Biologics and targeted therapy

Question 1

Monoclonal antibody production requires two things:

Answer 1

1. a cell to that’s immortal and can continuously produce antibodies (ie a myeloma cell line) and
2. a cell that can produce antibodies to a given antigen.

Question 2

Kohler and Milstein produced the first monoclonal antibodies by injecting mice intraperitoneally with the antigen to which the ______ would be targeted. Spleens (containing the plasma cells that produced the antibodies) were harvested and then spleen cells were fused with a ____cell line immortalized to survive indefinitely in tissue culture.

Cells were cultured under conditions promoting fusion of cell membranes and then propagated under selection conditions allowing only fused cells to grow. These cells (termed _________) were then seeded by limiting dilution into tissue culture dishes to separate progeny from single cells (hence “monoclonal”), supernatants collected and tested for antibody production.

Once an appropriate MoAb is identified, it can be mass produced using biotechnology.

Answer 2

Kohler and Milstein produced the first monoclonal antibodies by injecting mice intraperitoneally with the antigen to which the MoAb would be targeted. Spleens (containing the plasma cells that produced the antibodies) were harvested and then spleen cells were fused with a myeloma cell line immortalized to survive indefinitely in tissue culture.

Cells were cultured under conditions promoting fusion of cell membranes and then propagated under selection conditions allowing only fused cells to grow. These cells (termed hybridomas) were then seeded by limiting dilution into tissue culture dishes to separate progeny from single cells (hence “monoclonal”), supernatants collected and tested for antibody production.

Once an appropriate MoAb is identified, it can be mass produced using biotechnology.

Question 3

mab =

Answer 3

monoclonal Ab (MoAb)

Question 4

ab =

Answer 4

murine MoAb

Question 5

ximab =

Answer 5

chimeric MoAb

Question 6

zumab =

Answer 6

humanized MoAb

Question 7

umab =

Answer 7

(fully) human MoAb

Question 8

MoAbs have three major mechanisms by which they lead to cell death.

Answer 8

1. The first mechanism is apoptosis. The tumor must have the target antigen to which the MoAb is directed. The MoAb binds the tumor and signals are sent to the nucleus to initiate apoptosis.
2. The second mechanism is complement-mediated cytotoxicity. The MoAb binds antigen on tumor cells, and the exposed Fc portion recruits complement, which activates the complement cascade, leading to cell death.
3. The third mechanism is via ADCC. The MoAb binds the tumor cell, and flags the tumor cell to attract immune effector cells, such as natural killer cells and cytotoxic T cells, which then kill the tumor cell. Apoptosis, complement-mediated cytotoxicity, and ADCC are mechanisms of cell killing by unconjugated antibodies.

Question 9

The tumor must have the target antigen to which the MoAb is directed. The MoAb binds the tumor and signals are sent to the nucleus to initiate

Answer 9

apoptosis

Question 10

The MoAb binds antigen on tumor cells, and the exposed Fc portion recruits complement, which activates the complement cascade, leading to cell death.

Answer 10

complement-mediated cytotoxicity

Question 11

The MoAb binds the tumor cell, and flags the tumor cell to attract immune effector cells, such as natural killer cells and cytotoxic T cells, which then kill the tumor cell.

Answer 11

ADCC

Question 12

Apoptosis, complement-mediated cytotoxicity, and ADCC are mechanisms of cell killing by unconjugated antibodies.

Answer 12

yep

Question 13

Antibodies can also be conjugated to other moieties, allowing additional mechanisms for cell killing.

_________ can be conjugated to the MoAb to deliver radiation directly to the tumor bed.

Cell death occurs to the ?

Different isotopes (such as ________131) have been used.

Answer 13

Antibodies can also be conjugated to other moieties, allowing additional mechanisms for cell killing.

Radionuclides can be conjugated to the MoAb to deliver radiation directly to the tumor bed.

Cell death occurs to the initial individual tumor cell bound to the MoAb as well as adjacent tumor cells because of the radiation effects.

Different isotopes (such as iodine-131) have been used.

Question 14

Other drugs, such as toxins or chemotherapy, can be bound to the MoAb, delivering the drugs directly to the tumor site, where they can be internalized to exert toxic effects.

what is the benefit of this method?

Answer 14

This can enable delivery of high doses of drug to the tumor with substantially lower systemic levels, thus minimizing side effects.

