Monoclonal Antibodies and their role in Pharmacology
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Transcript of Monoclonal Antibodies and their role in Pharmacology
MONOCLONAL ANTIBODIES AND THEIR ROLE IN PHARMACOLOGY
Dr.Harmanjit Singh PG Resident (pharmacology)GMC, Patiala
Monoclonal Antibodies
Monoclonal antibodies are Monospecific antibodies that are identical because they are produced by one type of immune cell that are all clones of a single parent cell.
Class of highly specific antibodies Produced by clone of single hybrid cells or
hybridomaFusing B lymphocytes with a tumour cell
The Structure of an Antibody
2 identical light chains (~220 amino acids long)
Variable domain: VL
Constant domain: CL
2 identical heavy chains (~440 amino acids long)
Variable domain: VH
3 Constant domains: CH1, CH2, CH3Covalent, disulfide bonds between cysteine residuesFlexible “hinge region”
Antibodies have two major functions: • Recognize and bind antigen • Induce immune responses after
binding
The variable region mediates binding• Affinity for a given antigen is
determined by the variable region• The variable region confers absolute
specificity for an antigen
The constant region mediates immune response after binding• Different classes of constant regions
generate different isotypes• Different isotypes of antibody have
differing properties
Antibody Function
Constant region
Variable region
History
1975 :Hybridoma Technology
George Kohler and Cesar Milstein devised a method to obtain large amounts of a mAb
1984 :
The Nobel Prize for Medicine
- In 1988, Greg Winter et al pioneered the techniques to humanize monoclonal antibodies
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Hybridoma production
Healthy B lymphocytes
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Fusion of mouse myeloma cells
Murine Mabs
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HGPRT – HYPOXANTHINE GUANINE PHOSPHORIBOSYL TRANFERASEHAT – HYPOXANTHINE, AMINOPTERIN, THYMIDINE
Transgenic mice
Transgenic mammalian cells (e.g. Chinese hamster ovary cells ) grown in culture are the industry standard for producing full-length mAb
Why should we be interested ?The outlook for monoclonal antibody therapeutics is
healthy
mAbs drive the development of multibillion dollar biotechnology industry.
US$26 billion by the end of the decade.
Quicker and less costly development higher success rates premium pricing and potentially reduced threat from generics
100 mAb were Expected By 2010
Origin
First generation
Murine, rabbit or rat proteins purified
after immunisation with antigen
Abs to these proteins (Ag) generated in
patients human antimouse antibody
(HAMA)
Block effectiveness of therapy
Adverse events serum sickness or anaphylaxis
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Origin
Second generation
DNA technology or genetic engineering
used to construct hybrids composed of
human Abs regions with murine
Chimeric Abs
Humanized
Human
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EVOLUTION OF MONOCLONAL ANTIBODY
1. TRANSGENIC
2. LIBRARIES
a.BACTERIOPHAGE
b. mRNA
c. Cell Surface
Ist generation mab
2nd generation mab
daclizumab
Types of mAbs
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Purple denotes human component orange murine component
Murine
Derived from mice
Patients treated with murine mAbs develop
a human antimouse antibody (HAMA)
response
Rapid clearance of the mAb
Poor tumour penetration
Hypersensitivity reactions
90Y-ibritumomab 131I -Tositumomab
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Chimeric Abs
Antigen binding parts (variable region) of
mouse
Ab with effector parts (constant region) of
human
Infliximab
Abciximab
Rituximab15
Humanized
Human Ab with complimentary determining
region
(CDR) or hypervariable region from non
human source
Daclizumab
Trastuzumab
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Human Abs
Recombinant DNA technology:
Genes for variable Fab portion of human Abs
is inserted in genome of bacteriophages &
replicated
Mixed with Ag & complementary Ab
producing
phages selected
e.g. Adalimumab
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Nomenclature of Monoclonal AntibodiesPrefix Target Source Suffix
variable
-o(s)- bone -u- human
-mab
-vi(r)- viral -o- mouse
-ba(c)- bacterial -a- rat
-li(m)- immune -e- hamster
-le(s)- infectious lesions -i- primate
-ci(r)- cardiovascular -xi- chimeric
-mu(l)- musculoskeletal -zu- humanized
-ki(n)- interleukin -axo- rat/murine hybrid
-co(l)- colonic tumor
-me(l)- melanoma
-ma(r)- mammary tumor
-go(t)- testicular tumor
-go(v)- ovarian tumor
-pr(o)- prostate tumor
-tu(m)- miscellaneous tumor
-neu(r)- nervous system
-tox(a)- toxin as target
Nomenclature
Suffix
Human: -umab
Humanized: -zumab
Murine: -momab
Chimeric: -ximab
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Examples ab- + -ci- + -xi- + -mab:
chimeric monoclonal antibody used on the cardiovascular system.
