Monoclonal antibodies are man-made versions of antibodies that are identical because they were produced by one type of immune cell. They can be designed to attack very specific parts of cancer cells. The main types used in cancer immunotherapy are naked monoclonal antibodies, conjugated monoclonal antibodies (attached to chemotherapy drugs or radioactive particles), and bispecific monoclonal antibodies (attached to two different antigens). Immunotherapy treatments that target immune checkpoint proteins like PD-1, PD-L1, and CTLA-4 have also shown promise in treating cancers. Non-specific immunotherapies like cytokines can generally stimulate the immune system to potentially help it better attack cancer cells.

1. MONOCLONAL ANTIBODIES
BY
DR.AYUSH GARG
PG JR1

2. Cancer Immunotherapy
• Immunotherapy is treatment that uses certain parts of a person’s
immune system to fight diseases such as cancer. This can be done in a
couple of ways:
1. Stimulating your own immune system to work harder or smarter to
attack cancer cells
2. Giving you immune system components, such as man-made
immune system proteins

3. Types of cancer immunotherapy
• The main types of immunotherapy now being used to treat cancer
include:
Monoclonal antibodies: These are man-made versions of immune
system proteins.
• Antibodies can be very useful in treating cancer because they can be
designed to
• attack a very specific part of a cancer cell.
Immune checkpoint inhibitors: These drugs basically take the
‘brakes’ off the
• immune system, which helps it recognize and attack cancer cells.

4. Cancer vaccines: Vaccines are substances put into the body to start
an immune
• response against certain diseases. We usually think of them as being
given to healthy
• people to help prevent infections. But some vaccines can help
prevent or treat cancer.
Other, non-specific immunotherapies: These treatments boost the
immune system
• in a general way, but this can still help the immune system attack
cancer cells.

5. What are antibodies?
An antibody is a protein used by the immune system to identify and
neutralize foreign objects like bacteria and viruses. Each antibody
recognizes a specific antigen unique to its target.
Monoclonal antibodies (mAb) are antibodies that are identical
because they were produced by one type of immune cell, all clones of
a single parent cell.
Polyclonal antibodies are antibodies that are derived from different
cell lines.

6. Isotypes
According to differences in their heavy chain constant domains, immunoglobulins are
grouped into five classes, or isotypes: IgG, IgA, IgM, IgD, and IgE.
IgG: IgG1 (66%), IgG2 (23%), IgG3 (7%) and IgG4 (4%) , blood and tissue liquid.
IgA:IgA1 (90%) and IgA2 (10%), stomach and intestines
IgM: normally pentamer, ocassionally hexamer, multiple immunoglobins linked with
disulfide bonds
IgD:1% of proteins in the plasma membranes of B-lymphocytes, function unknown
IgE: on the surface of plasma membrane of mast cells, play a role in immediate
hypersensitive and denfensive for parasite

7. The structure of antibodies

8. History of Mab development
• 1890 Von Behring and kitasato discovered the serum of vaccinated persons contained certain
substances, termed antibodies
• 1900 Ehrlich proposed the “ side-chain theory”
• 1955 Jerne postulated natural selection theory. Frank Macfarlane Burnet expended.
• Almost the same time, Porter isolated fragment of antigen binding (Fab) and fragment
crystalline (Fc) from rabbit y-globulin.
• 1964 Littlefield developed a way to isolate hybrid cells from 2 parent cell lines using the
hypoxanthine-aminopterin-thymidine (HAT) selection media.
• 1975 Kohler and Milstein provided the most outstanding proof of the clonal selection theory
by fusion of normal and malignant cells
• 1990 Milstein produced the first monoclonal antibodies.

9. Monoclonal antibodies to treat cancer
• The immune system attacks foreign substances in the body is by making large
numbers of antibodies.
• An antibody is a protein that sticks to a specific protein called an antigen.
• Antibodies circulate throughout the body until they find and attach to the
antigen.
• Once attached, they can recruit other parts of the immune system to destroy the
cells containing the antigen

11. VEGF PDGF
HGF
NRPs
Eph
TGFβ bFGF
Ang
Endothelial cell &
Pericyte
BRAF
MEK
ERK
RAS
PI3K
AKT
mTor
Tumor

13. Types of MoAbs
Structure % Human Example Comments
Mouse 0 Tositumomab,
Ibritumomab
Radio-
conjugates
Chimeric 65 Cetuximab,
Rituximab
Humanized 95 Trastuzumab
Human 100 Panitumumab Transgenic mice

