1. Morgane Sayes– Charette Group
Literature Meeting

2. Thomas H. Pillow Education Experiences
1996 – 2000 : BS Chemistry at Trinity University, San Antonio, Texas
2003 – 2009 : Ph.D, Organic Chemistry, Professor Paul A. Wender, Stanford University, California
Experiences
2000 – 2003 : Associate Manufacturing Engineer at
Sony Semiconductors
2009 – now : Chemistry Team Leader : Antibody-Drug Conjugates
(ADCs) at Genentech, San Francisco, California

3. Genentech Areas of research Numbers
Member of the Roche Group (March 2009)
Leading biotechnology company : treatment of patients with life-threatening medical conditions
Areas of research
Oncology
Immunology
Infectious diseases
Neuroscience
Metabolism
Ophtalmology
Numbers
13.3 K employees
11.3 K patents received
35 medicines on the market
19 Antibody-Drug Conjugates (ADCs)

4. Monoclonal Antibodies
Recognise and attach to specific proteins (antigen) produced by cancer cells
Naked monoclonal antibodies
Work by themselves
Trigger the immune system
Block molecules that stop the immune system
Block signals telling cancer cells to divide
Conjugated monoclonal antibodies
Joined to a chemotherapy drug or to a radioactive particle : used as a CARRIER
Reduce the damage to normal cells

5. Antibody-Drug Conjugates
Multistep sequence of events
Binding to the cell surface
Endocytosis
Trafficking to a lysosome
Proteolytic degradation
Diffusion of the released cytotoxic agent to the target
Cell death
Zhao, R. Y., Chari, R. V. J. et al., J. Med. Chem. 2011, 54,

6. Targeted drug delivery
Improvement of THERAPEUTIC INDEX and PHARMACOKINETICS of small molecule drugs
Need of a STABLE but LABILE connection to the drug
Chari, R. V. J., Miller, M. L., and Widdison, W. C., Angew. Chem. Int.Ed 2014, 53,

7. Targeted drug delivery
Active small
molecule drug
Antibody for specific
recognition
Cleavable linker (protease)
Wu, A. M. and Senter, P. D., Nature biotechnology 2005, 23,

8. Classification of linkers
Cleavage by enzymes such as proteases expressed either intra- or extracellularly
Best known example : cathepsin B in lysosomes
Elimination linkers
p-aminobenzyloxycarbonyl (PABC)
1,6-elimination
Requirement of a PRIMARY
or SECONDARY amine
(formation of carbamate
or amide)
Cyclization linkers
Kratz, F., Muller, I. A., Ryppa, C. and Warnecke, A., ChemMedChem 2008, 3,

9. Challenges Introduction of charges
PABCs used in half of the ADCs
Lack of DIVERSITY in drug structures
Too hydrophobic molecules
AGGREGATION
Introduction of charges
GPTR : hydrophobic protein (tetramer in native state)
T20 : HIV inhibitor peptide
May : Maytansine derivative (cytotoxic agent)
Adem, Y. T. et al., Biconjugate Chem. 2014, 25, ; Zhao, R. Y. et al., J. Med. Chem. 2011, 54,
Xiao, J., Burn, A. and Tolbert, T. J., Bioconjugate Chem. 2008, 19,

10. Tertiary and heteroaryl amines
Anticancer

11. Tertiary and heteroaryl amines
Antibacterial
Expand the scope of conjugatable complex small-molecule drugs
Generate a charged functional group
Goals

12. Auristatins and Tubulysins
Clinically validated mechanism of action but not sufficient activity at tolerated doses
Auristatin and MMAE : same activity
Adcetris (ADC)
R = H : 100-fold loss of potency
Conversion to a secondary amine NOT VIABLE

13. Concept Linker choice p-AminoBenzyl Quaternary amonium salt (PABQ)
Protease cleavable trigger :
Valine-citrulline dipeptide (ValCit)

14. Proof of concept Model of quaternary ammonium salt system
PBS buffer pH 7, 37 °C, overnight
STABLE
Exposure to cathepsin B

15. Concise and broadly applicable synthesis
Development of a SHORT synthesis of molecule containing a REACTIVE ELECTROPHILE
Protecting group FREE synthesis
Broad spectrum of NUCLEOPHILICITY (5 log variation in pKa)
Starting point
Benzyl bromide
Methanesulfonate

16. Concise and broadly applicable synthesis
Limited optimization
Strong base and acid sensitive
Temperature sensitive (> 40°C)
Low solubility (DMF or DMSO needed)
Best conditions
Multigram scale

17. Stability and release of the drugs
MRSA : Methicillin-Resistant S. aureus

18. Stability and release of the drugs
PABQ-9a
LC/MS chromatogram of reduced anti-MRSA-9c after digestion with cathepsin mixture
Efficient IMMOLATION

19. In vivo stability and efficacy studies
In vivo efficacy
EFFICACY
SELECTIVITY
DAR : Drug to Antibody ratio
Severe combined immunodefiency mice
Mice bearing WSU-DLCL2 human NHL xenographts

20. Hydrophobicity and log D
Correlation between AGGREGATION and LOG D
Log D = log P at a precise pH (7,4) for a compound of a specific pKa
MC-ValCit-PABC-MMAE : log D = 3,5
MC-ValCit-PABQ-AE : log D = 0,18
Resch-Genger, U. et al., Bioconjugate Chem. 2011, 22,
MC : Malemidocaproyl

21. Heteroaryl amine
Efficient IMMOLATION

22. Disulfide conjugates Protease cleavage in cytosol
Vlahov, I. et al., J. Org. Chem. 2007, 72,

23. Disulfide conjugates Protease cleavage in cytosol
Pillow, T. H. et al., Chem. Sci. 2016, ASAP.

24. Disulfide conjugates
Protease cleavage in cytosol

25. Improved therapeutic activity of ADCs
Carbamate linked conjugate
Quaternary ammonium linked conjugate
DNA31

26. Conclusion Increase the DIVERSITY of therapeutic agents
EFFICIENT, protecting group FREE synthesis for modification of tertiary and heteroaryl amines
STABILITY and generation of the FREE DRUG on TRIGGERING mechanisms
IMPROVEMENT in ACTIVITY over conjugate connected to carbamate
Possible application to INFECTIOUS DISEASES and INFLAMMATION