Question 15

Rituximab is a

1. _____ MoAb used extensively in the treatment of (3)
2. It can be used off-label use in a range of other disorders mediated by ______________
3. Rituximab is a naked (unconjugated) antibody that binds to _____, a B-cell marker, used against tumor cells that are ____positive.
4. Cell death occurs via (3).
5. Rituximab is used in combination with chemotherapy to increase ________

Answer 15

Rituximab is a

1. chimeric MoAb used extensively in the treatment of (1) lymphoma, (2) rheumatoid arthritis and (3) organ transplant rejection.
2. It can be used off-label use in a range of other disorders mediated by auto-immune mechanisms.
3. Rituximab is a naked (unconjugated) antibody that binds to CD20, a B-cell marker, used against tumor cells that are CD20-positive.
4. Cell death occurs via (1) apoptosis, (2) ADCC, and (3) complement activation.
5. Rituximab is used in combination with chemotherapy to increase efficacy.

Question 16

Tumor lysis has occurred in patients with heavy tumor burdens at the start of treatment, and rituximab should be used with caution.

Some chemotherapy regimens skip rituximab in the first cycle until tumor burden has decreased

.

Answer 16

yep

Question 17

Rituximab toxicities:

1. major toxicities include (3)
2. Rituximab is very __________, with prolonged cytopenias, including lymphopenia, with increased risk of several infections, including ________ reactivation and progressive _________ due to JC virus infection.
3. the development of (2) in which the patient develops antibodies against the MoAb, but this very rare and not clinically significant.

Answer 17

1. Major toxicities include (1) infusion-related reactions, (2) immunosuppression, and (3) tumor lysis. Infusion reactions can include hypotension, dyspnea, and fever, and are treated with supportive measures
2. Rituximab is very immunosuppressive, with prolonged cytopenias, including lymphopenia, with increased risk of several infections, including hepatitis B reactivation and progressive multifocal leukoencephalopathy (PML) due to JC virus infection.
3. the development of (1) HAMA (human anti-monoclonal antibodies) and (2) HACA (human anti-chimeric antibodies), in which the patient develops antibodies against the MoAb, but this very rare and not clinically significant.

Question 18

Epidermal growth factor receptor (EGFR) is also known as __ or __. These _______proteins are present on all cells, but may be over-expressed in certain tumor types.

they regulate ?

they are expressed in a variety of tissue including epithelial, mesenchymal and neuronal origin. When they become dysregulated it leads to proliferative advantage and malignant potential

Answer 18

Epidermal growth factor receptor (EGFR) is also known as HER1 or erbB1. These transmembrane proteins are present on all cells, but may be over-expressed in certain tumor types (such as HER2/neu in breast cancer).

they regulate normal cell growth and differentiation

they are expressed in a variety of tissue including epithelial, mesenchymal and neuronal origin. When they become dysregulated it leads to proliferative advantage and malignant potential

Question 19

Cetuximab

1. binds to cell surface ________and blocks _________
2. It was one of the earliest MoAbs developed for oncologic use and is an _________ antibody
3. it has efficacy in a variety of solid tumors including (3)
4. toxicities include (4)

Answer 19

1. binds to cell surface EGFR and blocks growth factor from binding
2. It was one of the earliest MoAbs developed for oncologic use and is an unconjugated antibody
3. it has efficacy in a variety of solid tumors including (1) colorectal cancer (2) head and neck cancer and (3) lung cancer
4. toxicities include (1) infusion related rxn (2) acneiform rash (3) asthenia (4) N/V (5) hepatoxicity

Question 20

Trastuzumab

1. targets the ______receptor (anti-p185 HER2). This receptor is over-expressed in approximately 30% of ______cancers.
2. Trastuzumab is an _______humanized mouse MoAb, with an ________ subtype.
3. Major adverse reactions of trastuzumab include __________ as seen with all MoAbs, though they are less common with trastuzumab compared to other MoAbs.

Generalized pain, asthenia and headache may occur, and supportive care is given for treatment.

__________ is not that common when trastuzumab is used as a single agent, but more so when used in combination with chemotherapy, likely due to effects of chemo.

4. Cardiotoxicity ,manifested as ___________, is a unique toxicity of MoAbs targeting the HER2/ErB2 receptor due to________________ It is exacerbated by combination with certain chemotherapy agents that are also cardiotoxins (such as ________).

