Using Mode of Action Information to Improve Regulatory Decision Making

Introduction

A workshop entitled “Using mode of action information to improve regulatory decision making' was held 2-3 November at the City Presentation Centre in London. This event was organised in co-operation with HESI, and was sponsored by Cefic LRI.

The main goal of the meeting was to examine to what extent toxicological mode of action information can be used to modify human risk assessment. This approach evaluates the known key steps in the toxicological mode of action in animals with the available information on the relevance of this pathway in man.

The discussion centred on the “mode of action framework' which is promoted by the WHO International Programme on Chemical Safety (IPCS) and is similar to the approach proposed by ECETOC in Technical Report 99 - “Toxicological modes of action: relevance for human risk assessment' which was published in 2006.

Presentations were made by a distinguished group of speakers from academia and industry, which used case studies to illustrate the practical use of the framework.

Conclusions and recommendations

There was a high level of agreement on using this approach where sufficient information is available to characterise a “mode of action'. There was of course some debate as to how much data would be needed to establish a “known mode of action', which could then be extrapolated from one example to less thoroughly investigated chemicals. One of the main recommendations of this meeting was the establishment of a register of those modes of action which are sufficiently well described as to be useful in employing this approach in risk assessment within a regulatory context.