Swedish TV4: Watch how genomics and machine learning are replacing animal testing in chemical safety

SenzaGen joined Lund University researchers on Swedish TV4 to show how genomics- and machine learning-based methods are transforming the field — delivering faster, more accurate, and human-relevant safety assessment.

See how these approaches can protect human health, meet evolving regulatory demands, and open new opportunities in a market driven by scientific innovation and the global shift away from animal testing.

▶️ Watch interview 

SenzaGen’s Newsletter Q1 2026

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SenzaGen Newsletter Q1, 2026

SOT 2026: Advancing NAMs for skin and respiratory sensitization testing

We had a fantastic time at this year’s SOT meeting in San Diego, connecting with peers, exploring new ideas, and sharing the latest GARD® data on skin and respiratory sensitization from our industry collaborations. Thank you to all our collaborative partners for the outstanding teamwork!

Bayer | Coty | ExxonMobil | GDIT | Haleon | J&J MedTech | Merck

GARD for assessing biopesticides and complex mixtures

Dr Andy Forreryd and Dr Tim Lindberg of SenzaGen presented at SOT symposium sessions, demonstrating how GARD® supports sensitization assessment of biopesticides and complex mixtures.

Respiratory sensitization, protein allergy and medical devices

At SenzaGen’s hosted session, guest speakers from Merck, GDIT, and J&J MedTech shared new GARD® data on respiratory sensitization and ISO 10993-10 compliance for medical devices.

New scientific publication: Quantitative risk assessment of fragrance materials using NAMs

The collaborative work within the International Dialogue for the Evaluation of Allergens (IDEA) has been recently published in Regulatory Toxicology and Pharmacology, presenting new peer-reviewed evidence on the application of New Approach Methodologies (NAMs) in quantitative risk assessment (QRA) of fragrance materials.

The study demonstrates that SenzaGen’s single-assay method GARD®skin Dose-Response, alongside the multiple-assay approaches, delivers PoDs that well align with established human and animal reference potency data, within the expected biological variability.

Read the full article

Establishing safe dose levels for cosmetic ingredients

We are pleased to see another leading global cosmetics company adopt GARD®skin Dose-Response to assess safe use levels of ingredients with potential skin-sensitizing properties. Powered by genomics and machine learning, the assay can be used as a standalone method to support robust, science-driven product development.

Explore 3 typical use scenarios

Upcoming events

🌎 Conference: ITCASS and ERGECD meeting | Strasbourg, France | April 15-17
🎧 Webinar: Advancing NAMs for respiratory sensitization testing-SOT Recap | Apr 22
🌎 Conference: ESTIV Congress | Maastricht, the Netherlands | June 29-July 2

New peer-reviewed publication by IDEA working group: Derivation of a Point of Departure using NAMs for application in Quantitative Risk Assessment of fragrance material

Advancing quantitative NAMs for skin sensitization risk assessment – Collaborative work within IDEA QRA-NAMs Working Group

A new article published in Regulatory Toxicology and Pharmacology presents the outcomes of collaborative work within the International Dialogue for the Evaluation of Allergens (IDEA) QRA-NAMs Working Group.

The publication demonstrates how quantitative New Approach Methodologies (NAMs) can be used to derive Points of Departure (PoDs) for skin sensitization risk assessment.

The study provides peer-reviewed evidence that SenzaGen’s single-assay method GARD®skin Dose-Response, alongside the multiple-assay approaches, delivers PoDs that well align with established human and animal reference potency data, within the expected biological variability.

We are proud that SenzaGen expert Dr Andy Forreryd contributed to the scientific discussions and to the development of the GARD®skin dose-response methodology supporting this work.

About the study

Three quantitative NAM approaches were evaluated across 110 fragrance-related chemicals, benchmarked against the extended IDEA Reference Chemical Potency List (RCPL), which integrates human and animal reference data:
  • Defined approaches combining multiple assays: Regression model and SARA-ICE.
  • GARD®skin Dose-Response: a genomic-based assay evaluated as a stand-alone method.

Scientific and regulatory impact

The work addresses a critical gap in NAM adoption: moving beyond hazard identification to quantitative, decision-relevant risk assessment.

