How to submit a successful Read Across justification report

This virtual meeting will include a perspective by Costanza Rovida (Scientific Officer and Senior Regulatory Specialist, CAAT) followed by a discussion session.

Read-across (RAx) is probably the most used strategy to waive new demanding in vivo tests for toxicological assessment of chemicals. It is based on the possibility to translate available information from well-characterized chemicals (source) to the substance for which there is a toxicological data gap (target). In spite of the widespread use, regulatory acceptance is still limited, and the main reason could be a superficial approach to the problem or just an unsatisfactory content of the justification report.

Three major issues were identified that need optimization, in order to allow for a higher regulatory acceptance rate of the RAx procedure: (i) the definition of similarity of source and target, (ii) the translation of biological/toxicological activity of source to target, in the RAx procedure, and (iii) how to deal with issues of ADME that may differ between source and target. New Approach Methods (NAM) may be used to confirm chemical and toxicological similarities and to contribute to the reduction of the uncertainty. In general, Good Read-Across Practice (GRAP) can guide on best practices to perform and evaluate the RAx process as well as to prepare a suitable report.