Validation of the Epi2SensA Method Using the EpiDerm™ Model for Skin Sensitization Testing Under OECD TG442D

Area of Science:

• Toxicology
• In vitro testing
• Dermatology

Background:

• Assessing chemical skin sensitization is crucial for public health and regulatory compliance.
• Existing methods like EpiSensA are validated but may benefit from alternative reconstructed human epidermis (RhE) models.
• The EpiDerm™ model offers a potential alternative for skin sensitization testing.

Purpose of the Study:

• To evaluate the Epi2SensA method using the EpiDerm™ RhE model for chemical skin sensitization assessment.
• To determine the reliability and predictive capacity of Epi2SensA according to OECD Performance Standards.
• To compare the performance of Epi2SensA with the established EpiSensA assay.

Main Methods:

• An interlaboratory validation study was conducted involving four laboratories.
• Twenty coded reference substances with varying sensitization potentials were tested under blinded conditions.
• Modified acceptance criteria and a prediction model were applied for statistical analysis.

Main Results:

• The Epi2SensA method achieved high between-laboratory reproducibility (85%) and within-laboratory reproducibility (83.3%).
• Predictivity parameters demonstrated strong performance: 88.1% sensitivity, 88.9% specificity, and 88.3% accuracy.
• Performance metrics were comparable to the validated EpiSensA reference method.

Conclusions:

• The Epi2SensA assay using the EpiDerm™ model is a reliable and predictive method for assessing skin sensitization potential.
• The adapted protocol and modified statistical analysis improved the assay's performance.
• Epi2SensA shows promise for regulatory acceptance as an alternative to current OECD TG 442D testing methods.