tras- + -tu- + -zu- + -mab: humanized monoclonal antibody used against a tumor.
Pali- + -vi- + -zu- + -mab humanized mab used against a
virus (RSV)
Pharmacokinetics: mAbs
Routes of administration: Subcutaneously (Rituximab, Trastuzumab,
Adalimumab) Intramuscularly (Palivizumab) Intravenously
IV route: preferred because of 100% bioavailability
Route for elimination of antibodies Via uptake & catabolism by reticuloendothelial
system & target tissue.21
P/K: mAbs
Half-life Chimeric : 4 –15 daysHumanized: 3 - 24 daysRecombinant human: 11– 24 days
Human antimouse antibody (HAMA) response develops 7–10 days following exposure to murine antibody
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List of some important Mabs
Therapeutic agent Indication
Alemtuzumab B cell CLL
Bevacizumab Met. Colon cancer
Ranibizumab Neovas. Macular degenration
Cetuximab Met. Colon cancer
Gemtuzumab AML
Panitumumab Colorectal cancer
Rituximab Low grade NHL
Trastuzumab Met. Breast cancer
Therapeutic agent Indication
Abatacept Severe RA
Basiliximab, Renal, heart transplant
Daclizumab Renal transplant, M.Sclerosis
Efalizumab Psoriasis
Adalimumab RA
Abciximab ACS
Omalizumab Allergic asthma
Palivizumab RSV infection
Natalizumab M.Sclerosis
Therapeutic uses
Immunosuppression
Autoimmune diseases
Malignancies
Antiplatelet therapy
Infectious diseases
Asthma
Osteoporosis
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1.Immunosuppression
Muromonab CD-3: Murine mAb
1st mAb approved for clinical use in humans
Act on CD3 receptors
Apoptosis of the T cells
Prevents graft rejection in renal transplant
ADRs: skin reactions, fatigue,
fever, chills, myalgia, headaches, nausea &
diarrhea 26
Autoimmune diseases
• Therapeutic uses of Infliximab: • Blocks TNF-α
Crohn’s disease & Ulcerative colitisRA & ASPsoriatic arthritis
• ADR- Reactivation of TB, Hepatitis BLeukopenia, Neutropenia,
Thrombocytopenia & Pancytopenia
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Autoimmune diseases
Epratuzumab:
Humanized Ab
Binds to the glycoprotein CD 22 of mature
and malignant B-cells
Therapeutic use:
NHL
SLE
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Autoimmune diseasesEfalizumab: Humanized Ab MoA
binds wth CD11, a subunit of lymphocyte function-associated antigen 1
Therapeutic uses Plaque psoriasisADRsBacterial sepsis, viral meningitis, invasive
fungal disease and progressive multifocal leukoencephalopathy (PML)
Withdrawn from market 29
2.MalignanciesRituximab:
• First chimeric IgG-I mAb
• MoA:
Directed against CD 20 on B cells
• P/K
Bioavailability: 100% (IV)
Half life: 30 to 40 hours
Excretion: Phagocytosis and catabolism in RES30
Malignancies
• Therapeutic uses of Rituximab:
Non hodgkins lymphoma
Multiple myeloma
ADRs:
Severe infusion reactions
Cardiac arrest
Tumor lysis syndrome
31
MalignanciesAlemtuzumab Humanized IgG1 MoA:
Binds to CD52 B & T cells Therapeutic uses
Chronic lymphocytic leukemia (CLL) in failed fludarabine therapy
Cutaneous T-cell lymphoma(CTCL)
ADRs: Hypotension, rigors, fever, shortness of breath, bronchospasm, chills, Lymphopenia, Anaemia, Thrombocytopenia
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Malignancies
Cetuximab
Chimeric Ab
Directed against EGFR
Inhibits tumor growth
Therapeutic use
Metastatic colorectal cancer (EGFR over
expressive)
Head and neck cancer
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Malignancies
ADRs of Cetuximab:
Acne-like rash
Fevers, chills, rigors, urticaria, pruritis,
rash, hypotension, bronchospasm,
dyspnea, wheezing, angioedema,
dizziness, anaphylaxis
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Malignancies
