INTRODUCTION TO ANTINEOPLASTIC AGENTS Flashcards
Top10 Cancer Sites
Estimated NewCases 2015
EstimatedDeaths 2015
1. Breast Cancer (Female) 231,840 40,290 2. Lung and Bronchus Cancer 221,200 158,040 3. ProstateCancer 220,800 27,540 4. Colon and Rectum Cancer 132,700 49,700 5. Bladder Cancer 74,000 16,000 6. Melanoma of the Skin 73,870 9,940 7. Non-Hodgkin Lymphoma 71,850 19,790 8. Thyroid Cancer 62,450 1,950 9. Kidney and Renal Pelvis Cancer 61,560 14,080 10. Endometrial Cancer 54,870 10,170 All Cancer Sites 1,658,370 589,430
Alkylating Agents
nitrogen mustards
cyclophosphamide
ifosfamide
Alkylating Agents
alkyl sulfonate
busulfan
Alkylating Agents
platinum coordination complexes
cisplatin
Natural Products
vinca alkaloids
vinblastine
vincristine
Natural Products
taxanes
paclitaxel
Natural Products
epipodophyliotoxins
etoposide
Natural Products
antibiotics
bleomycin
doxorubicin
Natural Products
eznymes
l asparaginase
Antimetabolites
folic acid analogs
methotrexate
Antimetabolites
pyrimidine analogs
fluorouracil
Antimetabolites
purine analogs
mercaptopurine
Differentiating agents
tretinoin
biological response modifiers
Interferon-alfa
Interleukin-2
Immunomodulators
Thalidomide
Rescue agents
- Leucovorin
* Mesna
Protein tyrosine kinase inhibitors
dasatinib
erlotinib
imatinib
lapatinib
proteasome inhibitors
bortezomib
monoclonal abs
bevacizumab
cetuximab
rituximab
trastuzumab
Agents used to minimize adverse effects
erythropoietin
filgrastim
ondandetron - serotonin antagonists
Cancer Treatment Modalities
- Chemotherapy
- Immunotherapy
- Radiation Therapy
- Surgery
- Targeted Therapies
- Transplantation
- Vaccines
- Combinations are the norm
Primary Induction Therapy
- The main treatment that provides the best possible outcome
* Also called first-line therapy
NeoadjuvantTherapy
- Treatment given BEFORE primary induction therapy in order to improve outcome
- E.g., Chemo or radiation to shrink a tumor before surgery
Adjuvant Therapy
•Additional therapy given CONCOMITANTLY or AFTER primary induction therapy in order to reduce the probability of relapse
g0 phase
resting
m phase
mitosis
g1 phase
synthesis of components needed of dna synthesis
s phase
synthesis of dna
g2 phase
synthesis of componeneint needed fo ritosis
cell phases in order
g0 g1 s g2 m
checpoints for dna
after g1
befro s phase finishes
end of g2
before m phase finishes
Cycling Out of Control
- In many forms of cancer, proteins orpathways involved in regulating the checkpoints between the phases of the cell cycle may be absent or mutated
- For example: p53, CDKs
- Aberrations in checkpoint regulation result in uncontrolled and unregulated cell proliferation
- Cell cycle specific vs. cell cycle nonspecific
Antimetabolites (S phase)
5-fluorouracil
6-mercaptopurine
Methotrexate
Antitumor antibiotics (S-G2phase)
bleomycin
Taxanes(M phase)
Paclitaxel
Vincaalkaloids (M phase)
Vinblastine
Vincristine
Topoisomerase II Inhibitors (Epipodophyllotoxins, S-G2 phase
Etoposide
Cell cycle nonspecific agents
Alkylating agents
Cyclophosphamide
Ifosphamide
Busulfan
Cell cycle nonspecific agents
Anthracyclines
Doxorubicin
Cell cycle nonspecific agents
Platinum analogs
Cisplatin
Growth Fraction and Tumor Growth Rate
- Growth fraction = the ratio of proliferating cells to resting cells (G0)
- Growth fraction is a determinant of responsiveness to chemotherapy
Cells with high growth fraction
- Bone marrow
- GI tract
- Hair follicles
- Sperm-forming cells
higher growth fraction =
shorter doubling time
lower growth fraction =
longer doubling time
Growth Fraction and Therapeutic Response
- The initial growth rate of most solid tumors is rapid but decreases over time