14. The types of mAb designed
A.Murin source mAbs: rodent mAbs with excellent affinities and specificities,
generated using conventional hydrioma technology. Clinical efficacy
compromised by HAMA(human anti murine antibody) response, which lead to
allergic or immune complex herpersensitivities.
B.Chimeric mAbs: chimers combine the human constant regions with the intact
rodent variable regions. Affinity and specificity unchanged. Also cause human
antichimeric antibody response (30% murine resource)
C.Humanized mAbs: contained only the CDRs of the rodent variable region grafted
onto human variable region framework

15. Nomenclature of MoAbs
• Last syllable is always –mab
• Next to last syllable
 -u- human (100%) : Panitumumab
 -zu- humanized (95%) : Trastuzumab
 -xi- chimeric (65%) : Rituximab
 -o- mouse, -a- rat, -e- hamster, -i- primate : Tositumomab
• Previous syllable
• -tu(m)- for tumor in general [-ma(r)- breast, -pr(o)- prostate, -co(l)- colon, etc.]
• -ci(r)- for circulatory : Bevacizumab

16. FDA-Approved “Naked” (Non-Conjugated)
MoAbs
Generic Name Brand Name Target Cancer(s)
Alemtuzumab Campath CD52 CLL
Bevacizumab Avastin VEGF Multiple
Cetuximab Erbitux EGFR1 Colon, H&N
Panitumumab Vectibix EGFR1 Colon
Rituximab Rituxan CD20 Lymphomas
Trastuzumab Herceptin HER-2 Breast

18. Types of monoclonal antibodies
• Naked monoclonal antibodies
• Naked mAbs are antibodies that work by themselves. There is no drug or
radioactive material attached to them. These are the most common type of mAbs
used to treat cancer.
• Most naked mAbs attach to antigens on cancer cells, but some work by binding to
antigens on other, non-cancerous cells, or even free-floating proteins

19. Naked mAbs can work in different ways.
• Some boost a person’s immune response against cancer cells by
attaching to them and acting as a marker for the body’s immune
system to destroy them. An example is-
• Alemtuzumab which is used to treat some patients with chronic
lymphocytic leukemia (CLL). Alemtuzumab binds to the CD52 antigen,
which is found on cells called lymphocytes (which include the
leukemia cells). Once attached,the antibody attracts immune cells to
destroy these cells.
• Some naked mAbs boost the immune response by targeting immune
system checkpoints.

20. • Other naked mAbs work mainly by attaching to and blocking antigens on cancer
cells (or other nearby cells) that help cancer cells grow or spread. For example,
• Trastuzumab is an antibody against the HER2 protein. Breast and stomach cancer
cells sometimes have large amounts of this protein on their surface.
• When HER2 is activated, it helps these cells grow. Trastuzumab binds to these
proteins and stops them from becoming active.

21. Conjugated monoclonal antibodies
• Monoclonal antibodies (mAbs) joined to a chemotherapy drug or to a radioactive
particle are called conjugated monoclonal antibodies.
• The mAb is used as a homing device to take one of these substances directly to
the cancer cells. The mAb circulates throughout the body until it can find and
hook onto the target antigen.
• It then delivers the toxic substance where it is needed most. This lessens the
damage to normal cells in other parts of the body.
• Conjugated mAbs are also sometimes referred to as tagged, labeled, or loaded
antibodies.

22. Radiolabeled antibodies
• Radiolabeled antibodies have small radioactive particles attached to them.
•
• Ibritumomab tiuxetan is an example of a radiolabeled mAb. This is an antibody
against the CD20 antigen, which is found on lymphocytes called B cells.
• The antibody delivers radioactivity directly to cancerous B cells and can be used
to treat some types of non-Hodgkin lymphoma.
• Treatment with this type of antibody is sometimes known as
radioimmunotherapy (RIT).

23. Chemolabeled antibodies
• These mAbs have powerful chemotherapy (or other) drugs attached to them.
They are also known as antibody-drug conjugates (ADCs). (The drug is often too
powerful to be used on its own – it would cause too many side effects if not
attached to an antibody.)
• Chemolabeled antibodies used to treat cancer include:
• Brentuximab vedotin an antibody that targets the CD30 antigen (found on
lymphocytes), attached to a chemo drug called MMAE. This drug is used to treat
Hodgkin lymphoma and anaplastic large cell lymphoma.
• Ado-trastuzumab emtansine (also called TDM-1), an antibody that targets the
HER2 protein, attached to a chemo drug called DM1. It’s used to treat some
breast cancer patients whose cancer cells have too much HER2.

