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.
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).
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.
For regulatory submission — Defined Approaches OECD TG 497
Swipe left to view all table columns →
| Objectives | Material attributes | Recommended assays |
|---|---|---|
| Hazard identification — 2o3 DA | Neat chemicals without challenging properties | DPRA (OECD 442C) + GARD®skin (OECD 442E) |
| Hazard identification — 2o3 DA | Difficult-to-test substances | EpiSensA (OECD 442D) + GARD®skin (OECD 442E) |
| Potency sub-categorization (GHS 1A/1B) — ITS | Neat chemicals without challenging properties | DPRA + GARD®skin + in silico |
| Potency sub-categorization (GHS 1A/1B) — ITS | Difficult-to-test substances | ITS often not applicable → EpiSensA as weight of evidence + GARD®skin + 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 | GARD®skin (OECD 442E) |
| Hazard identification | Medical devices and solid materials | GARD®skin adapted protocols for extractables/leachables |
| Hazard + quantitative potency assessment | Substances with unknown sensitization hazard and potency | Tiered approach: GARD®skin → GARD®skin Dose-Response |
| Quantitative potency assessment | Expected sensitizers with unknown potency | GARD®skin Dose-Response |
Defined approaches in line with OECD TG 497
OECD Test Guideline 497 introduces Defined Approaches for Skin Sensitization (DASS), which combine multiple non-animal methods to predict sensitization hazard and potency classification:
- “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® 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 testing of medical device extracts, solid materials, and 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.
