Scientific Opinion of the Scientific Panel on Plant Protection Products and their Residues (PPR Panel) on testing and interpretation of comparative in vitro metabolism studies

Updated peer review of the pesticide risk assessment of the active substance spinosad

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, the Netherlands, and co-rapporteur Member State, France, for the pesticide active substance spinosad and the assessment of applications for maximum residue levels (MRLs) are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012. The conclusions were reached on the basis of the evaluation of the representative uses of spinosad as insecticide on bulb/dry onions, maize (fodder and grain), sweet corn, grapes (table and wine), lettuce, potato, aubergine, pepper and tomato. MRLs were assessed in field leek and field and greenhouse strawberries, cane fruits, lettuce & plants salad (others), spinach and similar leaves (others), herbs and edible flowers (others), cardoons, rhubarb and animal commodities. The conclusions from 2018 were updated in 2024 following the request from the European Commission with regard to the endocrine-disrupting properties. The reliable end points, appropriate for use in regulatory risk assessment and the proposed MRLs, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

Guidance on the scientific requirements for an application for authorisation of a novel food in the context of Regulation (EU) 2015/2283

The European Commission requested EFSA to update the scientific guidance for the preparation of applications for authorisation of novel foods, previously developed following the adoption of Regulation (EU) 2015/2283 on novel foods. This guidance document provides advice on the scientific information needed to be submitted by the applicant towards demonstrating the safety of the novel food. Requirements pertain to the description of the novel food, production process, compositional data, specifications, proposed uses and use levels and anticipated intake of the novel food. Furthermore, information needed in sections on the history of use of the novel food and/or its source, absorption, distribution, metabolism, excretion, toxicological information, nutritional information and allergenicity is also described. The applicant should integrate and interpret the data presented in the different sections to provide their overall considerations on how the information supports the safety of the novel food under the proposed conditions of use. Where potential health hazards have been identified, they are to be discussed in relation to the anticipated intake of the novel food and the proposed target populations. On the basis of the information provided, EFSA will assess the safety of the novel food under the proposed conditions of use.

Stem cell-based approaches for developmental neurotoxicity testing

Neurotoxicants are substances that can lead to adverse structural or functional effects on the nervous system. These can be chemical, biological, or physical agents that can cross the blood brain barrier to damage neurons or interfere with complex interactions between the nervous system and other organs. With concerns regarding social policy, public health, and medicine, there is a need to ensure rigorous testing for neurotoxicity. While the most common neurotoxicity tests involve using animal models, a shift towards stem cell-based platforms can potentially provide a more biologically accurate alternative in both clinical and pharmaceutical research. With this in mind, the objective of this article is to review both current technologies and recent advancements in evaluating neurotoxicants using stem cell-based approaches, with an emphasis on developmental neurotoxicants (DNTs) as these have the most potential to lead to irreversible critical damage on brain function. In the next section, attempts to develop novel predictive model approaches for the study of both neural cell fate and developmental neurotoxicity are discussed. Finally, this article concludes with a discussion of the future use of in silico methods within developmental neurotoxicity testing, and the role of regulatory bodies in promoting advancements within the space.

Fecal elimination of fluralaner in different carnivore species after oral administration

Fluralaner is a recent external parasiticide, first of a new class of drugs (isoxazoline parasiticides). It is widely used in companion animals both for its wide spectrum (fleas, ticks and other mites) but also for its ease of use (oral tablets given once for 1 to three months). It is known to be eliminated primarily via the feces (>90%) as the unchanged compound. In zoo carnivores, controlling external parasites is also important and there are no specific products with a marketing authorization to control them. The first objective of this study was to evaluate the pharmacokinetic profile of fluralaner in zoo carnivores. The second objective was to demonstrate that fluralaner can be eliminated over a prolonged period of time, thereby raising questions about its potential impact on non-target species such as arthropods. After adjusting the oral dose using allometric equations, animals were dosed and fecal samples were collected on a regular basis for up to three months to determine the fecal elimination curve of fluralaner as a surrogate of plasma kinetics (for ethical and safety reasons, plasma samples were not considered). All samples were analyzed with a validated LC-MSMS technique. Our results show that, despite limitations and a limited number of animals included, most carnivores eliminate fluralaner in their feces for several weeks to months (in Lions, fluralaner was still detectable after 89 days). To our knowledge, this is the first study demonstrating such a long elimination period in animals. Further studies would be required to investigate the risk associated with the presence of active residues in other carnivore feces for the environment, especially in dogs and cats, considering the large use of this class of compounds.

Systematic approaches to machine learning models for predicting pesticide toxicity

Pesticides play an important role in modern agriculture by protecting crops from pests and diseases. However, the negative consequences of pesticides, such as environmental contamination and adverse effects on human and ecological health, underscore the importance of accurate toxicity predictions. To address this issue, artificial intelligence models have emerged as valuable methods for predicting the toxicity of organic compounds. In this review article, we explore the application of machine learning (ML) for pesticide toxicity prediction. This review provides a detailed summary of recent developments, prediction models, and datasets used for pesticide toxicity prediction. In this analysis, we compared the results of several algorithms that predict the harmfulness of various classes of pesticides. Furthermore, this review article identified emerging trends and areas for future direction, showcasing the transformative potential of machine learning in promoting safer pesticide usage and sustainable agriculture.

