The OECD Guidelines for the Testing of Chemicals are key in performing genotoxicity studies with chemicals and pharmaceuticals for regulatory submissions. Recently, several OECD Guidelines for genotoxicity testing were updated or issued, with statistical topics now being central for data evaluation. However, clear recommendations regarding design, analysis and interpretation of results are not always given for appropriate statistical evaluation of genotoxicity data. Thus, uncertainties remain, and intensive discussions motivated the foundation of the GUM working group “Statistics” in winter 2015/16. The working group comprises statisticians and genetic toxicologists from industry, contract research organizations, academia and regulatory bodies. It serves as a platform for discussing, specifying, presenting and publishing statistical methodologies and strategies considered appropriate by the working group for data analysis in genotoxicity testing.
Recently, we published statistical analyses on different aspects of historical negative controls for the “Mammalian Erythrocyte Micronucleus Test” (OECD 474). Based on a large data set of different laboratories we were able to give suggestions regarding appropriate handling strategies as well as procedures to derive reference values for this assay (Igl et al., 2019, Regul. Toxicol. Pharmacol. 102:13-22).
Our current work focuses on the “In Vivo Mammalian Alkaline Comet Assay” (OECD 489). As interdisciplinary group we take a closer look on various aspects of the statistical analysis of Comet Assay data from more than 200 experiments performed in several laboratories. We aim at giving recommendations on the choice of statistical summary measures and advice on other experimental aspects as well as improving dose-response curve estimation of compounds.
We are always happy for new participants, who are interested in statistics and who like to support and enrich our discussions. At the moment, we meet online on a regular basis to push forward our topics, and we hope that our at least yearly face-to-face meeting will again be possible in due time.