S5: OECD Harmonised Template 201

OECD Harmonised Template 201 – the missing link between AOP science and regulatory acceptance


Clemens Wittwehr




The basic information most current animal tests deliver is how much of a chemical substance has to be applied for how long to a test animal to trigger an adverse effect like cancer, reproductive issues, other effects, or simply mortality. Not only are in vivo animal tests unethical and expensive, they also fail to answer the fundamental question:

"How does a chemical actually work when it leads to an adverse outcome?"

In other words: How does a chemical effect cell biology, or how does it interfere with normal physiology leading to an adverse outcome?

With an answer to this question, science could develop predictive models to foresee the toxic effects of a chemical, derived from observations in test systems that are based on molecular, cellular, or tissue/organ level - before the actual negative outcome manifests itself in a living organism.

If researchers could capture these test observations in a coherent, widely accepted data format (comparable and compatible to the data formats already used today), the results would be used by modellers to build and calibrate their predictive systems, which in turn could be applied to yet untested chemicals to further reduce testing.

Such a new data format template has been developed by the European Commission's Joint Research Centre (JRC), in collaboration with ECHA and the OECD, which had already designed and published several other OECD Harmonised Templates (OHTs) to report test results concerning physical/chemical properties, human toxicity and environmental toxicity.

While these templates are geared towards results derived from classical (mostly OECD guideline) studies, focusing on apical endpoints, the new template is now the emerging standard for reporting "Intermediate Effects", i.e. observations relevant in the description and ultimately prediction of toxicity.

The presentation will highlight the main elements of this new template ("OHT 201"), the way to populate it and an outlook on what strategy OECD will follow when promoting it.