MONOCLONAL ANTIBODIES

RESIDENT: Fariha Fatima

MODERATOR: Dr. Mohammad

Tariq Salman

ANTIBODIES

Derived from different B

Lymphocytes cell lines

POLYCLONAL. MONOCLONAL.

Derived from a single B cell

clone

Batch to Batch variation

affecting Ab reactivity &

titre

mAb offer Reproducible,

Predictable & Potentially

inexhaustible supply of Ab

with exquisite specificity

Enable the development of

secure immunoassay systems.

NOT Powerful tools for

clinical diagnostic tests

4

The idea of a "magic bullet"

was first proposed by Paul

Ehrlich who at the beginning

of the 20th century postulated

that if a compound could be

made to selectively target a

disease-causing organism, then

a toxin for that organism could

be delivered along with the

agent of selectivity.

Discovery

5

CLASSIFICATION OF MONOCLONAL ANTIBODIES:

I. First generation monoclonal antibodies

II. Second generation monoclonal antibodies

NOMENCLATURE

Georges Köhler César Milstein, and Niels Kaj Jerne in 1975 who shared the Nobel Prize in Physiology or Medicine in 1984 for the discovery hybridomatechnology

14

Large scale production of Mabs:

It involves establishing the hybridoma cell bank with cells that

are free of adventitious agents such as viruses and mycoplasma

that have stability in continuous culture for antibody production

rate and cell viability and do not have unusual or expensive

media requirements.

Cell ,cell debris ,lipids,

clotted materials are first

removed by

Charged impurities such

nucleic acids and endotoxins

separated by

Antibody Type Target Indication

Abciximab Chimeric Inhibition of glycoprotein

IIb /III a

Cardiovascular disease

Basiliximab Chimeric IL 2Rα receptor(CD25) Transplant rejection

Cetuximab Chimeric Epidermal growth factor

receptor

Colorectal cancer,head

and neck cancer

Infliximab Chimeric Inhibition of TNF α

signalling

Several autoimmune

disorders

Rituximab Chimeric CD20 Non Hodgkin’s

lymphoma

Ibritumomab tiuxetan Murine CD20 Non Hodgkin’s

lymphoma

Muromonab-CD3 Murine T cell CD3 receptor Transplant rejection

FDA APPROVED THERAPEUTIC MONOCLONAL ANTIBODIES

Antibody Type Target Indication

Tositumomab Murine CD20 Non Hodgkin’s

lymphoma

Alemtuzumab Humanized CD52 Chronic lymphocytic

leukemia

Bevacizumab Humanized Vascular endothelial

growth factor(VEGF)

Colorectal cancer, age

related macular

degeneration

Certolizumab pegol Humanized Inhibition of TNF-α

signalling

Crohn’s disease

Daclizumab Humanized IL-2Rα receptor(CD25) Transplant rejection

Eculizumab Humanized Complement system

protein C5

Paroxysmal nocturnal

hemoglobinuria

Efalizumab Humanized CD11a Psoriasis

Antibody Type Target Indication

Gemtuzumab Humanized CD33 Acute myelogenous

leukemia

Natalizumab Humanized α-4 integrin Multiple sclerosis , crohn’s

disease

Omalizumab Humanized IG-E Mainly allergy related

asthma

Palivizumab Humanized An epitope of RSVF

protein

Respiratory syncytial virus

Ranibizumab Humanized VEGF-A Macular degeneration

Trastuzumab Humanized ErbB2 Breast cancer

Antibody Type Target Indication

Adalimumab Human Inhibition of TNF-α

signalling

Several autoimmune

disorders

Panitumumab Human Epidermal growth factor

receptor

Colorectal cancer

Drug (brand name) Sponsor Properties Indications

Ramucirumab (Cyramza) Eli Lilly VEGFR2 antagonist Gastric cancer

Siltuximab (Sylvant) Janssen Biotech IL-6-specific antibodyMulticentric Castleman's

