New Approach Methodologies (NAMs) In Next-Generation Risk Assessment (NGRA): Transforming Human Health Safety Evaluation

Traditional toxicological risk assessment has long relied on laboratory animal studies to derive a Point of Departure (PoD), such as a No-Observed-Adverse-Effect Level (NOAEL) or Lowest-Observed-Adverse-Effect Level (LOAEL). These values are extrapolated to humans using uncertainty factors to establish health-based guidance values, including Derived No-Effect Levels (DNELs) or Tolerable Intakes (TIs). External human exposure is then compared against these thresholds to calculate a margin of safety. 

While this paradigm has supported chemical regulation for decades, it introduces substantial uncertainty related to species differences, exposure routes, dose duration, and mechanistic relevance. These limitations have accelerated global regulatory and scientific interest in New Approach Methodologies (NAMs) and their application within Next-Generation Risk Assessment (NGRA) frameworks. 

At Maven Regulatory Solutions, we closely track and apply NAM-driven strategies to support regulatory-ready, human-relevant chemical safety assessments aligned with evolving EU, UK, and global regulatory expectations. 

What Are NAMs and Why They Matter for NGRA? 

New Approach Methodologies (NAMs) are non-animal, mechanism-based test systems designed to evaluate chemical hazards using human-relevant biological models. NAMs focus on perturbations of key toxicity pathways rather than apical endpoints observed in animal studies. 

In an NGRA framework, PoDs derived from NAMs are compared against estimated internal human exposures (e.g., plasma or tissue concentrations), enabling biologically anchored risk characterisation with reduced uncertainty. 

Key Advantages of NAM-Based NGRA 

• Improved human relevance 
• Alignment with 3Rs principles (Replacement, Reduction, Refinement) 
• Mechanistic insight into mode of action 
• Support for animal-free regulatory strategies 
• Faster, scalable screening across large chemical inventories 

NAM Platforms Supporting Human Health NGRA 

1. ToxTracker® – Mechanistic Genotoxicity & Carcinogenicity Screening 

ToxTracker is a validated NAM that uses mouse embryonic stem cell lines engineered with fluorescent reporters to detect activation of pathways associated with carcinogenesis. 

Biological Responses Assessed: 

• Cytotoxicity 
• DNA damage 
• Oxidative stress 
• Protein damage 

Cells are exposed with and without metabolic activation (S9) and increases in Green Fluorescent Protein (GFP) expression are quantified. 

Key Outputs (PoDs): 

• NOEL / LOEL 
• NOGEL / LOGEL 

ToxTracker enables mechanistic differentiation between direct genotoxicity and secondary stress responses critical for NGRA decision-making. 

2. High-Throughput Transcriptomics (HTTr) 

HTTr evaluates global gene expression changes using human cell models such as HepG2, HepaRG, or MCF-7 cells. 

A global Point of Departure is derived from the most sensitive transcriptomic response, producing a: 

• No-Observed-Transcriptional-Effect Level (NOTEL) 

This NOTEL represents the lowest concentration inducing molecular perturbation, making HTTr highly valuable for early-tier NGRA screening and chemical prioritisation. 

 3. Cell Stress Panel – Integrated Cellular Health Assessment 

The Cell Stress Panel monitors biomarkers across multiple cellular stress pathways, including: 

• Mitochondrial dysfunction 
• Oxidative stress 
• Cell viability and integrity 

Data from multiple assays are integrated using concentration-response modelling to derive: 

• Individual assay PoDs 
• A global PoD representing the minimum effect concentration 

This approach supports systemic toxicity evaluation without reliance on animal testing. 

4. In Vitro Pharmaceutical Profiling (IPP) 

IPP is widely used in early pharmaceutical and chemical safety screening to identify molecular interactions that may result in adverse drug reactions (ADRs) or off-target toxicity. 

Key Features: 

• Screening against ~73 biological targets 
• GPCRs, ion channels, enzymes, transporters 
• Binding and functional assays 

Decision Criteria: 

• EC?? or LC?? responses >50% indicate biologically significant interactions 

IPP supports organ-specific hazard identification and informs follow-up NAM selection. 

5. CALUX® Bioassays – Pathway Confirmation 

CALUX assays use human U2-OS cell lines containing luciferase reporter genes linked to specific signalling pathways. 

CALUX is particularly useful as a follow-up to IPP positives, confirming whether receptor binding results in functional pathway activation. 

Key PoDs: 

• Lowest-Effect Concentration (LEC) 
• PC?? (50% pathway activation) 

6. ReproTracker® 2.0 – Developmental Toxicity NAM 

ReproTracker 2.0 focuses on developmental and reproductive toxicity by measuring disruption of stem cell differentiation into: 

• Cardiac 
• Neural 
• Hepatic lineages 

Significant biomarker perturbation leads to classification of a compound as a potential teratogen, supporting NGRA without animal embryo testing. 

7. DevTox QuickPredict™ – Human Embryonic Stem Cell Assay 

This assay evaluates changes in ornithine and cysteine metabolism, key pathways in early embryonic development. 

Results are expressed as an o/c ratio, plotted in a metabolic response curve to predict: 

• Developmental toxicity 
• General cytotoxicity 

8. Zebrafish Developmental Toxicity Assay 

Although not fully animal-free, the zebrafish assay provides vertebrate developmental insights with strong translational relevance. 

Key Endpoints: 

• Morphological abnormalities 
• Mortality 
• EC?? / LC?? ratios 

A Tolerable Intake (TI) ≥2 indicates teratogenic potential, enabling comparison with mammalian toxicity data. 

Comparative Overview of NAM Applications 

Regulatory Outlook: NAMs in Chemical Risk Assessment 

Running a full NAM battery across all systemic endpoints remains resource intensive. As such, regulators are not yet adopting NGRA as a complete replacement for animal-based risk assessment. 

However, ECHA, OECD, and EU institutions are actively advancing NAM integration through: 

• Targeted regulatory pilots 
• Stakeholder workshops 
• Chemical prioritisation programs 

NAMs are increasingly accepted for: 

• Screening and prioritisation 
• Weight-of-Evidence support 
• Data gap filling 
• Read-across justification 

How Maven Regulatory Solutions Supports NAM-Driven NGRA 

Maven Regulatory Solutions provides strategic and scientific expertise across: 

• NAM selection and study design 
• NGRA workflow development 
• PoD derivation and internal exposure modelling 
• Regulatory-ready Weight-of-Evidence integration 
• EU REACH, UK, and global compliance alignment 

We bridge cutting-edge toxicology with regulatory practicality. 

Frequently Asked Questions (FAQ) 

Are NAMs accepted by regulators today? 
Yes, primarily as part of Weight-of-Evidence and prioritisation strategies. 

Do NAMs replace animal studies entirely? 
Not yet, but they increasingly reduce animal testing requirements. 

Are NAMs suitable for REACH and occupational safety? 
Yes, particularly within NGRA and read-across frameworks. 

Do NAMs improve human relevance? 
Significantly, especially when internal exposure metrics are used. 

Conclusion: NAMs as the Foundation of Future Chemical Safety 

NAMs are redefining how chemical hazards are identified, understood, and managed. While challenges remain, their integration into Next-Generation Risk Assessment represents a decisive shift toward mechanistic, human-relevant, and sustainable toxicology. 

Companies that invest early in NAM-driven strategies will be best positioned for future regulatory frameworks. 

Maven Regulatory Solutions is your partner in navigating this transformation.