APPLICABILITY OF
TOXICOGENOMICS-BASED ASSAYS
WITHIN THE INDUSTRIAL CONTEXT
DR CARL WESTMORELAND
Slides available at www.TT21C.org
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Unilever is one of the world’s leading suppliers of fast-moving consumer goods. Our products are sold in over 190 countries and used by 2 billion consumers every day.
CAN WE USE A NEW INGREDIENT SAFELY?
Will it be safe • For our consumers? • For our workers? • For the environment?
Can we use x% of ingredient y in product z?
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TOXICITY ENDPOINTS (HUMAN HEALTH)
e.g. Relevant toxicity endpoints based on the Scientific Committee
on Consumer Products guidance document “Notes of Guidance for
the Testing of Cosmetic Substances and their Safety Evaluation”
• Acute toxicity
• Corrosivity and irritation
• Skin sensitisation
• Dermal/percutaneous absoprtion
• Repeated dose toxicity
• Reproductive toxicity
• Mutagenicity/genotoxicity
• Carcinogenicity
• Toxicokinetic studies
• Photo-induced toxicity
http://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_s_006.pdf
SAFETY ASSESSMENT PROCESS FOR INGREDIENTS IN CONSUMER PRODUCTS Consider product type
and consumer habits
Determine route and amount of exposure
Identify toxicological endpoints of potential
concern
Identify critical end point(s) for risk
assessment
Identify available toxicology data
Identify supporting safety data (e.g.
QSAR, HoSU)
Evaluate required vs. available support
Conduct risk assessment for each
critical endpoint
Conduct toxicology testing as required
Overall safety evaluation for product – define
acceptability and risk management measures 5
SAFETY ASSESSMENT PROCESS FOR INGREDIENTS IN CONSUMER PRODUCTS Consider product type
and consumer habits
Determine route and amount of exposure
Identify toxicological endpoints of potential
concern
Identify critical end point(s) for risk
assessment
Identify available toxicology data
Identify supporting safety data (e.g.
QSAR, HoSU)
Evaluate required vs. available support
Conduct risk assessment for each
critical endpoint
Conduct toxicology testing as required
Overall safety evaluation for product – define
acceptability and risk management measures 6
EU: SCCS OPINION 2010
‘…. majority of the
existing alternative
methods [are] only
suitable for hazard
identification of
cosmetic ingredients
and do not give
information on
potency. Thus, a full
human health risk
assessment cannot be
performed’
http://ec.europa.eu/health/scientific_committees/consumer_safety/statements/index_en.htm 7
CURRENT SCIENTIFIC REALITY: NON-ANIMAL APPROACHES FOR SAFETY DECISIONS
Human Health
Toxicology Endpoint
Timeline for Replacement of Animal
Testing
[Note: Regulatory Acceptance would require
an additional 4-8 years]
Comments
Repeated dose toxicity No timeline for full replacement could
be foreseen Ongoing work still at research stage
Carcinogenicity No timeline for full replacement could
be foreseen
Current in vitro test methods are
inadequate for generating the dose-
response information required for safety
assessment
Skin Sensitisation 2017 – 2019 for full replacement
Several non-animal test methods under
development & evaluation; data
integration approaches for safety
assessment required
Reproductive Toxicity No timeline for full replacement could
be foreseen
Ongoing work still at research stage
>2020 to identify key biological
pathways
Toxicokinetics No timeline for full replacement could
be foreseen
Ongoing work still at research stage
2015 – 2017: prediction of renal &
biliary excretion and lung absorption
Compiled from Adler et al (2011) Adler et al (2011), Archives in Toxicology, 85 (5) 367-485
Past:
• hazard focus
• emphasis on tests for classification and labelling (‘positives/negatives’)
• direct replacement of a specific animal test
NEW APPROACHES TO RISK ASSESSMENT WITHOUT ANIMALS
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NEW APPROACHES TO RISK ASSESSMENT WITHOUT ANIMALS
Now
» focus on non-animal approaches for consumer safety risk assessment
» data required for safety decision should be driver
» dose response information is essential
» understanding the underpinning human biology
» we are not looking for a way to do the animal test without the animal
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US NRC REPORT JUNE 2007
“Advances in toxicogenomics,
bioinformatics, systems
biology, epigenetics, and
computational toxicology could
transform toxicity testing from a
system based on whole-animal
testing to one founded primarily
on in vitro methods that
evaluate changes in biologic
processes using cells, cell
lines, or cellular components,
preferably of human origin.”