Trastuzumab
• Humanized Ab
• MoA: Binds to HER-2/neu,
Downregulation of receptor
• Therapeutic use Metastatic breast ca (over express
HER-2/neu)
ADR : Cardiomyopathy35
Malignancies
BevacizumabBevacizumab Humanized mAb MoA:
Directed against VEGF• Blocks VEGF in neovascularisation• Therapeutic uses
Metastatic colorectal ca, Pancreatic ca, Breast ca
Prostate ca
ADRsRisk of bleeding, Bowel perforation, Nasal
septum perforation36
3.Antiplatelet therapyAbciximab
Chimeric mAb MoA
Glycoprotein IIb/ IIIa receptor antagonistPrevents platelet aggregation Inhibits fibrinogen, von Willebrand factor
Therapeutic usesAcute coronary syndromePCI
ADRs: ↑ risk of bleeding, Thrombocytopenia
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5.AsthmaOmalizumab Humanized Ab MoA
Binds IgE # interaction with basophils & mast cells
Therapeutic use B. Asthma in adults & adolescents
refractory to inhaled corticosteroid therapy
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Osteoporosis Denosumab - Human mab - Act against RANK Ligand - Approved by FDA for use in
postmenopausal women with risk of osteoporos
- ADRs UTI and RTI Cataract , constipation, rashes and
joint pain
Future aspects Zanolimumab
CD4 specific mAb Cutaneous T cell lymphoma Phase III clinical trial
Daclizumab: Humanized mAb (Phase II
clinical trials )
Binds to IL – 2
Therapeutic use : Prophylaxis of acute organ
rejection in renal transplant
Multiple Sclerosis 40
Future aspects
Ipilimumab Human monoclonal antibody Undergoing clinical trials treatment
of melanoma
Tremelimumab Human IgG2 monoclonal antibody Phase III clinical trial for
advanced melanoma
Ruplizumab Humanized monoclonal antibody Systemic lupus erythematosus Lupus nephritis 41
Future aspects Efungumab : for Invasive Candida Infection Panobacumab : for Pseudomonas Infection Solanezumab : for Alzheimer’s Disease Natalizumab : for Multiple Sclerosis
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OTHER USES IMAGING : Arcitumomab : colorectal carcinoma Nofetumomab : small cell lung cancer DIAGNOSTICS : HIV Diagnostic kit A monoclonal antibody can be used to
detect pregnancy only 14 days after conception.
Other monoclonal antibodies allow rapid diagnosis of hepatitis, influenza, herpes, streptococcal, and Chlamydia infections.
Ethical issues: Freund’s complete adjuvant (FCA) (to enhance the immune
response): painful lesions at the injection site. Pristane as a "priming" agent - granulomatous
reactions Respiratory distress: due to ascites. Shock - rapid fluid loss. FCA and pristane should not be used where it is
possible to use no adjuvant or less irritant adjuvants. FCA should not be used more than once in individual
mice. The volume of FCA and pristane used should not
exceed 0.1ml and 0.2ml respectively. Individual mice should not be inoculated with
adjuvant more than 3 times. A priming agent should not be used in individual
mice more than once. Ascites fluid should only be harvested once at the
time of euthanasia.
TO SUMMARISE : MAbs are highly specific Abs produced by
a clone of single hybrid cells formed by fusion of B cell with the tumor cell.
The hybridoma formed yields higher amount of MAbs.
MAbs can be produced in vitro and in vivo . Animals are utilized to produce MAbs, but
these antibodies are associated with immunogenicity and ethical problems.
Recombinant DNA technology, genetic engineering and transgenic animals are used to produce humanized MAbs or pure human MAbs, with fewer ADRs
Used for treatment of cancer, autoimmune disorders, graft rejections, infections, asthma etc.
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