NAMs- prospects, challenges and limits FOR RISK ASSESSMENT Tewes - - PowerPoint PPT Presentation

▶
nams prospects challenges and limits
SMART_READER_LITE
LIVE PREVIEW

NAMs- prospects, challenges and limits FOR RISK ASSESSMENT Tewes - - PowerPoint PPT Presentation

Dec 26, 2022 11 likes •195 views

GERMAN FEDERAL INSTITUTE NAMs- prospects, challenges and limits FOR RISK ASSESSMENT Tewes Tralau Regulatory Status Quo : Where do we stand? Consumer products / Contaminants: Heterogeneous ( REACH, product-specific regulations, ALARA ), cave: in

slide-1
SLIDE 1

GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT

NAMs- prospects, challenges and limits

Tewes Tralau

slide-2
SLIDE 2
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 2

Regulatory Status Quo: Where do we stand?

Pesticides & Biocides: Harmonised guidelines (OECD, EU), mostly in vivo, mechanistic data only as “add-on”. Food & Feed: Most testing is done in vivo, non-animal methods comprise PBTK modelling and TTC. REACH & CLP: Harmonised guidelines, mostly in vivo, mechanistic studies currently treated as “add-

  • n”. Rely on data-sharing & "read across"

(SAR) Consumer products / Contaminants: Heterogeneous (REACH, product-specific regulations, ALARA), cave: in vivo ban (cosmetics), nanotox, EDCs, mixtures ...

At the same time:

  • Pressure to move away from in vivo testing.
  • Arbitrary political deadlines for doing so range

from 2025 (NL) to 2035 (US-EPA).

  • Successful use of alternatives for hazard

ranking/prioritisation and read across.

slide-3
SLIDE 3
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 3

Regulatory requirements

Primary objective is public health protection!

This means safety testing must allow

  • clear conclusions regarding the potential adversity in an intact organism,
  • clear conclusions regarding dose-response relationships,
  • provide legal certainty,
  • refer to set and accepted testing guidelines,
  • and, ideally, should have earned some trust (e.g., by standing the test of time).
slide-4
SLIDE 4
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 4

Primary objective is public health protection!

This means safety testing must allow

  • clear conclusions regarding the potential adversity in an intact organism,
  • clear conclusions regarding dose-response relationships,
  • provide legal certainty,
  • refer to set and accepted testing guidelines,
  • and, ideally, should have earned some trust (e.g., by standing the test of time).

Regulatory requirements

Current system - PROs: a) Established methods, b) mostly harmonised legal framework, c) long experience, d) trusted results, e) predictability of legal procedures.

slide-5
SLIDE 5
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 5

Primary objective is public health protection!

This means safety testing must allow

  • clear conclusions regarding the potential adversity in an intact organism,
  • clear conclusions regarding dose-response relationships,
  • provide legal certainty,
  • refer to set and accepted testing guidelines,
  • and, ideally, should have earned some trust (e.g., by standing the test of time).

Regulatory requirements

Current system - CONs: a) Capacity issues: > 80,000 chemicals, increasing by ~ 2,000/a a) Not all questions or endpoints addressed/addressable (e.g., residues, mixtures, low dose effects, neurotoxicity, ED- or epigenetics…). b) Worries about species specific effects (metabolism/microbiome). c) Societal pressure/ethics.

slide-6
SLIDE 6
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 6

Case for change – “classical” testing vs. NAMs

Adapted from Tralau & Luch, Arch. Toxicol. 2015, 89: 819-21

slide-7
SLIDE 7
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 7

NAMs – basic considerations & concepts

NAM approaches allow to:

  • Characterise molecular targets and the respective pathways affected.
  • Classify and rank substances according to their potential for cellular interference.
  • Identify substances with no effect.
  • Identify biomarkers and signatures.
  • Build testing strategies by using a versatile modular setup.

Inherent issues:

  • Limited compatibility to the grown histopathological picture of adversity.
  • They do not easily translate into established quantitative measures of risk assessment.
  • Prone to over predictability …
slide-8
SLIDE 8
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 8

NAMs – considerations & concepts

“Advanced Outcome Pathways”

Identification of endpoint-specific events & signalling cascades suitable to define adverse outcome

“Mechanistic Integrated Testing Strategies” “Relevant Pathways of Toxicological Concern”

Entity of pathways with the potential for adversity, the network of which leads to the “toxome”

Figure by M. Whelan Tralau et al., EHP 2012, 120: 1498-94

slide-9
SLIDE 9
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 9

Current state of the art

Cellular and biochemical assays for ≥ 600 endpoints This includes:

  • Molecular & biochemical assays
  • Cell lines
  • Primary cells
  • Designed cells (transformed)

Adapted from Tralau & Luch, TiPS 2012, 33: 353-64

slide-10
SLIDE 10
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 10

Where are we on the way to a Tox-test dummy?

