An Integrated European ‘Flagship’ Program Driving Mechanism-based Toxicity Testing and Risk Assessment for the 21st Century

The vision of EU-ToxRisk is to drive a paradigm shift in toxicology towards an animal-free, mechanism-based integrated approach to chemical safety assessment. The project will unite all relevant disciplines and stakeholders
to establish: i) pragmatic, solid read-across procedures incorporating mechanistic and toxicokinetic knowledge; and ii) ab initio hazard and risk assessment strategies of chemicals with little background information. The project will focus on repeated dose systemic toxicity (liver, kidney, lung and nervous system) as well as developmental/ reproduction toxicity. Different human tiered test systems are integrated to balance speed, cost and biological
complexity. EU-ToxRisk extensively integrates the adverse outcome pathway (AOP)-based toxicity testing concept. Therefore, advanced technologies, including high throughput transcriptomics, RNA interference, and high throughput microscopy, will provide quantitative and mechanistic underpinning of AOPs and key events (KE). The project combines in silico tools and in vitro assays by computational modelling approaches to provide quantitative data
on the activation of KE of AOP. This information, together with detailed toxicokinetics data, and in vitro-in vivo extrapolation algorithms forms the basis for improved hazard and risk assessment. The EU-ToxRisk work plan is
structured along a broad spectrum of case studies, driven by the cosmetics, (agro)-chemical, pharma industry together with regulators. The approach involves iterative training, testing, optimization and validation phases to establish fitfor-purpose integrated approaches to testing and assessment with key EU-ToxRisk methodologies. The test systems will be combined to a flexible service package for exploitation and continued impact across industry sectors and regulatory application. The proof-of-concept for the new mechanism-based testing strategy will make EU-ToxRisk the flagship in Europe for animal-free chemical safety assessment.