The OECD Guideline 497 on Defined Approaches for Skin Sensitisation (DASS) was adopted in 2021 as the first guideline based on Defined Approaches (DAs), which integrate multiple information sources (in vitro, in chemico and in silico) with a fixed Data Interpretation Procedure (DIP). Initially, TG 497 consisted of two chapters: the first dedicated to a DA for hazard predictions, and the second to DAs for potency predictions. With the inclusion of the SARA-ICE DA, TG 497 now features a third chapter, describing the use of a DA to derive a point of departure (PoD) for quantitative risk assessment of skin sensitisation.
The SARA-ICE DA is a model based on Bayesian statistics, which integrates multiple new approach methodologies (NAMs) to estimate a PoD. Its adoption marks an important step forward, as for the first time a Defined Approach has been formally recognised not only for hazard and potency predictions but also for quantitative risk assessment. This allows the use of NAMs to move beyond binary hazard identification and toward establishing science-based exposure limits derived entirely without animal testing.
