New OECD IATA case studies illustrate frameworks for chemical safety assessment

The Organisation for Economic Co-operation and Development (OECD) has released two Integrated Approaches to Testing and Assessment (IATA) case studies as part of its tenth review cycle, coordinated under the Working Party on Hazard Assessment (WPHA). These case studies examine innovative methodologies for chemical safety assessment in regulatory contexts, highlighting their practical implementation and relevance. By showcasing IATA frameworks that could be reused and adapted, the studies promote more efficient, consistent, and transparent regulatory decision-making. Agreeing on and disseminating structured, evidence-based approaches may lay the groundwork for future Defined Approaches (DAs), supporting evolution toward more standardised and mechanistic safety assessment strategies.

• OECD Series on Testing and Assessment No. 410: Case study on the use of IATA for prioritisation of chemicals using the IATA-based Ecological Risk Classification (ERC) approach, Version 2: ERC2, released by Environment and Climate Change Canada in 2022, uses a weight-of-evidence framework that assesses the risk of organic chemicals by integrating existing data and filling gaps with in silico tools. Multiple endpoints are evaluated using standardised criteria to enhance clarity, confidence, and reduce uncertainty. A case study of 24 diverse chemicals and a single-substance example illustrates its practical application and methodology.

• OECD Series on Testing and Assessment No. 415: Case studies for the IATA in the application of combined bioinformatics approaches for cross species extrapolation of toxicity knowledge to inform chemical safety: This IATA incorporates advanced bioinformatics tools—Genes-to-Pathways Species Conservation Analysis (G2P-SCAN) and Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS)—alongside curated databases to evaluate conserved biological features at the DNA, RNA, and protein levels. By enabling cross-species extrapolation of toxicological effects, this approach supports science-based regulatory decision-making and strengthens ecological risk assessments by leveraging mechanistic data and addressing key data gaps. While the current focus is on demonstrating the utility of bioinformatics for assessing biological pathway conservation, the IATA is designed as a flexible framework that can be expanded to integrate additional methodologies, including those addressing toxicokinetic and broader toxicodynamic factors influencing species susceptibility.

For more information, please refer to the OECD webpage on Integrated Approaches to Testing and Assessment (IATA).