Answer 20

1. targets the Her2/neu/ErbB2 receptor (anti-p185 HER2). This receptor is over-expressed in approximately 30% of breast cancers.
2. Trastuzumab is an unconjugated humanized mouse MoAb, with an IgG1 kappa subtype.
3. Major adverse reactions of trastuzumab include infusion-related reactions (hypotension, shortness of breath, edema, bronchospasm), as seen with all MoAbs, though they are less common with trastuzumab compared to other MoAbs.

Generalized pain, asthenia and headache may occur, and supportive care is given for treatment.

Myelosuppression is not that common when trastuzumab is used as a single agent, but more so when used in combination with chemotherapy, likely due to effects of chemo.

4. Cardiotoxicity (manifested as cardiomyopathy) is a unique toxicity of MoAbs targeting the HER2/ErB2 receptor due to cross-reacting epitopes on cardiac tissue. It is exacerbated by combination with certain chemotherapy agents that are also cardiotoxins (e.g. anthracyclines).

Question 21

Bevacizumab is a humanized MoAb directed against all isoforms of_____________

In non-malignant cells, it binds to its receptor on the cell surface, the receptor dimerizes and auto-phosphorylates, leading to propagation of signals to the nucleus that trigger ____________ and ___________.

In many solid tumor cells, the_____receptor is over-expressed, increasing ____signaling.

Bevacizumab therefore targets these solid tumors. The exact mechanism of action is unknown, but it has been shown that bevacizumab binds soluble _____ to disrupt interaction with its receptor, decreasing ______ signaling and ultimately decreasing _________.

Other proposed mechanisms of action include enhancing ______ cell function and immunologic functions such as ADCC and complement activation.

Answer 21

Bevacizumab is a humanized MoAb directed against all isoforms of vascular endothelial growth factor (VEGF).

In non-malignant cells, VEGF binds its receptor on the cell surface, the receptor dimerizes and auto-phosphorylates, leading to propagation of signals to the nucleus that trigger cell proliferation and angiogenesis.

In many solid tumor cells, the VEGF receptor is over-expressed, increasing VEGF signaling.

Bevacizumab therefore targets these solid tumors. The exact mechanism of action is unknown, but it has been shown that bevacizumab binds soluble VEGF to disrupt interaction with its receptor, decreasing VEGF signaling and ultimately decreasing angiogenesis.

Other proposed mechanisms of action include enhancing dendritic cell function and

Question 22

Simplified bevacizumab’s mechanism of action:

Answer 22

binding VEGF and preventing VEGF interaction with its receptor, decreasing signals downstream of the receptor and ultimately preventing angiogenesis.

Question 23

The process of ligand-receptor binding leading to receptor dimerization, auto-phosphorylation, and signal propagation, is a general mechanism for all tyrosine kinase receptors, including the EGFR and HER2.

Answer 23

yep

Question 24

Black box warning for bevacizumab

These side effects require a several week interval between surgery and initiation of therapy. Patients with certain _______ cancers are at increased risk of hemoptysis and hemorrhage.
There is also an increased risk of ____________events, including myocardial infarction and stroke. Patients at high risk include those with a history of angina, stroke and prior thrombotic events.

Other toxicities include hypertension and nephrotic syndrome, presenting with proteinuria.

Answer 24

impaired wound healing, hemorrhage, and (paradoxically) thromboembolic events

These side effects require a several week interval between surgery and initiation of therapy. Patients with certain lung cancers are at increased risk of hemoptysis and hemorrhage.
There is also an increased risk of thromboembolic events, including myocardial infarction and stroke. Patients at high risk include those with a history of angina, stroke and prior thrombotic events.

Other toxicities include hypertension and nephrotic syndrome, presenting with proteinuria.

Question 25

Most common oncologic uses of bevacizumab are in (4) In non-oncologic use, bevacizumab is also injected directly into the eye to treat _________________

Answer 25

Most common oncologic uses of bevacizumab are in (1) colorectal cancer, (2) lung cancer, (3) renal cell cancer and (4) brain cancer. In non-oncologic use, bevacizumab is also injected directly into the eye to treat wet macular degeneration.

