COMPASS · COMPrehensive framework for dAta-driven chemical teSting Solutions

Chemical safety assessment is moving away from animal testing, but the regulatory uptake of non-animal methods (NAMs) is slowed by the lack of frameworks that connect mechanistic data to decision-making. COMPASS responds to this challenge by establishing a comprehensive, data-driven framework that connects mechanistic evidence from NAMs with Adverse Outcome Pathways (AOPs), creating a foundation for predictive, human-relevant, and cross-species safety assessment. A central aim is to enable the transparent selection of the most informative test systems and the design of minimal yet high-impact testing strategies, ensuring that complex biological mechanisms are captured. By addressing urgent regulatory needs such as lung fibrosis, highlighted in the OECD pulmonary fibrosis AOP and increasingly linked to nanomaterial exposures, the project will demonstrate how mechanistic insight can be harnessed for endpoints where current assessment tools are insufficient. Beyond this targeted case, COMPASS generalises the approach to systemic toxicity, enabling streamlined first-tier strategies that capture a broad range of mechanisms and support Safe-and-Sustainable-by-Design innovation. In doing so, the project strengthens the scientific basis of regulatory decision-making, accelerates the transition away from animal testing, and contributes to the European Green Deal’s ambition of a toxic-free environment and a globally competitive, sustainable chemical sector.