Current use of NAMs for:

  • Biomarker identification.
  • Substantiating read across.
  • Screening & hazard identification, prioritisation.
  • Exclusion of risk and hence further testing (e.g. mutagenicity, genotoxicity or skin corrosion).
  • Substance classification (e.g., skin corrosion and irritation).
  • As part of tiered testing strategies (e.g., tier 1 for “endocrine disruption”).
  • Use of organotypic (cell and tissue) cultures to assess aspects of organ toxicity (e.g., skin).
  • Use of PBTK models for internal exposure assessment (in vivo & in vitro).
slide-11
SLIDE 11
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 11

Where are we on the way to a Tox-test dummy?

From a scientific perspective current state of the art NAMs (in silico, in vitro, “omics“…) Are fit to deliver data suitable for assessing many aspects of potential organ toxicity and, to a limited extent, also parts of chronic toxicity. However, more complex endpoints often still need further development in terms of system stability and complexity (tissue interaction, metabolism, immunocompetence) as well as with regard to in vivo to in vitro extrapolation.

Tralau et al., EHP 2012, 120: 1498-94

slide-12
SLIDE 12
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 12

Principal open issues – regulatory side

Cellular and biochemical assays for ≥ 600 endpoints This includes:

  • Molecular & biochemical assays
  • Cell lines
  • Primary cells
  • Designed cells (transformed)

(Regulatory) acceptance

  • Validation does not necessarily warrant acceptance… The latter also depends on experience and

trust into the method. This should be addressed by blinded cross-validation trials alongside established assays. Also, there often still is a substantial skill gap on both sides (regulatory as well as on the “science” side). Adversity & Plasticity

  • Need to convert molecular measures into quantitative (or probabilistic) measures suitable for

risk assessment. Need for (pre)adverse “signatures” and databases thereof.

  • Need to (partly) rethink adversity (biomarker based vs. histopathology-based).
  • How to address plasticity? Can one agree on biomarkers that define the ‘point-of-no-return’?
  • Need for improved in vitro/in vivo correlations.

Test System Physiology

  • Test systems used should be adequate and sufficiently complex (long term testing, metabolism).

Test System Validation

  • How do we validate and do we do so against the right standards? How “golden” are they?

Informed decisions on method performance and testing reliability require sound comparable performance parameters.

slide-13
SLIDE 13
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 13

Principal open issues – regulatory side

Cellular and biochemical assays for ≥ 600 endpoints This includes:

  • Molecular & biochemical assays
  • Cell lines
  • Primary cells
  • Designed cells (transformed)

(Regulatory) acceptance

  • Validation does not necessarily warrant acceptance… The latter also depends on experience and

trust into the method. This should be addressed by blinded cross-validation trials alongside established assays. Also, there often still is a substantial skill gap on both sides (regulatory as well as on the “science” side). Adversity & Plasticity

  • Need to convert molecular measures into quantitative (or probabilistic) measures suitable for

risk assessment. Need for (pre)adverse “signatures” and databases thereof.

  • Need to (partly) rethink adversity (biomarker based vs. histopathology-based).
  • How to address plasticity? Can one agree on biomarkers that define the ‘point-of-no-return’?
  • Need for improved in vitro/in vivo correlations.

Test System Physiology

  • Test systems used should be adequate and sufficiently complex (long term testing, metabolism).

Test System Validation

  • How do we validate and do we do so against the right standards? How “golden” are they?

Informed decisions on method performance and testing reliability require sound comparable performance parameters.

slide-14
SLIDE 14
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 14

Fields of action

Cellular and biochemical assays for ≥ 600 endpoints This includes:

  • Molecular & biochemical assays
  • Cell lines
  • Primary cells
  • Designed cells (transformed)
  • Engage with NAM-development and application on the level of academia, test developers and
  • industry. Foster a culture of dialogue and better understanding for what kind of tests are possible,

which ones are needed and what current systems can deliver.

  • Identification of quantifiable molecular signatures that result in adverse phenotypes of

toxicological relevance. Concomitant establishment of a molecular “background”. Readouts should ideally differentiate between background, preadverse and adverse reactions as well as adaptative processes. Respective approaches could follow a classic deterministic lead or, alternatively, rely on probabilistic methods.

  • Systematic performance review of the available methods in order to facilitate scientifically based

decisions on the best testing strategies. Predictivity and reliability are key for the acceptability of testing methods. Yet, particularly for many of the established methods these parameters have never been evaluated systematically. This often makes a quantifiable comparison impossible and introduces a “gold standard”-bias which not only flaws the judgement on test performance but at worst prevents better testing.

  • (Pre)validation of existing and new systems in blinded trials vs. (existing) in vivo data. Reliance
  • n performance standards and pilot studies instead of full blown validation trails.
slide-15
SLIDE 15
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 15

Fields of action

Cellular and biochemical assays for ≥ 600 endpoints This includes:

  • Molecular & biochemical assays
  • Cell lines
  • Primary cells
  • Designed cells (transformed)
  • Engage with NAM-development and application on the level of academia, test developers and
  • industry. Foster a culture of dialogue and better understanding for what kind of tests are needed

and what current systems can deliver.

