This presentation is about an article in target therapy that written by John Y. Li 2016

1. A Biparatopic HER2-Targeting Antibody-Drug
Conjugate Induces Tumor Regression in
Primary Models Refractory to or Ineligible for
HER2-Targeted Therapy
Cancer Cell (IF 23.523)
Authors:
John Y. Li, Samuel R. Perry,
Vanessa Muniz-Medina, ...,
Rakesh Dixit, Jane K. Osbourn,
Steven R. Coats
Year:2016
Presented by: Mahshid Moballegh Nasery
MSc student of toxicology 1
http://lms.bums.ac.ir

2. HER2:
Human epidermal growth factor receptor 2
HER2:
Is a receptor tyrosine kinase that is involved in the regulation of
various cellular functions.
Aberrant HER2 receptor activation
tumorigenesis
Progression of a number of cancers
Receptor tyrosine kinases are typically routed to lysosomes for
degradation ligand binding
(is a major negative feedback mechanism regulating the intensity and
duration of receptor activation)
Presentedby:M.Moballegh
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3. 3
HER2:
Human epidermal growth factor receptor 2
pubweb.fccc.edu
Presentedby:M.Moballegh

4. Monoclonal antibodies(MAB)
Monoclonal antibodies an effective therapy for treating HER2
positive metastatic breast cancer
Three HER2-specific MAB:
trastuzumab
pertuzumab
ado-trastuzumab emtansine
(T-DM1)
Presentedby:M.Moballegh
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5. Monoclonal antibody 39S
Monoclonal antibody 39S
Is a fully human antibody against HER2
Capable of blocking HER2/HER3 receptor
phosphorylation in heregulin-1b-treated cancer cells
Presentedby:M.Moballegh
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6. Antibody-drug conjugates (ADCs)
Antibody-drug conjugates (ADCs) :
A class of drugs that use antibodies specifically targeting tumor-associated
antigens as vehicles to deliver covalently attached small-molecule toxins
into cancer cells
T-DM1 :
Consists of trastuzumab coupled with the microtubule poison
maytansinoid DM1 through a thioether linker
The amount of toxin released into the cytoplasm
determines the cell killing potency of an ADC
Presentedby:M.Moballegh
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7. 7
Antibody-drug conjugates (ADCs)
Presentedby:M.Moballegh

8. Survey in this article
 Constructeda biparatopic HER2-targeting ADC
 Characterized its anti-tumor activity
 Evaluated its safety profile and therapeutic potential in treating
breast cancer patients who are refractory to or ineligible for
current HER2-targeted therapies
Presentedby:M.Moballegh
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9. 9
In Brief
Presentedby:M.Moballegh

10. Construction of Anti-HER2 Biparatopic Antibody
Presentedby:M.Moballegh
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11. The Biparatopic Antibody Promotes HER2 Clustering
and Lysosomal Degradation
Presentedby:M.Moballegh
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12. Biparatopic Antibody> Trastuzumab+39s>Pertuzumab+39s> 39s>
Trastuzumab+pertuzumab> trastuzumabPertuzumab>
Biparatopic Antibody > Trastuzumab+39s > Trastuzumab+pertuzumab >
39s> Pertuzumab > Trastuzumab
HER2 receptor internalization induced by the
biparatopic antibody
HER2
degradation
Presentedby:M.Moballegh
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13. The Biparatopic Antibody Promotes HER2 Clustering
and Lysosomal Degradation
Presentedby:M.Moballegh
Scale=5um
Ab cons:50 nM
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14. Biparatopic ADC Demonstrates Potent, Target-Mediated
Cytotoxic Activity
The biparatopic antibody contains
three site mutations in the Fc region
It is thought that these mutations may minimize the FcgR-mediated, HER2
independent uptake of ADC by normal tissues, thereby reducing off-target
toxicity such as thrombocytopenia
To confirm that the conjugation of tubulysin did not alter the binding
characteristics of the biparatopic antibody:
Compared binding activities of the biparatopic ADC to its parental unconjugated
antibody.
The biparatopic ADC retained the target binding specificity and affinity to HER2
identical to its parental unconjugated antibody
S239C
S442C
L234F
Presentedby:M.Moballegh
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15.  Treated the cells with the biparatopic ADC or T DM1 and then
examined cell viability
Biparatopic ADC Demonstrates Potent, Target
Mediated Cytotoxic Activity in a Panel of Cancer
Cell Lines Expressing Different Levels of HER2
 The results demonstrated :
That the cell killing activity was generally correlated to the
level of HER2 expression on the cell surface
Presentedby:M.Moballegh
HER2 more effect
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16. Comparison between biparatopic ADC &TDM1 in
cytotoicity activity:
Presentedby:M.Moballegh
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17. Biparatopic ADC Demonstrates Potent, Target-Mediated
Cytotoxic Activity in a Panel of Cancer Cell Lines
Expressing Different Levels of HER2
Presentedby:M.Moballegh
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18. The biparatopic ADC is inactive in the NCI-H69
xenograft model
Presentedby:M.Moballegh
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19. Confocal microscopy images of SKOV-3 cells
mode of action of the biparatopic ADC
Presentedby:M.Moballegh
Scale bars, 10 mm
5 nM each ADC 19