Question 26

Tyrosine kinase inhibitors (TKIs), or “nibs,” are some of the first small molecule inhibitors used in the treatment of cancer. They work on the intracellular portion of EFGRs, targeting ______________ that affect various pathways within the cell, with the ultimate goal of inhibition o_____________. TKIs are _____agents, which is good for patient convenience, but also costly for patient finances, costing $5-8000 a month.

Answer 26

Tyrosine kinase inhibitors (TKIs), or “nibs,” are some of the first small molecule inhibitors used in the treatment of cancer. They work on the intracellular portion of EFGRs, targeting multiple tyrosine kinases that affect various pathways within the cell, with the ultimate goal of inhibition of cell proliferation. TKIs are oral agents, which is good for patient convenience, but also costly for patient finances, costing $5-8000 a month.

Question 27

Imatinib (Gleevec®) was first small molecule TKI available, used to treat ____and GIST by targeting the tyrosine kinase associated with the Bcr/Abl translocation in these diseases. The drug binds to the ATP-binding site of the p210 Bcr/Abl molecule, inhibiting substrate _________ and inducing _________. Imatinib also inhibits p185Bcr/Abl, platelet derived growth factor (PDGF), stem cell factor (SCF) and c-kit. Dasatinib and nilotinib bind to the active and inactive conformations of the _______ kinase domain, and also inhibits the ________family of kinases. Resistance to these drugs can occur through __________of the Bcr/Abl gene, point mutations and alterations in binding affinities. Major toxicities include (2), occurring in up to 50% of patients. __________may occur, including neutropenia, anemia and thrombocytopenia. Elevations in liver __________and __________ are usually transient, but dose adjustment may be warranted. ____________, consisting of decreased LVEF and congestive heart failure, has been reported with imatinib use and may be due to the drug’s affinity for the Abl protein in cardiac muscle, though this is unclear.

Answer 27

Imatinib (Gleevec®) was first small molecule TKI available, used to treat CML and GIST by targeting the tyrosine kinase associated with the Bcr/Abl translocation in these diseases. The drug binds to the ATP-binding site of the p210 Bcr/Abl molecule, inhibiting substrate phosphorylation and inducing apoptosis. Imatinib also inhibits p185Bcr/Abl, platelet derived growth factor (PDGF), stem cell factor (SCF) and c-kit. Dasatinib and nilotinib bind to the active and inactive conformations of the Bcr/Abl kinase domain, and also inhibits the SRC family of kinases. Resistance to these drugs can occur through amplification of the Bcr/Abl gene, point mutations and alterations in binding affinities. Major toxicities include (1) peripheral (periorbital) edema and (2) fluid retention, occurring in up to 50% of patients. Myelosuppression may occur, including neutropenia, anemia and thrombocytopenia. Elevations in liver transaminases and bilirubin are usually transient, but dose adjustment may be warranted. Cardiotoxicity, consisting of decreased LVEF and congestive heart failure, has been reported with imatinib use and may be due to the drug’s affinity for the Abl protein in cardiac muscle, though this is unclear.

Question 28

TKI's in renal cell carcinoma can lead to what type of toxicities

Answer 28

GI, liver and skin

Question 29

 The immunomodulatory actions of “imids” include inhibition of (2) and increased production of (2)   Other major immunomodulatory effects include _______ of adhesion molecules IL-5, IL-6, IL-8 and IL-12 and ______ of apoptosis, which combine to cause cell death.

Answer 29

 The immunomodulatory actions of “imids” include inhibition of (1) tumor necrosis factor-alpha (TNF-alpha), (2) nuclear factor kappa B (NF-kB), and increased production of (1) interleukin-2 (IL-2), IL-10, and (2) gamma interferon.   Other major immunomodulatory effects include down-regulation of adhesion molecules IL-5, IL-6, IL-8 and IL-12 and induction of apoptosis, which combine to cause cell death.