24. • A related drug known as denileukin diftitox is an immune system protein
known as interleukin-2 (IL-2) attached to a toxin from the germ that causes
diphtheria.
• Although it’s not an antibody, IL-2 normally attaches to certain cells in the
body that contain the CD25 antigen, which makes it useful for delivering
the toxin to these cells.
• Denileukin diftitox is used to treat lymphoma of the skin (also known as
cutaneous T-cell lymphoma). It’s also being studied for use against a
number of other cancers.

25. Bispecific monoclonal antibodies
• These drugs are made up of parts of 2 different mAbs, meaning they can
attach to 2 different proteins at the same time.
• An example is blinatumomab , which is used to treat some types of acute
lymphocytic leukemia (ALL).
• One part of blinatumomab attaches to the CD19 protein, which is found on
some leukemia and lymphoma cells.
• Another part attaches to CD3, a protein found on immune cells called T
cells.
• By binding to both of these proteins, this drug brings the cancer cells and
immune cells together, which is thought to cause the immune system to
attack the cancer cells.

26. Common Side effects of mAb
• Fever
• Chills
• Weakness
• Headache
• Nausea
• Vomiting
• Diarrhea
• Low blood pressure
• Rashes

27. • Some mAbs can have side effects that are related to the antigens they
target. For example:
1. Bevacizumab is an mAb that targets a protein called VEGF that affects
tumor blood vessel growth. It can cause side effects such as high
blood pressure, bleeding, poor wound healing, blood clots, and kidney
damage.
2. Cetuximab is an antibody that targets a cell protein called EGFR, which
is found on normal skin cells (as well as some types of cancer cells).
This drug can cause serious rashes in some people.

28. Immune checkpoint inhibitors to treat cancer
• An important part of the immune system is its ability to tell between normal cells in the
• body and those it sees as “foreign.” This lets the immune system attack the foreign cells
• while leaving the normal cells alone. To do this, it uses “checkpoints” – molecules on
• certain immune cells that need to be activated (or inactivated) to start an immune
• response.
• Cancer cells sometimes find ways to use these checkpoints to avoid being attacked by
the
• immune system. But drugs that target these checkpoints hold a lot of promise as cancer
• treatments.

29. Treatments that target PD-1 or PD-L1
• PD-1 is a checkpoint protein on immune cells called T cells. It
normally acts as a type of
• “off switch” that helps keep the T cells from attacking other cells in
the body. It does this
• when it attaches to PD-L1, a protein on some normal (and cancer)
cells. When PD-1
• binds to PD-L1, it basically tells the T cell to leave the other cell alone.
Some cancer cells
• have large amounts of PD-L1, which helps them evade immune
attack.

30. • Monoclonal antibody treatments that target either PD-1 or PD-L1 can boost the immune
• response against cancer cells and have shown a great deal of promise in treating certain
• cancers. Examples of treatments that target PD-1 include:
• · Pembrolizumab (Keytruda®)
• · Nivolumab (Opdivo®)
• These have been shown to be helpful in treating melanoma of the skin, with some
people
• having long-lasting responses to treatment. These treatments have also been shown to
be
• helpful against non-small cell lung cancer in large studies. Smaller studies have shown
• promising early results against some other cancers as well, including kidney and
• colorectal cancer.

31. Treatments that target CTLA-4
• CTLA-4 is another protein on some T cells that acts as a type of “off switch” to keep the
• immune system in check.
• Ipilimumab (Yervoy®) is a monoclonal antibody that attaches to CTLA-4 and stops it
• from working. This can boost the body’s immune response against cancer cells.
• This drug is used to treat melanoma of the skin. It is also being studied for use against
• other cancers.
• Because ipilimumab affects the immune system, it can sometimes cause serious or even
• life-threatening side effects. In fact, compared to drugs that target PD-1 or PD-L1, serious
• side effects seem to be more likely with ipilimumab.

