An Approach to Setting Vertebrate Animal-use Benchmarks for Agrochemical and GM Crop Testing to Facilitate Future Animal Reduction Efforts

Agrochemical active ingredients are among the most toxicologically evaluated chemical substances, and genetically modified (GM) crops must be evaluated for safety and nutritional adequacy. Traditionally, these evaluations are conducted <i>in vivo.</i> There are concerted efforts in the agrochemical sector to reduce animal testing, but there is also an emphasis on updating test guidelines and fulfilling new data package requirements, which can both result in increased animal testing. The purpose of this project was to generate benchmarks for the numbers of vertebrate animals used in: a) evaluating agrochemical pesticidal active ingredients for human health hazards; and b) assessing GM crops for safety and nutritional adequacy, based on guideline studies for data package requirements. To achieve this, guideline studies employing vertebrates, as required by regulatory bodies for developing global data packages for new active ingredients and for GM crops, were listed. These listed guideline studies were reviewed, in terms of the study details and the required animal-use, which was determined based on best testing practices. For historical animal-use benchmarking, Corteva's six most recent agrochemical pesticidal active ingredients and four most recent GM crop events were evaluated. Across the six most recently developed active ingredients, an average of approximately 10,000 mammals were used for the testing of each (range: 5500-19,000); across the four most recently developed GM crops, the average number of vertebrates similarly used for each was approximately 1200 (range: 1000-1500). Though regulatory testing requirements are likely to change with time, as new technologies become available, this project has established a theoretical minimum requirement to help drive aspirational animal reduction goals, identified regulatory challenges associated with the reduction of animal-use, and helped to refine Corteva's vertebrate animal-use tracking approaches.