Defined approaches developed by NICEATM and ICCVAM use non-animal data to predict skin sensitization hazard and potency. These approaches combine data from the in vitro direct peptide reactivity assay (DPRA), KeratinoSens assay, and human cell line activation test (h-CLAT); read-across predictions generated by the QSAR Toolbox software package; and physical properties such as relative solubility in water and organic solvents. The defined approaches were described in papers published in 2016 and 2017 (Strickland et al. 2016, Strickland et al. 2017, Zang et al. 2017).
To assess and expand the potential applicability of these defined approaches to a broader range of chemical types, ICCVAM agencies nominated over 200 chemicals for additional testing in the DPRA, KeratinoSens, and h-CLAT tests. Chemicals being tested include pesticide ingredients and formulations, industrial chemicals, and personal care product ingredients. NTP is conducting this testing, which is expected to be completed in 2020. The study data will enable NICEATM and ICCVAM to evaluate the appropriateness of defined approaches using these three in vitro methods for various regulatory applications.