Transcript Antibody-Drug Conjugates

Morgane Sayes– Charette Group
Literature Meeting
16-11-2016
Thomas H. Pillow
Education
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
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Genentech
Member of the Roche Group (March 2009)
Leading biotechnology company : treatment of patients with life-threatening medical conditions
Areas of research
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Oncology
Immunology
Infectious diseases
Neuroscience
Metabolism
Ophtalmology
Numbers
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13.3 K employees
11.3 K patents received
35 medicines on the market
19 Antibody-Drug Conjugates (ADCs)
https://www.gene.com
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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
http://www.cancerresearchuk.org
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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, 3606-3623.
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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, 3796-3827.
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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, 1137-1146.
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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
Cyclization linkers
Requirement of a PRIMARY
or SECONDARY amine
(formation of carbamate
or amide)
Kratz, F., Muller, I. A., Ryppa, C. and Warnecke, A., ChemMedChem 2008, 3, 20-53.
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Challenges
PABCs used in half of the ADCs
Lack of DIVERSITY in drug structures
Too hydrophobic molecules
AGGREGATION
Introduction of charges
May : Maytansine derivative (cytotoxic agent)
GPTR : hydrophobic protein (tetramer in native state)
T20 : HIV inhibitor peptide
Adem, Y. T. et al., Biconjugate Chem. 2014, 25, 656-664. ; Zhao, R. Y. et al., J. Med. Chem. 2011, 54, 3606-3623.
Xiao, J., Burn, A. and Tolbert, T. J., Bioconjugate Chem. 2008, 19, 1113-1118.
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Tertiary and heteroaryl amines
Anticancer
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Tertiary and heteroaryl amines
Antibacterial
Goals
- Expand the scope of conjugatable complex small-molecule drugs
- Generate a charged functional group
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Auristatins and Tubulysins
Clinically validated mechanism of action but not sufficient activity at tolerated doses
Auristatin and MMAE : same activity
R = H : 100-fold loss of potency
Adcetris (ADC)
Conversion to a secondary amine NOT VIABLE
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Concept
p-AminoBenzyl Quaternary amonium salt (PABQ)
Linker choice
Protease cleavable trigger :
Valine-citrulline dipeptide (ValCit)
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Proof of concept
Model of quaternary ammonium salt system
PBS buffer pH 7, 37 °C, overnight
STABLE
Exposure to cathepsin B
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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
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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
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Stability and release of the drugs
MRSA : Methicillin-Resistant S. aureus
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Stability and release of the drugs
9a
PABQ-9a
LC/MS chromatogram of reduced anti-MRSA-9c after digestion with cathepsin mixture
Efficient IMMOLATION
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In vivo stability and efficacy studies
In vivo stability
In vivo efficacy
EFFICACY
SELECTIVITY
DAR : Drug to Antibody ratio
Severe combined immunodefiency mice
Mice bearing WSU-DLCL2 human NHL xenographts
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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, 1298-1308.
MC : Malemidocaproyl
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Heteroaryl amine
Efficient IMMOLATION
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Disulfide conjugates
Protease cleavage in cytosol
Vlahov, I. et al., J. Org. Chem. 2007, 72, 5968-5972.
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Disulfide conjugates
Protease cleavage in cytosol
Pillow, T. H. et al., Chem. Sci. 2016, ASAP.
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Disulfide conjugates
Protease cleavage in cytosol
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Improved therapeutic activity of ADCs
Carbamate linked conjugate
Quaternary ammonium linked conjugate
DNA31
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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
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