32. Non-specific cancer immunotherapies and
adjuvants
• Non-specific immunotherapies don’t target cancer cells specifically.
They stimulate the immune system in a more general way, but this
can still sometimes lead to a better immune response against cancer
cells.
• Some non-specific immunotherapies are given by themselves as
cancer treatments.
• Others are used as adjuvants (along with a main treatment) to boost
the immune system to improve how well another type of
immunotherapy (such as a vaccine) works.
• Some are used by themselves against some cancers and as adjuvants
against others.

33. Cytokines
• Cytokines are chemicals made by some immune system cells. They
are crucial in
• controlling the growth and activity of other immune system cells and
blood cells
• Cytokines are injected, either under the skin, into a muscle, or into a
vein. The most
• common ones are discussed here.

34. Interlukins
• Interleukins are a group of cytokines that act as chemical signals between white blood
• cells.
• Interleukin-2 (IL-2) helps immune system cells grow and divide more quickly. A
manmade
• version of IL-2 is approved to treat advanced kidney cancer and metastatic
• melanoma.
• IL-2 can be used as a single drug treatment for these cancers, or it can be combined with
• chemotherapy or with other cytokines such as interferon-alfa. Using IL-2 with these
• treatments might help make them more effective against some cancers, but the side
• effects of the combined treatment are also increased.

35. • Side effects of IL-2 can include flu-like symptoms such as chills, fever, fatigue, and
• confusion. Most people gain weight. Some have nausea, vomiting, or diarrhea.
Many
• people develop low blood pressure, which can be treated with other medicines.
Rare but
• potentially serious side effects include an abnormal heartbeat, chest pain, and
other heart
• problems. Because of these possible side effects, if IL-2 is given in high doses, it
must be
• done in a hospital.
• Other interleukins, such as IL-7, IL-12, and IL-21, are now being studied for use
against
• cancer too, both as adjuvants and as stand-alone agents.

36. Interferons
• Interferons are chemicals that help the body resist virus infections and
cancers. The types
• of interferon (IFN) are named after the first 3 letters of the Greek alphabet:
• · IFN-alfa
• · IFN-beta
• · IFN-gamma
• Only IFN-alfa is used to treat cancer. It boosts the ability of certain immune
cells to
• attack cancer cells. It may also slow the growth of cancer cells directly, as
well as the
• blood vessels that tumors need to grow.

37. • IFN-alfa can be used to treat these cancers:
• · Hairy cell leukemia
• · Chronic myelogenous leukemia (CML)
• · Follicular non-Hodgkin lymphoma
• · Cutaneous (skin) T-cell lymphoma
• · Kidney cancer
• · Melanoma
• · Kaposi sarcoma

38. • Side effects of interferons can include:
• · Flu-like symptoms (chills, fever, headache, fatigue, loss of appetite,
nausea,
• vomiting)
• · Low white blood cell counts (which increase the risk of infection)
• · Skin rashes
• · Thinning hair

39. Alemtuzumab
• Indication
Campathis indicated
for the treatment of
patients with chronic
lymphocytic leukemia
(CLL) who have been
treated with alkylating
agents and who have
failed fludarabine
therapy.
• Humanized monoclonal
antibody directed
against CD52 antigen
• Expressed on B & T
lymphocytes
• Not expressed on bone
marrow progenitor cells

40. 40
Mechanism of Action
• Lyses lymphocytes via
• Complement fixation
• Antibody dependent cell
mediated cytotoxicity
• Induction of apoptosis
• Different mechanism of action
from available cytotoxic
chemotherapeutic agents
CD52
Effector cell
FC
Receptor
Campath
Complement
Leukemia
Cell

41. Day 1 - 3 mg Campath
30 mg Campath
3x/week schedule
e.g. Monday, Wednesday, Friday
I.V. Administration
Day 2 - 10 mg Campath
Day 3 - 30 mg Campath
Duration of Treatment 4-12 Weeks Based on Response

42. Trastuzumab
• Monoclonal antibody against epidermal growth factor receptor 2
(EGFR2, HER-2)
• Very effective against breast cancers in which HER-2 is “over-
expressed” (more than usual amount per cell) (about 20% of all
breast cancers)
• Often used in combination with chemotherapy

43. Trastuzumab: Mechanism of
Action

44. 1. Trastuzumab mediates ADCC
Once bound to theFc domain of trastuzumab, the NK
cells release substances…
…that perforate the tumour cell membraneand
promote cell death
NahtaR, EstevaFJ. BreastCancerRes2006;8:215
ClynesRA, et al. Nat Med2000;6: 443-446
GennariR, et al. ClinCancerRes2004;10: 5650-5655
ArnouldL, et al. Br J Cancer2006;94:259-267

