Non-animal testing strategies for skin sensitization.
Ensuring regulatory compliance and confident product development decisions.
Why testing strategy matters
Selecting appropriate skin sensitization testing strategies is essential for meeting regulatory requirements and making informed decisions throughout product development.
At SenzaGen, we design customized, non-animal testing strategies aligned with OECD guidelines and adapted to your substance’s properties, ensuring high-performing, human-relevant results.
Defined approaches for skin sensitization (DASS, OECD TG 497)
OECD Test Guideline 497 introduces Defined Approaches for Skin Sensitization (DASS), which combine multiple New Approach Methodologies (NAMs) for skin sensitization hazard and potency assessment:
- “2 out of 3” Defined Approach (2o3 DA): Supports hazard identification by relying on concordant results from any two assays addressing the first three Key Events (KE1–KE3) of the skin sensitization Adverse Outcome Pathway (AOP).
- Integrated Testing Strategy (ITS): Enables potency sub-categorization using KE1 and KE3 assay data in combination with in silico information.
GARD®at the center
GARD®skin (OECD TG 442E, 497) plays a central role across these scenarios and improve the performance and extends the overall applicability of Defined Approaches for Skin Sensitization (DASS), helping to fill data gaps in regulatory skin sensitization testing.
Beyond regulatory use, GARD® stand-alone testing provides mechanistically informative data that support confident product development decisions.
Recommended testing strategies
The most appropriate testing strategy depends on both the intended use of the data and the properties of the test material:
- Testing objective: Hazard identification vs. potency sub-categorization, and whether the data are intended to support regulatory submission or product development decision-making.
- Material attributes: Solubility and hydrophobicity (e.g. Log P > 3.5); the presence of unknown or poorly characterized constituents (e.g. UVCBs); chemical classes with limited data from conventional cell-based assays (e.g. agrochemicals, metals); and the sample matrix (e.g. neat chemical, mixture, extract, or formulation).
For regulatory submission — defined approaches under OECD TG 497
Swipe left to view all table columns →
| Objectives | Material attributes | Recommended assays |
|---|---|---|
| Hazard identification — 2o3 DA | Neat chemicals without challenging properties | GARDskin + DPRA |
| Hazard identification — 2o3 DA | Difficult-to-test substances | GARDskin + ADRA or EpiSensA |
| Potency sub-categorization (GHS 1A/1B) — ITS | Neat chemicals without challenging properties | GARDskin + DPRA + in silico |
| Potency sub-categorization (GHS 1A/1B) — ITS | Difficult-to-test substances | GARDskin + ADRA + in silico |
For product development decisions — GARD® stand-alone testing
Swipe left to view all table columns →
| Objectives | Material attributes | Recommended assays |
|---|---|---|
| Hazard identification | Neat chemicals and difficult-to-test substances | GARDskin |
| Hazard identification | Medical devices and solid materials | GARDskin Medical Device |
| Hazard + quantitative potency assessment | Substances with unknown sensitization hazard and potency | Tiered approach: GARDskin → GARDskin Dose-Response |
| Quantitative potency assessment | Expected sensitizers with unknown potency | GARDskin Dose-Response |
GARD® stand-alone testing for product development
GARD®skin measures 196 biomarkers linked to multiple key events in the skin sensitization AOP, delivering human‑relevant, mechanistic insights beyond what early‑stage tests typically provide. The assay offers high performance and broad applicability, including for “difficult‑to‑test” substances outside the domains of conventional OECD in vitro methods.
Adaptations of the assay also enable (1) testing of medical device extracts, solid materials, and (2) quantitative potency assessment to support product development and risk‑management strategies.
What GARD provides:
- Mechanistic data beyond what early-stage testing typically offers.
- Broad applicability to hydrophobic substances, natural extracts, formulations, UVCBs, and more.
- Dose-Response option for quantitative potency insights.
Key benefits:
- Enable earlier decisions during candidate selection, formulation development, and risk evaluation.
- De‑risk later stages and streamline development.
- Save time and resources in the short, medium and long run.
Choosing the right strategy: 5-step guide
- Define your testing objective.
- Characterize the test substance.
- Select assays aligned to your objectives and the AOP KEs.
- Consider applicability domains.
- Use GARD to extend applicability and create a coherent, weight‑of‑evidence package where needed.
Select and build your DASS strategy:
- Key Event 1 | OECD 442C: DPRA, ADRA
- Key Event 2 | OECD 442D: EpiSensA
- Key Event 3 | OECD 442E: GARDskin
- In silico predictions*
*Service delivered by SenzaGen’s group company, ToxHub.