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ADVERSE OUTCOME PATHWAYS (AOP) SOURCE TO OUTCOME PATHWAYS (S2OP)
• Source to Outcome Pathways (Crofton et al, 2011)
Adapted from OECD (2012)
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• Proposal for a template and guidance on developing and assessing the Completeness of Adverse Outcome Pathways
Source Environmental Containment
Exposure Molecular Initiating
Event
Organelle Effects
Cellular Effects
Tissue Effects
Organ Effects
Organ Systems Effects
Individual Effects
Population Effects
Community Effects
PATHWAYS-BASED APPROACHES TO SAFETY ASSESSMENT
At the heart of all pathways-based approaches to safety assessment is the need for:
• Detailed mechanistic understanding of the biology which can lead to adverse effects in patients/consumers and workers
• Tools to interrogate these pathways with chemicals of interest
• Risk assessment approaches to combine dose response relationships with exposure information in humans
• The ability to be able to make a robust safety decision
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PATHWAYS-BASED APPROACHES TO SAFETY ASSESSMENT
At the heart of all pathways-based approaches to safety assessment is the need for:
• Detailed mechanistic understanding of the biology which can lead to adverse effects in patients/consumers and workers
• Tools to interrogate these pathways with chemicals of interest
• Risk assessment approaches to combined dose response relationships with exposure information in humans
• The ability to be able to make a robust safety decision
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A JOINT AMBITION
“Toxicogenomics - the application of genomics-based technologies in toxicological research - may provide tools to tackle these uncertainties. It also offers the opportunity to develop tests that require fewer laboratory animals or cause them less inconvenience, and may eventually replace animal tests completely by in vitro assays using animal or human cells”
This website represents the efforts Unilever and partners are taking to progress the science of toxicity pathways: to put in place the tools and novel thinking needed to implement TT21C/AOP- based risk assessments. In so doing, we aim to ultimately remove our dependence on apical endpoint toxicological studies and bring novel science to the decisions we make on the safe use of chemicals within consumer products www.tt21c.org 15
EXPLORING PATHWAYS-BASED RISK ASSESSMENT AT UNILEVER
• Systemic Toxicology Risk Assessment
- DNA damage
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A TT21C PROTOTYPE TOX PATHWAY (AOP): GENOTOXICITY/DNA DAMAGE
• Joint research program with Hamner Institutes • Develop tools to assess DNA-damage stress
pathways • Examine dose-dependent transitions for case-
study mutagenic compounds • Apply data to develop a computational systems
biology model of the p53-mdm2 network • Q: Can we use genotoxicity tox-pathway in TT21C
paradigm to provide a prototype proof of principle for TT21C/AOP?
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MODELLING ULTRASENSITIVITY IN P53 ACTIVATION
10-4
10-3
10-2
10-1
0
10
20
30
10-4
10-2
100
102
1
2
3
10-4
10-2
100
102
1
3
5
10-4
10-2
100
102
1
3
5
7
9
ATM γH2AX
p53 Micronuclei F
old
ch
an
ge
Etoposide (μM)
Fo
ld c
ha
ng
e
Etoposide (μM)
Etoposide (μM) Etoposide (μM)
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IN VITRO TO IN VIVO (HUMAN EXPOSURE) EXTRAPOLATION
Exposure
mg/kg/day Target site
concentration
(µM)
In vitro
adaptive/adverse
threshold
concentration (µM)
– measuring &
modelling FREE
CONCENTRATIONS
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Exposure & Consumer Use Assessment
High-content information in vitro assays in human cells & models
Dose-response assessments
Computational models of the circuitry of the relevant toxicity pathways
PBPK models supporting in vitro to in vivo extrapolations
Risk assessment based on exposures below the levels of significant pathway perturbations 21
A LONG-TERM VISION: SOURCE TO OUTCOME PATHWAY-BASED SAFETY RISK ASSESSMENT
• fully integrated exposure and hazard assessment at different levels of biological organisation
To reduce uncertainty
within our risk assessments…
...we will focus on
characterising the key
impacts…
…and replace our current reliance on
apical endpoint studies…
...of marketing any new
ingredient via:
• greater mechanistic understanding of ingredient properties to allow extrapolation from Molecular Initiating Events (MIEs) to an adverse outcome
• better communication of acceptable risk using defined protection goals (consumer, environmental)
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ACKNOWLEDGEMENTS
Yeyejide Adeleye, Maja Aleksic, Nora Aptula, Mahesh Batakurki, Emma Butler, Paul Carmichael, Stella Cochrane, Sarah Cooper, Carol Courage, René Crevel,
Richard Cubberley, Tom Cull, Claire Davies, Michael Davies, Eliot Deag, Matthew Dent, Sue Edwards, Julia Fentem, Chris Finnegan, Paul Fowler, Antonio Franco, Nichola Gellatly, Nicola Gilmour, Stephen Glavin, Dave Gore, Todd Gouin, Steve
Gutsell, Colin Hastie, Juliette Hodges, Geoff Hodges, Sandrine Jacquoilleot, Gaurav Jain, Penny Jones, Sarah Kang-King-Yu, Anja Lalljie, Yvan Le Marc, Moira Ledbetter, Jin Li, Cameron MacKay, Ian Malcomber, Sophie Malcomber, Stuart
Marshall, Gavin Maxwell, Helen Minter, Craig Moore, Beate Nicol, Sean O’Connor, Deborah Parkin, Ruth Pendlington, Juliette Pickles, Mike Pleasants,
Oliver Price, Fiona Reynolds, Jayne Roberts, Nicola Roche, Paul Russell, Ouarda Saib, David Sanders, Paul Sanderson, Gary Sassano, Andrew Scott, Sharon Scott, David Sheffield, Nikol Simecek, Wendy Simpson, Ilias Soumpasis, Chris Sparham,
Richard Stark, Vicki Summerfield, Diana Suárez-Rodriguez, Dawei Tang, Jeff Temblay, Sivaram TK, Roger van Egmond, Carl Westmoreland, Andrew White &
Sam Windebank 23