Center for Alternatives to Animal Testing (CAAT)

Johns Hopkins University, Baltimore, USA –

University of Konstanz, GermanyFrancois Busquet, PhD

Definition of

adverse effects in

EDC toxicology

Outlook

• EU stakeholders mindset• Examples of strategies / point of views of

different actors on adverse effects for edc• IVT challenges to convince the stakeholders

• Regulators want a toolbox that is understandable, sound and reliable (hazard identification, characterization, risk etc…)

• Policy makers (EC + EP) want to protect the sensitive population and ensure sustainable trade (risk management)

• Industry want a toolbox that discriminate accurately the compounds and avoid false positive

• Public opinion wants transparency & action • NGOs want more environment, consumer, workers protection ( =

more in vivo tests) & banning/restriction of suspected molecules• Animal welfare NGOs want NO animal testing• Can the science (endocrinologists, toxicologists, academician..)

do the synthesis? How can we move on based on in vitro tools?

EU Stakeholders Mindset

EXAMPLE OF

STRATEGIES ON

ADVERSE EFFECTS

FOR EDC

EFSA

EFSA JOURNAL 2013; 11 (3)3132 – scientific opinion

ECHA

Peer-Review

Peer-Review

US EDSP

US EDSP

FIFRA: Federal Insecticide, Fungicide, and Rodenticide Act

U.S. Environmental Protection Agency Endocrine Disruptor Screening Program Comprehensive Management Plan

US EDSP

EDSP20

Max $1 million / ingredient

EDSP21

=

in vitro HTS

in silico

Full

replacement

for Tier 1<$30,000 / ingredient

EDSP20

Max $1 million / ingredient

EDSP21

=

in vitro HTS

in silico

Full

replacement

for Tier 1<$30,000 / ingredient

TOXCASTTM

TOXCASTTM

EPA–HQ–OPPT–2015–0305; FRL–9928–69

NEXT TARGET

NEXT TARGET

TIER 2:• AVIAN TWO GENERATION• FISH LIFECYCLE (MEDAKA

MULTIGENERATION TEST)• INVERTEBRATE MYSID LIFECYCLE• MAMMALIAN TWO

GENERATIONS• IN UTERO THROUGH LACTATION

EPA–HQ–OPPT–2015–0305; FRL–9928–69

TiPEDThe Tiered Protocol for Endocrine Disruption

TIPED is not meant to be used

for regulatory actions. It is a

non-exhaustive, flexible

approach where end-users are

chemists.

Schug et al. Designing endocrine disruption out of the next generation of chemicals. Green Chem., 2013, 15, 181

OECD Conceptual

Framework

Previous version 2002

Specific or updated US TIER 1

Not specific devt

Specific or updated

US TIER 1

12 TG adopted in 5 years; time frame 2007 -2012

Not specific devt

Specific or updated

Few comments: •Quantity vs. quality for level4 &level5 => Tinkering?•Permeability with the US EDSP => How to take advantages of recent US Tier1 changes?

US TIER 2

OECD GD150• Level 4:

• B33: The results for a chemical tested in the male or female pubertal assays with only two dose levels may not provide sufficient information on adverse effects. However, for ecological systems, effects on apical endpoints at this level, such as fecundity, would be considered adverse.

• B34: Effects on some endpoints included in the assays can be considered as adverse apical impacts (e.g. major histopathologic changes in reproductive organs in rats; biased phenotypic sex ratios in developing fish)

OECD GD150• Level 5:

• B43: Endpoints sensitive to endocrine disruption, not specified in OECD TG 416, include areola/nipple retention, anogenital distance at birth, measurement of thyroid hormones and TSH levels. Effects on the developing nervous and immune systems are also not (?) assessed.

=> OECD TG 443 (i.e. extended one generation) is presented as the most exhaustive and reliable method to detect EDC: adverse effects are morphological and analytical for mammalian toxicology

In vivo tests

•OPENING THE BLACK BOX

•CONNECTING THE DOTS

•EXTRAPOLATION FROM IN VITRO TO IN VIVO

OECD AOP

OECD AOP

OECD AOP

OECD AOP

AFTER VALIDATING AN AOP, IS IT OK TO GENERATE ONLY IN VITRO DATA

AFTERWARDS?

DRP 178

IVT Challenges (1) to

convince the stakeholders• Looking at sensitive population (time, window)• Looking at brain development (tissue specific) = IQ

loss• Looking at repeated exposure (long-term)• Looking at genital malformations (hypospadia)• Looking for a dose/concentration for extrapolation• Looking at places we have not yet looked at or think

about

IVT Challenges (2) to

convince the stakeholders• What is the purpose of

detection adverse effect in Tox?• => To regulate or so to say filter

“the good, the bad and the ugly” compounds

• Consensus on edc definition & therefore need to display, measure adverse effects in vivo

What to do afterwards

with the workshop?

• November 2015: European Commission

workshop in Brussels organised by DG

ENV? => obvious since it is a LIFE

project?

• ECHA Endocrine Disruptor Expert Group?

• OECD expert group on EDC?