Non-testing approaches under REACH--help or hindrance? Perspectives from a practitioner within industry

Legislation such as REACH strongly advocates the use of alternative approaches including in vitro, (Q)SARs, and chemical categories as a means to satisfy the information requirements for risk assessment. One of the most promising alternative approaches is that of chemical categories, where the underlying hypothesis is that the compounds within the category are similar and therefore should have similar biological activities. The challenge lies in characterizing the chemicals, understanding the mode/mechanism of action for the activity of interest and deriving a way of relating these together to form inferences about the likely activity outcomes. (Q)SARs are underpinned by the same hypothesis but are packaged in a more formalized manner. Since the publication of the White Paper for REACH, there have been a number of efforts aimed at developing tools, approaches and techniques for (Q)SARs and read-across for regulatory purposes. While technical guidance is available, there still remains little practical guidance about how these approaches can or should be applied in either the evaluation of existing (Q)SARs or in the formation of robust categories. Here we provide a perspective of how some of these approaches have been utilized to address our in-house REACH requirements.