disease

Vedolizumab (Entyvio) TakedaIntegrin-receptor

antagonist

Ulcerative colitis and

Crohn's disease

Pembrolizumab

(Keytruda)Merck & Co. PD1-specific antibody Metastatic melanoma

Blinatumomab (Blincyto) AmgenCD19- and CD3-bispecific

antibodyB-ALL

Nivolumab (Opdivo) Bristol-Myers Squibb PD1 inhibitorUnresectable or

metastatic melanoma

2014 FDA drug approvals

SELECTED LATE-STAGE DRUGS TO WATCH IN 2015

Drug name Sponsors Properties Indication Event due in 2015

Secukinumab NovartisIL-17-specific

antibodyPsoriasis

PDUFA decision in

January

Evolocumab AmgenPCSK9-specific

antibody

Hypercholesterolae

mia

PDUFA decision by

September

Alirocumab Sanofi/RegeneronPCSK9-specific

antibody

Hypercholesterolae

miaPDUFA decision

Ocrelizumab RocheCD20-specific

antibodyMultiple sclerosis

Top-line Phase III

data

TYPES OF MABS THAT ARE USED IN TREATMENT:

Naked MAbs:

These are without any drug or radioactive material

attached to them.

They attach themselves to specific Ag on cells, eg.

Cancer cells.

1. Trastuzumab :for advanced breast cancer

2. Rituximab : for B cell non-Hodgkin’s lymphoma

3. Cituximab :for advanced colorectal cancer

4. Bevacizumab :for metastatic colorectal cancer

5. Alemtuzumab :for B cell chronic lymphocytic leukemia

Conjugated Mabs:

They can be used to deliver radionuclides , toxins or

cytotoxic drugs to a specific tissue or malignant cell

population.

These are attached to drugs, toxins or radioactive atoms.

They are also referred to “tagged” “labelled” or “loaded”

antibodies.

1. Ibritumomab tiuxetin: radiolabelled Mab to treat B cell

non-Hodgkin’s lymphoma.

2. Tositumomab : radiolabelled Mab for non-Hodgkin’s

lymphoma

3. Gemtuzumab ozogamicin (Mylotarg): immunotoxin Mab

for AML

o Blocking or steric hindrance of the function of target antigen

i.e., T-lymphocytes, B lymphocytes, tumour necrosis factor-a

(TNFa) and interleukin (IL) which are capable of transducing

intracellular signals.

Cytotoxicity to the cell expressing target AG by ADCC or

CDC.

MECHANISM OF ACTION OF Mabs :

o Inhibition of growth factors: Epidermal growth factor

receptor (EGFR) is a cell surface receptor involved in

regulation of cell proliferation and survival. Also new

vessels grow to feed the cancer cells through this factor.

These factors can be inhibited to arrest growth of cancer

cells e.g., cetuximab act as EGFR inhibitor.

PHARMACOKINETICS

Mabs are used by intravascular route.

They have small volume of distribution and limited tissue

penetration.

They remain in circulation from 2days to 2 weeks.

Hour long infusions require a hospital environment and are

often associated with mild to very severe side effects.

SIDE EFFECTS:More common side effects

Allergic reactions, such as hives or itching

Flu-like symptoms, including chills, fatigue, fever, and muscle aches

and pains

Nausea

Diarrhea

Rare ---- more serious side effects

Infusion reactions. Severe allergy-like reactions can occur and, in very few

cases, lead to death

Dangerously low blood cell counts. Decreased red blood cells, white blood cells

and platelets

Cardiac complications Certain monoclonal antibodies may cause heart failure

and a small risk of MI

Bleeding. Some of the monoclonal antibody drugs are designed to stop cancer

from forming new blood vessels. There have been reports that these medications

can cause bleeding

Biosensors & Microarrays

Cancer , Transplant rejection,

Infectious diseases

Purification of drugs , Imaging

the target

Fight against Bioterrorism

When monoclonal antibody attaches to cancer cell :

Rituximab drug attaches to specific protein CD20 found on B cells

makes cell more visible to immune system

Cetuximab attaches to growth factor receptors , blocking its signal

and suppress cancer growth

Bevacizumab blocks growth signal which attract blood vessels then

tumor shrinks.

By combining radioactive particle with monoclonal antibodies,

radiation are deliver to cancer cells only , cancer cell dies.

RADIOIMMUNOTHERAPY

Involves the use of radioactively conjugated Murine antibodies against cellular antigens

Ex; Tositumomab ----- non-Hodgkins lymphoma.

CONCLUSION

Monoclonal antibodies are new biological agents that have good

clinical effects and an extended choice in the treatment spectrum to the

patients who were not responding to the existent treatments.

New therapeutic approaches are rapidly emerging and further studies

may help in designing more specific MAbs that would spare the

normal tissue, have less adverse effects and improve the patient’s

quality of life.