Metabolites in the regulatory risk assessment of pesticides in the EU

A large majority of chemicals is converted into metabolites through xenobiotic-metabolising enzymes. Metabolites may present a spectrum of characteristics varying from similar to vastly different compared with the parent compound in terms of both toxicokinetics and toxicodynamics. In the pesticide arena, the role of metabolism and metabolites is increasingly recognised as a significant factor particularly for the design and interpretation of mammalian toxicological studies and in the toxicity assessment of pesticide/metabolite-associated issues for hazard characterization and risk assessment purposes, including the role of metabolites as parts in various residues in ecotoxicological adversities. This is of particular relevance to pesticide metabolites that are unique to humans in comparison with metabolites found in in vitro or in vivo animal studies, but also to disproportionate metabolites (quantitative differences) between humans and mammalian species. Presence of unique or disproportionate metabolites may underlie potential toxicological concerns. This review aims to present the current state-of-the-art of comparative metabolism and metabolites in pesticide research for hazard and risk assessment, including One Health perspectives, and future research needs based on the experiences gained at the European Food Safety Authority.

TKPlate 1.0: An Open-access platform for toxicokinetic and toxicodynamic modelling of chemicals to implement new approach methodologies in chemical risk assessment

This publication is linked to the following EFSA Supporting Publications articles: http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2023.EN-8441/full, http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2023.EN-8440/full, http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2023.EN-8437/full.

Is the 90-day dog study necessary for pesticide toxicity testing?

When registering a new pesticide, 90-day oral toxicity studies performed with both rodent and non-rodent species, typically rats and dogs, are part of a standard battery of animal tests required in most countries for human health risk assessment (RA). This analysis set out to determine the need for the 90-day dog study in RA by reviewing data from 195 pesticides evaluated by the US Environmental Protection Agency (USEPA) from 1998 through 2021. The dog study was used in RA for only 42 pesticides, mostly to set the point of departure (POD) for shorter-term non-dietary pesticide exposures. Dog no-observed-adverse-effect-levels (NOAELs) were lower than rat NOAELs in 90-day studies for 36 of the above 42 pesticides, suggesting that the dog was the more sensitive species. However, lower NOAELs may not necessarily correspond to greater sensitivity as factors such as dose spacing and/or allometric scaling need to be considered. Normalizing doses between rats and dogs explained the lower NOAELs in 22/36 pesticides, indicating that in those cases the dog was not more sensitive, and the comparable rat study could have been used instead for RA. For five of the remaining pesticides, other studies of appropriate duration besides the 90-day rat study were available that would have offered a similar level of protection if used to set PODs. In only nine cases could no alternative be found in the pesticide's database to use in place of the 90-day dog study for setting safe exposure levels or to identify unique hazards. The present analysis demonstrates that for most pesticide risk determinations the 90-day dog study provided no benefit beyond the rat or other available data.

Candidate Proficiency Test Chemicals to Address Industrial Chemical Applicability Domains for in vitro Human Cytochrome P450 Enzyme Induction

Cytochrome P450 (CYP) enzymes play a key role in the metabolism of both xenobiotics and endogenous chemicals, and the activity of some CYP isoforms are susceptible to induction and/or inhibition by certain chemicals. As CYP induction/inhibition can bring about significant alterations in the level of in vivo exposure to CYP substrates and metabolites, CYP induction/inhibition data is needed for regulatory chemical toxicity hazard assessment. On the basis of available human in vivo pharmaceutical data, a draft Organisation for Economic Co-operation and Development Test Guideline (TG) for an in vitro CYP HepaRG test method that is capable of detecting the induction of four human CYPs (CYP1A1/1A2, 2B6, and 3A4), has been developed and validated for a set of pharmaceutical proficiency chemicals. However to support TG adoption, further validation data was requested to demonstrate the ability of the test method to also accurately detect CYP induction mediated by industrial and pesticidal chemicals, together with an indication on regulatory uses of the test method. As part of "GOLIATH", a European Union Horizon-2020 funded research project on metabolic disrupting chemical testing approaches, work is underway to generate supplemental validated data for an additional set of chemicals with sufficient diversity to allow for the approval of the guideline. Here we report on the process of proficiency chemical selection based on a targeted literature review, the selection criteria and considerations required for acceptance of proficiency chemical selection for OECD TG development (i.e. structural diversity, range of activity, relevant chemical sectors, global restrictions etc). The following 13 proposed proficiency chemicals were reviewed and selected as a suitable set for use in the additional validation experiments: tebuconazole, benfuracarb, atrazine, cypermethrin, chlorpyrifos, perfluorooctanoic acid, bisphenol A, N,N-diethyl-m-toluamide, benzo-[a]-pyrene, fludioxonil, malathion, triclosan, and caffeine. Illustrations of applications of the test method in relation to endocrine disruption and non-genotoxic carcinogenicity are provided.