Question 30

Adverse events of imides: 1. neurotoxicity leading to 2. sensory symptoms such as (2) 3. SE which it is why it is recommended to take it at night- 4. sign of depression might be a sign of __________ 5. cardiovascular and in particular the risk of ____________events and thus patients should be placed on full _________ therapy for an INR of 2-3. 6. it also intercalates into guanine rich promoter regions of DNA having a __________ effect with absent and hypoplastic limbs

Answer 30

1. neurotoxicity leading to axonal damage 2. sensory symptoms such as distal paresthesias and hyperesthesias (stock and golve) 3. SE which it is why it is recommended to take it at night- sedation 4. sign of depression might be a sign of hypothyroidism 5. cardiovascular and in particular the risk of thromboembolic events and thus patients should be placed on full anticoagulant therapy for an INR of 2-3. 6. it also intercalates into guanine rich promoter regions of DNA having a teratogenic effect with absent and hypoplastic limbs

Question 31

hypomethylating agents are cell cycle specific agents with activity in ____-phase that incorporate into DNA, binding and depleting DNA ____________and lead to re-expression of epigenetically silenced genes

Answer 31

hypomethylating agents are cell cycle specific agents with activity in S-phase that incorporate into DNA, binding and depleting DNA methyltransferases and lead to re-expression of epigenetically silenced genes

Question 32

Hypermethylation leads to silencing of gene transcription, and hypermethylation in tumor cells will shut off important regulatory genes, such as

Answer 32

tumor suppressors

Question 33

Two hypomethylating drugs in this class are approved, azacytidine and decitabine, and are used to treat _________ and _____ Major toxicities associated with these agents include _____________, especially neutropenia, due to inhibition of DNA synthesis and early cytotoxic effects. Significant nausea and vomiting may also occur, requiring pre-medication with a _______ antagonist.

Answer 33

Two drugs in this class are approved, azacytidine and decitabine, and are used to treat myelodysplastic syndrome and leukemias. Major toxicities associated with these agents include myelosuppression, especially neutropenia, due to inhibition of DNA synthesis and early cytotoxic effects. Significant nausea and vomiting may also occur, requiring pre-medication with a serotonin antagonist.

Question 34

The proteasome is the major mechanism by which cells dispose of their

Answer 34

garbage (e.g. denatured proteins), via proteolytic degradation of molecules tagged for degradation by ubiquitination.

Question 35

Inhibition of the proteosome prevents proteolysis of ubiquinated proteins and disruption of normal intracellular protein metabolism Resulting in____________ Bortezomib, is the first proteasome inhibitor in use, and is currently used to treat (2) The major common toxicities of proteosome inhibitors are _______ (neutropenia and thrombocytopenia) and ____________neuropathies (stocking-glove distribution) . Other toxicities include nausea and vomiting, fatigue and malaise, and orthostatic hypotension.

Answer 35

in down-regulation of NF-kB which modulates transcription Bortezomib, is the first proteasome inhibitor in use, and is currently used to treat (1) multiple myeloma and (2) non-Hodgkin’s lymphoma. The major common toxicities of proteosome inhibitors are myelosuppression (neutropenia and thrombocytopenia) and peripheral sensory neuropathies (stocking-glove distribution). Other toxicities include nausea and vomiting, fatigue and malaise, and orthostatic hypotension.

Question 36

Immune checkpoint inhibitors manipulate the immune system by allowing_________ the receptors used for these agents are _______ and ______ they are being used in _________ types but there are multiple toxicities associated with them

Answer 36

Immune checkpoint inhibitors manipulate the immune system by allowing T cells to recognize cancer cells. the receptors used for these agents are PDL1 and CTLA4. they are being used in multiple tumor types but there are multiple toxicities associated with them

Question 37

MOA of ipilimumab

Answer 37

it binds to CTL4, which is a negative regulator of T cell activation, and blocks it interaction thus allowing T cell to proliferate and activate

Question 38

SE of ipilimumab are ___________ such as enterocolitis, hepatitis, dermatitis, neuropathies and pruritis but these can be treated with __________

Answer 38

SE of ipilimumab are immune related such as enterocolitis, hepatitis, dermatitis, neuropathies and pruritis but these can be treated with corticosteroids

Question 39

PD1 are used by cancer cell to

Answer 39

put a brake on the immune system

Question 40

Monoclonal that block PD1 allow the immune system to

Answer 40

recognize and kill tumor cells

Question 41

First 2 drugs to be approved for PD1 inhibitors are ___________and _________ but they lead to imune related side effects which can be treated with _________ and other SE includes increased _________

Answer 41

First 2 drugs to be approved are pembrolizumab and nivolumab but they lead to imune related side effects which can be treated with corticosteroids and other SE includes increased LFTs