45. 2. Trastuzumab prevents
formation of p95HER2
Formationofthe activep95fragment,
throughproteolyticcleavageofthe
extracellulardomainofHER2…
…is prevented bytrastuzumab
MolinaMA, et al. CancerRes2001;61:4744-4749
NahtaR, Esteva FJ. CancerLett 2006;232:123-138

46. 3. Trastuzumab blocks
HER2-activated cell proliferation
Trastuzumabinterrupts
thisprocess
HER2signalling induces
cell proliferation
NahtaR, Esteva FJ. CancerLett 2006;232:123-138
FryMJ. BreastCancerRes2001;3: 304-312
GershteinES, et al. ClinChim Acta 1999;287:59-67
Yakes FM, et al. CancerRes2002;62: 4132-4141
Longva KE, et al. Int J Cancer 2005;116: 359-367

47. 4. Trastuzumab inhibits
HER2-regulated angiogenesis
Trastuzumabinhibits this process
HER2signalling induces angiogenesis
IzumiY, et al. Nature 2002;416: 279-280
NahtaR, Esteva FJ. CancerLett 2006;232:123-138
WenXF, et al. Oncogene2006;25:6986-6996
KlosKS, et al. Cancer2003;98:1377-1385

48. Trastuzumab: 1 target
4 mechanisms of action
Prevention of formation of p95HER2
Inhibitionof cell proliferation
Activation of ADCC
Inhibitionof
HER2-regulatedangiogenesis

49. HER2
HerceptinTumour
cell
+
ADCC is a key mechanism of Herceptin’s antitumour
activity in vivo
ADCC
FcgRIII
NK cell
• OnceboundtoHER2,the Herceptin Fc domainrecruitsimmune cells totargetanddestroythe
tumour

51. Cetuximab
• Monoclonal antibody against epidermal growth factor receptor 1
(EGFR1)
• Effective in colon cancer and head and neck cancer; possibly useful in
lung cancer
• Used with chemotherapy and with radiation therapy

52.  IgG1 MAb (chimerized)
 Binds specifically to EGFR
and its heterodimers
 Binds to EGFR with high affinity
(Kd = 2.0 x 10–10 M): 1 log higher
than the natural ligand
 Following the recommended dose
regimen (400 mg/m2 initial dose/250 mg/m2
weekly dose), the mean half-life was 114 hours
(range 75-188 hours)
 Competitively inhibits ligand binding to EGFR
 Stimulates receptor internalization
 Blocks receptor dimerization, tyrosine kinase phosphorylation,
and signal transduction

53. Bevacizumab
• Monoclonal antibody against vascular endothelial growth factor (VEGF), which
stimulates angiogenesis (growth of new blood vessels into tumor)
• Deprives tumors of the blood supply they need for growth and invasion
• Effective against cancers of colon, lung, breast, kidney, and brain
• Bevacizumab in combination with paclitaxel is indicated for the treatment of
patients who have not received chemotherapy for their locally recurrent or
metastatic HER2-negative breast cancer.

54. Rituximab: a mouse/ human chimeric anti-
CD20 monoclonal antibody
Murine variable regions
bind specifically to CD20 on normal/ malignant
B-cells
Human K constant regions
Human IgG1 Fc domain
• interacts with human effector mechanisms
(ADCC, CDC)
• low immunogenicity

55. CD20 Expression in B-Cell Development
Plasma cell
Pluripotent stem
cell
Lymphoid stem
cell
Pre-B cell B cell Activated B cell
Bone marrow Blood, lymph
CD 20

56. Mechanism Of Action
Malignant B-cell
Complement
CD20
CD20
Direct
induction of
apoptosis
Killer
Leukocyte

57. Side Effects
• Mild and transient, mainly during first infusion
• Fever, chills ( prevention)
• Temporary drop in blood pressure, dyspnea
• Rare: antibodies against rituximab

58. Monoclonal Antibodies In Development
• Epratuzumab ch806
• Matuzumab CP-751,871
• Nimotuzumab IMC-A12
• Zalutumumab VEGF-Trap
• Pertuzumab IMC-18F1
• Mapatumumab IMC-1121B
• Lexatumumab IMC-3G3
• Volociximab Vitaxin
• Pemtumomab CNTO 95
• Labetuzumab