Implementing a globally harmonized risk assessment-based approach for regulatory decision-making of crop protection products

Exposure considerations in human safety assessment: Report from an EPAA Partners' Forum

Understanding and estimating the exposure to a substance is one of the fundamental requirements for safe manufacture and use. Many approaches are taken to determine exposure to substances, mainly driven by potential use and regulatory need. There are many opportunities to improve and optimise the use of exposure information for chemical safety. The European Partnership for Alternative Approaches to Animal Testing (EPAA) therefore convened a Partners' Forum (PF) to explore exposure considerations in human safety assessment of industrial products to agree key conclusions for the regulatory acceptance of exposure assessment approaches and priority areas for further research investment. The PF recognised the widescale use of exposure information across industrial sectors with the possibilities of creating synergies between different sectors. Further, the PF acknowledged that the EPAA could make a significant contribution to promote the use of exposure data in human safety assessment, with an aim to address specific regulatory needs. To achieve this, research needs, as well as synergies and areas for potential collaboration across sectors, were identified.

A perspective on In vitro developmental neurotoxicity test assay results: An expert panel review

For decades, there has been increasing concern about the potential developmental neurotoxicity (DNT) associated with chemicals. Regulatory agencies have historically utilized standardized in vivo testing to evaluate DNT. Owing to considerations including higher-throughput screening for DNT, reduction in animal use, and potential cost efficiencies, the development of alternative new approach methods (NAMs) occurred; specifically, the advent of the DNT in vitro test battery (DNT IVB). SciPinion convened an expert panel to address specific questions related to the interpretation of in vitro DNT test data. The consensus of the expert panel was that the DNT IVB might be used during initial screening, but it is not presently a complete or surrogate approach to determine whether a chemical is a DNT in humans. By itself, the DNT IVB does not have the ability to capture nuances and complexity of the developing nervous system and associated outcomes including behavioral ontogeny, motor activity, sensory function, and learning/memory. Presently, such developmental landmarks cannot be adequately assessed in the DNT IVB or by other NAMs. The expert panel (all who serve as co-authors of this review) recommended that additional data generation and validation is required before the DNT IVB can be considered for application within global regulatory frameworks for decision-making.

Transforming the evaluation of agrochemicals

The present agrochemical safety evaluation paradigm is long-standing and anchored in well-established testing and evaluation procedures. However, it does not meet the present-day challenges of rapidly growing populations, food insecurity, and pressures from climate change. To transform the current framework and apply modern evaluation strategies that better support sustainable agriculture, the Health and Environmental Sciences Institute (HESI) assembled a technical committee to reframe the safety evaluation of crop-protection products. The committee is composed of international experts from regulatory agencies, academia, industry and nongovernmental organizations. Their mission is to establish a framework that supports the development of fit-for-purpose agrochemical safety evaluation that is applicable to changing global, as well as local needs and regulatory decisions, and incorporates relevant evolving science. This will be accomplished through the integration of state-of-the-art scientific methods, technologies and data sources, to inform safety and risk decisions, and adapt them to evolving local and global needs. The project team will use a systems-thinking approach to develop the tools that will implement a problem formulation and exposure driven approach to create sustainable, safe and effective crop protection products, and reduce, replace and refine animal studies with fit-for-purpose assays. A new approach necessarily will integrate the most modern tools and latest advances in chemical testing methods to guarantee the robust human and environmental safety and risk assessment of agrochemicals. This article summarizes the challenges associated with the modernization of agrochemical safety evaluation, proposes a potential roadmap, and seeks input and engagement from the broader community to advance this effort. © 2022 Health and Environmental Sciences Institute (HESI). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

EU’s next generation risk assessment: hurdles and opportunities for new approach methodologies

The EU’s decision to ban animal testing for toxicity testing, has positively influenced the pace of developing New Approach Methodologies (NAMs). This development also supports replacing animal methods in other forms of risk assessment (RA), such as for oral-toxicity testing. This study aims to identify the hurdles and opportunities for validation and implementation of NAMs in the current EU’s chemical RA. Through conducting semi-structured interviews with 14 stakeholders, experiences and perspectives about the validation and implementation of NAMs in RA for orally ingested chemicals were analyzed. Stakeholders considered the use of NAMs for RA processes both a cultural and generational issue. Both were perceived as hurdles for reaching the next generation RA approach. The differing views on NAMs originated from experience and stakeholder positions, but communication and collaboration on developing future RA approaches could support overcoming this skepticism. Irrespectively of their background, all interviewees were generally optimistic that NAMs will support the development of more accurate and sustainable RA. This research highlights the need for the EU to adjust legislation and guidance documents to shift in testing requirements from the traditional overexposure approach to more predictive, mechanistic testing in RA, which will take time. This study, however, shows that—when all stakeholders engage in communication and confidence building—NAMs can already play an important role in reducing and refining animal testing.

Using existing knowledge for the risk evaluation of crop protection products in order to guide exposure driven data generation strategies and minimise unnecessary animal testing

Traditionally, human health risk assessment focuses on defining the hazard through mammalian toxicity studies followed by exposure estimation. We have explored ways of predicting exposure based primarily on the use scenario and comparing the exposure to reference dose values derived by various regulatory agencies (US EPA, JMPR, and EU Commission) in order to identify mammalian toxicity studies that are relevant to human health risk assessment. Human dietary exposure was based on existing residue data for substances with comparable use on the same or similar crops. Human occupational exposures were based on the use scenarios and application methods. To provide a point of comparison for the exposure predictions, data were collated for acute, chronic and occupational reference dose values derived by various regulatory agencies (US EPA, JMPR, and EU Commission). The exposure predictions and range of hazard endpoints were compared using the ILSI HESI Risk21 risk matrix plots in order to visualise and contextualise the level of potential concern for the exposure prediction. In addition, an approach is proposed to categorise the likelihood of acceptability of risk based on where the exposure sits relative to the distribution of reference dose values. The approaches proposed in this study allow for exposure prediction based on the Good Agricultural Practice (GAP) in conjunction with the use of existing hazard data for crop protection products in order to make an initial determination on acceptability of risk and to identify key studies that are required for human health risk assessment and also opportunities for study waivers.

Rethinking agrochemical safety assessment: A perspective

Agrochemical safety assessment has traditionally relied on the use of animals for toxicity testing, based on scientific understanding and test guidelines developed in the 1980s. However, since then, there have been significant advances in the toxicological sciences that have improved our understanding of mechanisms underpinning adverse human health effects. The time is ripe to 'rethink' approaches used for human safety assessments of agrochemicals to ensure they reflect current scientific understanding and increasingly embrace new opportunities to improve human relevance and predictivity, and to reduce the reliance on animals. Although the ultimate aim is to enable a paradigm shift and an overhaul of global regulatory data requirements, there is much that can be done now to ensure new opportunities and approaches are adopted and implemented within the current regulatory frameworks. This commentary reviews current initiatives and emerging opportunities to embrace new approaches to improve agrochemical safety assessment for humans, and considers various endpoints and initiatives (including acute toxicity, repeat dose toxicity studies, carcinogenicity, developmental and reproductive toxicity, exposure-driven approaches, inhalation toxicity, and data modelling). Realistic aspirations to improve safety assessment, incorporate new technologies and reduce reliance on animal testing without compromising protection goals are discussed.