- Burkittlymphoma (high growth fraction; curable by chemotherapy) vs. colorectal carcinoma (low growth fraction; chemotherapy has minor activity)
- Some disseminated tumors can be cured by single-agent chemotherapy
- The growth fraction of solid tumors can be increased by reducing the tumor burden (i.e., surgery or radiation)
Log Cell Kill Hypothesis
- A fraction (not an absolute number) of cells are killed
- A three-log cell kill eliminates 99.9% of cells:
- 1012to 109cells
- 106to 103cells
Therapeutic Balance: Efficacy vs. Toxicity
•Challenge:
provide dose that is therapeutic without being (too) toxic
•Antineoplastic drugs harm both cancerous tissues and healthy tissues
•Not all drug regimens are appropriate for all patients
Therapeutic Balance: Efficacy vs. Toxicity
•Factors to consider:
- Renal and hepatic function
- Bone marrow reserve
- General performance status
- Concurrent medical problems
- Patient willingness
Primary resistance
- An absence of response on the first drug exposure
* Thought to be due to genomic instability
Acquired resistance
- Develops in response to exposure to a given antineoplastic agent
- Often highly specific to a single drug, or class of drugs, and is usually due to an increased expression of one or more genes
Examples of single agent resistance pathways include:
- decreased drug transport into cells
- reduced drug affinity due to mutations or alterations of the drug target
- increased expression of an enzyme that causes drug inactivation
- increased expression of DNA repair enzymes for drugs that damage DNA
Multidrug resistance and ATP-dependent Transporters
mechanism
- ATP-dependent transporter gene amplification in neoplasms confers resistance to a broad range of agents used in cancer treatments
- The P-glycoprotein is an ATP-dependent efflux pump that actively pumps antineoplastic agents out of cells (MDR1gene)
Multidrug resistance and ATP-dependent Transporters
drugs
Anthracyclines, vincaalkaloids, etoposide, paclitaxel, and dactinomycin
Toxicity of Antineoplastic Agents
- The lack of neoplastic specificity for chemotherapeutic drugs is a major limiting factor in the treatment of cancer
- Rapidly proliferating normal tissues (tissues with high growth fractions) are the major sites of toxicity
- bone marrow, gastrointestinal tract, hair follicles, buccalmucosa, sperm forming cells
- Many antineoplastic agents are mutagens themselves and can give rise to neoplasms years after treatment (e.g., alkylating agents have caused AML and ALL)
Common Adverse Effects
- Nausea
- Vomiting
- Fatigue
- Stomatitis
- Alopecia
- Myelosuppression –can lead to impaired wound healing and predisposition to infection
- Low sperm counts and azoospermia
- Depressed development of children exposed to antineoplastic agents
- Nausea
- Vomiting
- Fatigue
- Stomatitis
- Alopecia
Occur during therapy with nearly all classicantineoplastic agents
Minimizing Adverse Effects
- Choose the route of administration that minimizes systemic toxicity as much as possible
- Pharmacologic agents that help decrease adverse effects
- Hematopoietic agents for neutropenia, thrombocytopenia, and anemia
- Serotonin receptor antagonist (ondansetron) and other drugs for emetogeniceffects
- Bisphosphonates to delay skeletal complications
- Rest and recovery
inhibit purine ring biosynthesis
inhibit dna synthesis
6 mercaptopurine
6 thiglianine
inhibit dihydrofolate reduction, block thymidylate and purine synthesis
alimta
methotrexate
block topoisomerase function
camptothecins etoposide teniposide dalincrubicin doxorubicin
block activites of signaling pathways
protein tyrosine kinase inhibitors
antibodies