20. To determine the in vivo anti-tumor activity of the biparatopic ADC:
tested the molecule in tumor models representing
Different breast cancer patient subpopulations classified by HER2
expression
Hercept test:
3
2
1
Presentedby:M.Moballegh
anti-tumor activity(in vivo )
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21. Biparatopic ADC Induces Tumor Regression in In Vivo
Xenograft Models Representing Different Patient
Subpopulations of Breast Cancer
Presentedby:M.Moballegh
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22. Biparatopic ADC Demonstrates Potent Anti-Tumor
Activity in Primary Breast Cancer Models Representing
HER2-Negative/T-DM1 Ineligible Patients
Presentedby:M.Moballegh
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23. Immunohistochemistry (IHC) analysis of the 17 PDX models
high heterogeneity of HER2 expression in these tumors.
Biparatopic ADC Demonstrates Bystander Killing
Activity
Despite such diverse heterogeneity of HER2 expression treatment
with the biparatopic sustained tumor regression in many of
the models
Hypothesized Biparatopic ADC may be able to kill non-HER2
expressing tumor cells through a bystander
mechanism
Presentedby:M.Moballegh
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24. Biparatopic ADC Demonstrates Strong Bystander Killing
Activity
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Presentedby:M.Moballegh

25. Adverse effect
Nonclinical safety of the biparatopic ADC assessed in cynomolgus monkeys
 Good-laboratory- practice (GLP) toxicology study
Worldwide Primates is a leading supplier of premium
quality non-human primate models for research,
including government, university, and
pharmaceutical level facilities
• Species: Cynomolgus Monkeys
• Scientific Name: Macaca fascicularis
• Origin: China, Indonesia, Mauritius
• Weight Range: 1.7 Kg - 8.0 Kg
Presentedby:M.Moballegh
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wwprimates.com

26. Adverse effect
 Unconjugated biparatopic antibody did not induce any adverse
effects in monkeys at all doses that had been tested
 The dose-limiting toxicity caused by the biparatopic ADC in monkeys
is epithelial degeneration in the gastrointestinal tract.
 There was no evidence of cardiotoxicity(Despite a marginal level of
HER2 expression on cardiomyocytes)
Assessed by:
Electrocardiogram, cardiac troponin I levels, and detailed histopathological
evaluation in the GLP toxicity study
 The biparatopic ADC did not cause dose-limiting adverse effects
on platelets in monkeys(unlike T-DM1, which is well known to cause dose-
limiting thrombocytopenia)
Presentedby:M.Moballegh
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27. Question
HER2 expression in normal tissues (although at a marginally detectable level )
skin cardiac muscl epithelium of mammary gland gastrointestinal tract
The key mechanism of action for the biparatopic ADC is:
• To induce HER2 clustering
• Triggers enhanced internalization and lysosomal trafficking
more toxins to be delivered into the target cells
The formation of the antibody-antigen matrix triggered by the biparatopic antbody
Is largely dependent on the HER2 level.
Presentedby:M.Moballegh
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28. Thank you for your attention
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