Skin Sensitization: Modeling the Human Adverse Response

Unilever initiated a long-term research and capability development program in 2004 to evaluate and implement a new conceptual approach for assuring consumer safety without animal testing (Fentem et al., 2004, Westmoreland et al., 2010). Unilever’s approach for safety assessment is risk-based, meaning that all available data on a new ingredient (including predicted levels of consumer exposure during product use) are used to assess the level of risk posed by its proposed use. The scientific challenge we continue to investigate is how novel non-animal datasets (i.e., data generated using in chemico and in vitro test methods) can be applied to risk assessment decision making to replace the need for new animal test data. Within our Skin Sensitization program we have made a long-term investment to define and explore the key toxicity pathways that drive the disease process (i.e., Allergic Contact Dermatitis) in humans, as we believe this mechanistic understanding should form a sound basis for our non-animal risk assessment approach (Maxwell et al., 2008). Here we share our progress in developing a mechanisticallybased mathematical model of the induction of skin sensitization in humans.