI tract, hair follicles, oral mucosa, sperm forming cells
How can adverse drug effects be minimized?
choosing a route that minimizes systemic toxicity and providing pharmacologic agents that can decrease adverse effects
Hematopoietic agents can decrease what adverse effects?
neutropenia, thrombocytopenia, anemia
Serotonin receptor antagonists can decrease what adverse effects?
emetegoenicity
Bisphosphonates can delay what complications?
skeletal complications
Five major types of alkylating agents
nitrogen mustards, nitrosoureas, alkyl sulfonates, methylhydrazine derivatives, triazines **also platinum compounds
What type of alkylating agent is cyclophosphamide?
nitrogen mustard
What type of alkylating agent is carmustine?
nitrosourea
What type of alkylating agent is busulfan?
alkyl sulfonates
What type of alkylating agent is procarbazine?
methylhydrazine derivative
What type of alkylating agent is dacarbazine?
tirazines
What type of alkylating agent is cisplatin?
platinum compounds
Most widely used alkylating agent
cyclophosphamide
MOA of alkylating agents
form covalent linkages within DNA, prevents the unwinding of DNA so cells cannot make RNA and DNA; non cell cycle specific
What enzyme activates cyclophosphamide?
CYP2B
What are the cytotoxic metabolites of cyclophosphamide?
acrolein, phosphoramide mustard
Side effect of acrolein
hemorrhagic cystitis
Drug that inactivates acrolein
Mesna
Acute toxicity of alkylating agents
nausea and vomiting (may pretreat with zofran) and delayed toxicities such as bone marrow depression, alopecia, nephrotoxicity, mucosal ulceration, intestinal denudation
AE associated with cisplatin
renal tubular damage, ototoxicity
AE associated with busulfan
pulmonary fibrosis
Main categories of antimetabolites
folic acid analogs, pyrimidine analogs, purine analogs
MOA of antimetabolites
block or subvert pathways involved in cell replication, cell cycle specific
Methotrexate is an analog of what?
folic acid
Fluorouracil is an analog of what?
pyrimidines
Mercaptopurine is an analog of what?
purine
What enzyme does methotrexate inhibit?
dihydrofolate reductase
What other diseases can methotrexate be used to treat?
rheumatoid arthritis and psoriasis
What drug is used in combination therapy with methotrexate?
leucovorin, used to rescue normal cells
Leucovorin is an analog of what?
methylene FH4
Active compound of fluorouracil
FdUMP
FdUMP action
covalently binds thymidylate synthetase and blocks synthesis of thymidylate; incorporated into DNA synthesis
Enzyme that metabolizes mercaptopurine
hypo-xanthine-guanine phosphoribosyl transferase (HGPRT)
Active form of mercaptopurine
6-thioinosinic acid
Enzyme that biotransforms 6-thioinosinic acid
xanthine oxidase
What drug should be used in supportive care of leukemia to prevent hyperuricemia?
allopurinol
What portion of the cell cycle are antimetabolites specific to?
S-phase
Common administration routes of antimetabolites
oral, IV, intrathecal
Common toxicities of antimetabolites
diarrhea, myelosuppression, nausea, vomiting, immunosuppression, thrombocytopenia, leukopenia, hepatotoxicity
Where are natural antineoplastic agents found?
extracted from plants/trees, isolated from cultures of bacteria, enzymes
Vinca alkaloids MOA
bind to beta-tubulin and inhibit microtubule assembly (depolarization), specific to M phase
Common AE of vinca alkaloids
alopecia and bone marrow depression
AE of vinblastine vs vincristine
Vinblastine - myelosuppression
Vincristine - cumulative neuro toxicities
Taxanes MOA
Binds to beta-tubulin and stabilize microtubule formation, mitosis inhibition
Paclitaxel AE
hypersensitivity in hands and toes, change in taste
Docetaxel AE
hypersensitivity, neutropenia, hair loss
Function of topoisomerase I
cut one strand to dsDNA to relax and reanneal strand
Function of topoisomerase II
cut both strands of double-stranded DNA, coil and uncoil DNA supercoils
Drugs that inhibit topoisomerase I
camptothecins
Drugs that inhibit topoisomerase II
epipodophyllotoxins and anthracycline abx
What bacteria produce anticancer antibiotics?
Streptomyces
Anthracyclins MOA
topoisomerase II inhibitor and DNA intercalation, cell cycle nonspecific
Anthracyclins AE
Produces free radicals that can lead to cardiotoxicity – dysrhythmias and heart failure
Bleomycin MOA
single and dsDNA breaks
Bleomycin AE
pulmonary toxicity resulting in pneumonitis with cough, dyspnea and inspiratory crackers
Dactinomycin MOA
intercalation of DNA
MOA asparaginase and pegaspargase
hydrolyzes circulating L-asparagine into aspartic acid and ammonia, inhibiting protein synthesis, works at G1
Toxicities associated with asparaginase and pegaspargase treatment
acute hypersensitivity (fever, chills, N/V, skin rash), increased risk of clotting and bleeding, pancreatitis, CNS toxicity
Acute promyelocytic leukemia translocation
t(15;17), creates PML-RARa fusion protein
Tretinoin MOA
binds PML-RARa and antagonizes inhibitory effect on gene transcription
BCR-ABL fusion protein results from which translocation?
t(9;22)
MOA Imatinib
inhibits ABL tyrosine kinase, inhibit RTKs PDGFR and KIT
MOA Erlotinib and gefitinib
inhibitors of EGFR, used for lung and pancreatic CA
Toxicities caused by erlotinib and gefitinib
dermatologic
Tyrosine kinase and growth factor inhibitors MOA
inhibit tyr kinase activity and growth factor receptor signaling
AE tyrosine kinase and growth factor inhibitors
acneform skin rash and hypersensitivity, N/V
Functions of interferons in CA response
inhibit cell growth, alter cell differentiation, interfere with oncogene expression, increase macrophage activity
AE of interferon therapy
bone marrow depression, neutropenia, anemia, renal toxicity, edema, arrhythmias
IL-2 MOA
increases cytotoxic killing by T cells and NK cells
Toxicity of IL-2
capillary leak syndrome
Rituximab antigen and ag function
CD20, proliferation and differentiation
Rituximab CA
NHL
Most active cytotoxic agents to malignant melanoma
dacarbazine, temozolomide, cisplatin
Biological agents used to treat malignant melanoma
IFN-a and IL-2
Nivolumab and pembrolizumab CA
malignant melanoma
Mucositis is commonly caused by which chemotherapies?
methotrexate, melphalan
Pulmonary fibrosis is commonly caused by which chemotherapies?
Bleomycin, busulfan
Peripheral neuropathy is commonly caused by which chemotherapies?
Vincristine
Ototoxicity is commonly caused by which chemotherapies?
cisplatin
Cardiotoxicity is commonly caused by which chemotherapies?
doxorubicin, daunorubicin
Nephrotoxicity is commonly caused by which chemotherapies?
cisplatin, cyclophosphamide
Hemorrhagic cystitis is commonly caused by which chemotherapies?
cyclophosphamide, ifosfamide