  • Identification of quantifiable molecular signatures that result in adverse phenotypes of

toxicological relevance. Concomitant establishment of a molecular “background”. Readouts should ideally differentiate between molecular background, preadverse and adverse reactions as well as adaptative processes. Respective approaches could follow a classic deterministic lead or, alternatively, rely on probabilistic methods.

  • Systematic performance review of the available methods in order to facilitate scientifically based

decisions on the best testing strategies. Predictivity and reliability are key for the acceptability of testing methods. Yet, particularly for many of the established methods these parameters have never been evaluated systematically. This often makes a quantifiable comparison impossible and introduces a “gold standard”-bias which not only flaws the judgement on test performance but at worst prevents better testing.

  • (Pre)validation of existing and new systems in blinded trials vs. (existing) in vivo data. Reliance
  • n performance standards and pilot studies instead of full blown validation trails.

R e g u l a t

  • r

y s c i e n c e !

slide-16
SLIDE 16
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 16

Current activities - BfR

Research:

  • Own and third party funded projects addressing open issues and the applicability of new assays.

This includes assay development & pre-validation, biomarker identification as well as research on toxicological mechanisms, substance hazards, exposure, analytical methods and epidemiology. Third party funded activities comprise several Horizon 2020 projects and their successors (incl. Euromix and EU-ToxRisk ), the MEAL-study for improved exposure data and projects from various

  • ther calls (incl. EFSA).

Modelling:

  • Assessment of grouping by biological activity instead of structural similarity as well as toxicokinetic

and exposure modelling. Conceptual:

  • Active participation in working groups and advisory panels

(OECD, incl. AOPs and IATAs, ECHA, EFSA, Horizon 2020).

  • Liaising and exchange with partner agencies and think tanks, particularly across Europe, the US and

Japan.

  • Efforts in support of harmonisation of data requests, standards and concepts.
  • Internal working groups (NAMs, testing methods and endpoint specific).
  • Concept papers and workshops.
slide-17
SLIDE 17
  • T. Tralau, July 2nd 2020, 76th meeting of the EFSA advisory forum

page 17

t4 Workshop Report*

Non-Animal Models of Epithelial Barriers (Skin, Intestine and Lung) in Research, Industrial Applications and Regulatory Toxicology

Sarah Gordon 1, Mardas Daneshian 2, Joke Bouwstra 3, Francesca Caloni 4, Samuel Constant 5, Donna E. Davies 6,7, Gudrun Dandekar 8, Carlos A. Guzman 9, Eric Fabian10, Eleonore Haltner 11, Thomas Hartung2,12, Nina Hasiwa2, Patrick Hayden13, Helena Kandarova14, Sangeeta Khare15, Harald F. Krug16, Carsten Kneuer

17,

Marcel Leist2, Guoping Lian18,19, Uwe Marx20,21, Marco Metzger 8, Katharina Ott10, Pilar Prieto 22, Michael S. Roberts 23, Erwin L. Roggen 24, Tewes Tralau 25, Claudia van den Braak 26, Heike Walles 8 and Claus-Michael Lehr 1

1Department of Drug Delivery, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research (HZI) Doerenkamp Zbinden Foundation. The views expressed in this article are those of the contributing authors and do not necessarily reflect those of their institution of

Arch Toxicol (2015) 89:819–821 DOI 10.1007/s00204-015-1511-z

GUEST EDITORIAL

Moving from rats to cellular omics in regulatory toxicology: great challenge toward sustainability or “up-shit-creek without a paddle”?

Tewes Tralau1 · Andreas Luch1 Arch Toxicol (2015) 89:823–850 DOI 10.1007/s00204-015-1510-0

REVIEW ARTICLE

Regulatory toxicology in the twenty-first century: challenges, perspectives and possible solutions

Tewes Tralau1 · Michael Oelgeschläger1 · Rainer Gürtler1 · Gerhard Heinemeyer1 · Matthias Herzler1 · Thomas Höfer1 · Heike Itter1 · Thomas Kuhl1 · Nikola Lange1 · Nicole Lorenz1 · Christine Müller-Graf1 · Ulrike Pabel1 · Ralph Pirow1 · Vera Ritz1 · Helmut Schafft1 · Heiko Schneider1 · Thomas Schulz1 · David Schumacher1 · Sebastian Zellmer1 · Gaby Fleur-Böl1 · Matthias Greiner1 · Monika Lahrssen-Wiederholt1 · Alfonso Lampen1 · Andreas Luch1 · Gilbert Schönfelder1 · Roland Solecki1 · Reiner Wittkowski1 · Andreas Hensel1

slide-18
SLIDE 18

GERMAN FEDERAL INSTITUTE FOR RISK ASSESSMENT

Thank you for your attention! Questions?

  • T. Tralau

German Federal Institute for Risk Assessment Department of Food Safety Max-Dohrn Str. 8-10 l D-10589 Berlin l Germany +49-30-18412-25000 , tewes.tralau@bfr.bund.de