Importantly, the study goes further than method comparison by defining NAM-specific adjustment factors, enabling translation of NAM-PoDs into NESILs for use in Quantitative Risk Assessment (QRA), even for new materials where no legacy data are available. Together, these results provide a scientifically robust and practically applicable framework for implementing quantitative, NAM-based skin sensitization risk assessment and support the continued transition toward animal-free, human-relevant safety assessment.

 

ndreas Natsch, Peter Griem, Amaia Irizar, James Bridges, Matthias Vey, Isabelle Lee, Anne Marie Api, Petra Kern, Ian Kimber,
Derivation of a Point of Departure using NAMs for application in Quantitative Risk Assessment of fragrance materials,
Regulatory Toxicology and Pharmacology,
Volume 167,2026,106052,ISSN 0273-2300,https://doi.org/10.1016/j.yrtph.2026.106052.
https://www.sciencedirect.com/science/article/pii/S0273230026000255

Keywords

Skin sensitization, In vitro testing, Point of departure, Quantitative risk assessment, SARA-ICE, Regression model, GARDskin


Abstract

Skin sensitization is a key endpoint for the safety assessment of topical consumer products. Ingredients with the potential to act as skin sensitizers differ markedly in their threshold for induction but can be used safely if their potency is characterized and exposure remains within an appropriate margin of safety. To this end, the fragrance industry co-developed Quantitative Risk Assessment (QRA) which starts with the No-Expected-Sensitization-Induction-Level (NESIL). Historically, QRA relies on a weight of evidence approach based on animal data, human confirmatory tests and read across. To allow an approach based solely on New Approach Methodologies (NAMs), the International Dialogue for the Evaluation of Allergens (IDEA) initiative, developed an extended Reference Chemical Potency List (RCPL) integrating human and animal data to derive potency values (PV). Here, we use PVs to evaluate the suitability of quantitative NAMs, including Defined Approaches (DAs), to derive a Point-of-Departure (NAM-PoD) for skin sensitization potency assessment. Evaluation of NAM-PoD derived by SARA-ICE DA, Regression DA and GARDskin dose-response assay (GSDR), indicates that the sensitization potency of fragrance chemicals can be reliably predicted using each approach. Through comparison of NAM-PoDs with in vivo human sensitization thresholds, NAM-specific adjustment factors were derived to convert NAM-PoDs into NAM-NESILs for QRA.

 

In Vitro Skin Sensitization Testing of Medical Devices

Read more

SenzaGen’s Newsletter Q4 2025

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SenzaGen Newsletter Q4, 2025

As 2025 draws to a close:
This quarter caps a year of significant progress in advancing non-animal sensitization testing and closing critical data gaps. Combing genomics and machine leaning, GARD® continues to deliver solutions for Safe Dose Levels, Medical Devices, and Challenging Chemicals—driving the shift toward reliable, human-relevant approaches.

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How do you establish safe dose levels for sensitizers during product development?
This question has been front and center at international conferences and webinars this quarter, including ICT and ASCCT, where we’ve shared insights on GARD®skin Dose-Response—a unique method that delivers quantitative sensitization potency data as a stand-alone solution, without combining results from multiple tests.

Applicability to challenging samples
A key discussion point: GARD® can address not only neat chemicals but also complex mixtures like UVCBs, natural extracts, formulations, and hydrophobic materials, making quantitative risk assessment robust for diverse applications.

Quantitative data gain momentum across industries 
Interest is growing across sectors, from cosmetics and chemicals to medical devices and now also high-tech industry, because this approach supports early screening of new ingredients and materials and enables safer, more efficient innovation.

Discover how GARD® enables the derivation of Points of Departure (PoDs) for Quantitative Risk Assessment (QRA), and helps establish safe dose levels for identified sensitizers.

Here’s what you need to know as you plan for 2026: Watch webinar replay
2129 Biocompatibility testing of medical devices

In vitro biocompatibility testing: a cost-efficient, human-relevant and ethical alternative
New data on GARD®skin for Medical Devices was a key highlight at the Biocompatibility Conference in Berlin this November, underscoring how NAMs are gaining traction within ISO 10993. Our experts shared insights on integrating in vitro approaches into efficient biocompatibility strategies.

Interested in the new skin sensitization data? Request our poster to learn more
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UK signals shift to non-animal testing
The UK’s strategy to end regulatory animal testing for skin sensitization, irritation, and eye irritation by 2026 reflects the rapid move toward validated non-animal methods. SenzaGen supports this transition with GARD® for skin sensitization, as well as GLP-compliant skin and eye irritation testing, backed by scientific expertise and personalized guidance.

