Building confidence in skin sensitisation potency assessment using new approach methodologies: report of the 3rd EPAA Partners Forum, Brussels, 28th October 2019

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.

Weight of Evidence Approach for Skin Sensitization Potency Categorization of Fragrance Ingredients

Reliable human potency data are necessary for conducting quantitative risk assessments, as well as development and validation of new nonanimal methods for skin sensitization assessments. Previously, human skin sensitization potency of fragrance materials was derived primarily from human data or the local lymph node assay.

Derivation of the no expected sensitization induction level for dermal quantitative risk assessment of fragrance ingredients using a weight of evidence approach

Some fragrance ingredients may have the potential to induce skin sensitization in humans but can still be safely formulated into consumer products. Quantitative Risk Assessment (QRA) for dermal sensitization is required to determine safe levels at which potential skin sensitizers can be incorporated into consumer products. The no expected sensitization induction level or NESIL is the point of departure for the dermal QRA. Sensitization assessment factors are applied to the NESIL to determine acceptable exposure levels at which no skin sensitization induction would be expected in the general population. This paper details the key steps involved in deriving a weight of evidence (WoE) NESIL for a given fragrance ingredient using all existing data, including in vivo, in vitro, and in silico. Read-across can be used to derive a NESIL for a group of structurally similar materials when data are insufficient. When sufficient target and read-across data are lacking, exposure waiving threshold (the DST) may be used. We outline the process as it currently stands at the Research Institute for Fragrance Materials Inc. (RIFM) and provide examples, but it is dynamic and is bound to change with evolving science as new approach methodologies (NAMs) are actively incorporated.