The conversion of Saul to St Paul (Michelangelo, 1542)

Marcel LeistDoerenkamp-Zbinden ChairFor Alternative in vitro Methods,University Konstanz, KonstanzGermany

EPAA Annual Conference 2007

Regulatory acceptance and implementation of 3Rs approaches

Criteria and Drivers for Acceptance

Regulatory acceptance

Aca

dem

ia

Feedback processes?Developers

3R test pipeline

Major drivers for 3R

3Ranimals

confidence

Validation

Experience

Communication

Optimised strategies

(De)validation

Confidence as key factor for regulatory acceptance of alternatives

Validation of old AND new methods

Safety levels, robustness, assay characteristics, ....

…also heterogeneity in the design of the available in vivo studies underlies much of the scatter, and this puts a limit on validating in vitro data as predictors of in vivo data. Further analysis of the in vitro-in vivo correlation would therefore require high quality in vivo data, …..

Quantitative extrapolation of in vitro whole embryo culture embryotoxicity data to developmental toxicity in vivo using the Benchmark Dose approach.

A.H. Piersma et al, (2007) Toxicol. Sci.

Problems with in vivo assays....:

…also heterogeneity in the design of the available in vivo studies underlies much of the scatter, and this puts a limit on validating in vitro data as predictors of in vivo data. Further analysis of the in vitro-in vivo correlation would therefore require high quality in vivo data, …..

Quantitative extrapolation of in vitro whole embryo culture embryotoxicity data to developmental toxicity in vivo using the Benchmark Dose approach.

A.H. Piersma et al, (2007) Toxicol. Sci.

Example:

Avoidance of prejudice: „....in vitro systems do not predict systemic toxicity......, in vivo systems are better“

Example: TeGenero TGN1412

The Journal of Immunology (2007), 179, 3325

Prejudice: in vitro systems do not predict systemic toxicity

The 3R

Reduce Replace

Refine

Driver for regulatory acceptanceof „reduction“

„Enough is enough“

- LD50- Ecotoxicology test strategies- Two-generation studies

…study retrospectively evaluates 176 multi-generation studies to assess potential differences between the first and the second generation, both in terms of the types of effects observed and in terms of the effective doses. All substances classified as reproductive toxicants by the Directive 92/32/EEC or considered as toxic to fertility by the California EPA for which we found a multi-generation study were included …..

…The second generation ….. affected neither the overall NOAEL nor the critical effect. Therefore, it had no impact on the ensuing risk assessment, nor on classification and labeling. ….

A retrospective analysis of the two-generation study: What is the added value of the second generation? G. Janers et al, (2007) Reproductive Toxicol. 24, 97

…study retrospectively evaluates 176 multi-generation studies to assess potential differences between the first and the second generation, both in terms of the types of effects observed and in terms of the effective doses. All substances classified as reproductive toxicants by the Directive 92/32/EEC or considered as toxic to fertility by the California EPA for which we found a multi-generation study were included …..

…The second generation ….. affected neither the overall NOAEL nor the critical effect. Therefore, it had no impact on the ensuing risk assessment, nor on classification and labeling. ….

A retrospective analysis of the two-generation study: What is the added value of the second generation? G. Janers et al, (2007) Reproductive Toxicol. 24, 97

…study retrospectively evaluates 176 multi-generation studies to assess potential differences between the first and the second generation, both in terms of the types of effects observed and in terms of the effective doses. All substances classified as reproductive toxicants by the Directive 92/32/EEC or considered as toxic to fertility by the California EPA for which we found a multi-generation study were included …..

…The second generation ….. affected neither the overall NOAEL nor the critical effect. Therefore, it had no impact on the ensuing risk assessment, nor on classification and labeling. ….

A retrospective analysis of the two-generation study: What is the added value of the second generation? G. Janers et al, (2007) Reproductive Toxicol. 24, 97

Methoddevelopers

Regulators

Methoddevelopers

Regulators

Catalyzers/Facilitators

Methoddevelopers

Regulators

Catalyzers/Facilitators(ECVAM)

The validation dilemma:

Are we going to hit?

Real human safety profile

The human safety profile

Tuning a test

Real human safety profile

Any model of human safety

Real human safety profile

Real world scenarios:- Inexact science- poor human data

Accuracy and errors

Animal data

Human data

Real human safety profile

Correlations?

Accuracy and errors

Real human safety profile

Correlations? False positive

False negative

Accurate

Animal models of human safety

Animal data

Real human safety profile

Real world scenarios!

Correlation of models of human safety

Animal data

Real human safety profile

Alternative data

Real world scenarios!

Correlation of models of human safety

Animal data

Real human safety profile

Alternative data

Comparison to in vitro data

Model correlation

Real human safety profile

Examples from ECVAM/NICEATM study

corr. = 0.53

correlation = 0.56

correlation = 0.62

Personal communication T. Hartung; n = 45

One step further..................

Coverage of complex toxicity by integrated test batteries (e.g developmental toxicity)

Integrated test batteries

Real human safety profile

Reproductivetoxicity

spermatogenesis

2-Generation study

Integrated test batteries

Real human safety profile

Validation procedure and regulatory acceptance

Early collaboration/contact of producer (test developer) and customer (regulator)

Agreement on relevant reference points

- Gold standard

- Reference data base

- Reference compound base

- State of the art of method and competitors

- Situation in other sectors and countries

- Buildup of experience how to interpret data; how to deal with data, historic feedback

Biological systemExposure situationModel endpointPrediction model

Test Validated Test

AppliedTest

Regulator input: tuning

Regulator input: fine-tuning/post-validation

- Continuous feedback in test pipeline

Validation procedure and regulatory acceptance

University Konstanz

Doerenkamp-ZbindenFoundation