UK ends animal testing for skin sensitization by 2026 – Read road map
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Expanded lab facilities now open in Lund
Last month, SenzaGen celebrated the opening of our expanded laboratory in Lund. As regulatory initiatives accelerate the shift to non-animal testing, we are ready to support this change with increased capacity, flexibility and innovative solutions. Join us in celebrating this important step enabling the transition to non-animal testing!

Discuss your testing needs with our scientific team
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SenzaGen’s Newsletter Q3 2025

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Safe dose levels for sensitizers, NESIL values for HRIPT, and PoD-based QRA
Skin sensitization potency assessment has been in the spotlight at several toxicology conferences this summer, particularly for fragrances where defining safe dose levels, establishing NESIL values, and applying Point of Departure (PoD)-based Quantitative Risk Assessment (QRA) remain key challenges.

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Webinar: In vitro skin sensitization potency assessment
Our on-demand webinar demonstrates how GARD®skin contributes to these needs with case studies on fragrances, essential oils, botanical extracts, and complex mixtures, in collaboration with Unilever, BIC, Takasago, dōTERRA, IFF, and RIFM.
WATCH THE RECORDING
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OECD TG 497 regulatory update at Eurotox
Thank you to everyone who visited us at this year’s Eurotox and joined the discussions on what GARD®skin’s inclusion in OECD TG 497 means for high performance and extended applicability within the DASS framework. We presented posters and led an interactive session demonstrating applications across complex substance categories such as UVCBs, natural extracts, hydrophobic materials, and formulations.

Connect with our specialists to discuss what this means for your regulatory testing strategy
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GARD® enters final ISO validation

– 100% reproducibility and 97% concordance
At the recent ISO TC 194/WG 8 meeting, SenzaGen presented pre-validation results for GARD®skin Medical Device. The assay achieved 100% reproducibility and 97% concordance with animal data, confirming it is robust and ready for the next step: interlaboratory ring trial validation. This milestone advances NAMs in ISO standards, supporting the shift to non-animal skin sensitization assessments.

Request the poster with full pre-validation data

Upcoming events
🌎 ICT 2025 | Beijing, China | Oct 15-18
🌎 ASCCT 2025 | Gaithersburg, USA | Oct 21-23
🌎 3rd Annual Medical Device Biocompatibility Conference | Berlin | Nov 6-7
🎧 Webinar: How GARDskin fits into OECD TG 497 | Nov 20

Joint poster with Urgo: Supporting hypoallergenicity claims for Medical Wound Dressings

Supporting industry decision-making and hypoallergenicity claims using an experimental setup combining GARD®skin Medical Device and Dose-Response protocols.

Presented at 2025 Eurotox

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Conclusion

This case study demonstrates how NAMs like GARD® can be effectively integrated into product development for assessing skin sensitization potential in medical device extracts. It enables evidence-based decision-making and supports hypoallergenic claims, without the use of animal testing.

​

Abstract

Biocompatibility testing is a crucial part of medical device safety assessments both for regulatory acceptance of finished products but also within the developmental pipelines of novel devices. Along with cytotoxicity and irritation, skin sensitization is a key toxicological endpoint that must be assessed for all devices. While testing for the two former endpoints is partly conducted in vitro, traditional animal experimentations for skin sensitization testing are still routinely conducted. Thus, validation and implementation of New Approach Methods (NAMs) remains a prioritized goal of the medical device industry.

The GARDskin method (OECD 442E) is a NAM for hazard assessment of skin sensitizers based on test chemical exposure of dendritic cell-like cells followed by a genomic readout. Several method adaptations have been proposed in order to address specific needs of various industry segments. Such adaptations include the GARDskin Dose-Response (DR) method, which facilitates quantitative assessment of sensitizing potency, and the GARDskin Medical Device (MD) method, which facilitates testing of solid materials in accordance with ISO 10993 standards.

Here we report an experimental setup combining the protocols of above-mentioned GARDskin adaptations used to evaluate the relative hypoallergenicity of two sensitive skin dressings: a candidate product and a marketed comparative product. The extraction from the solid test items was performed according to ISO 10993-12, but with an increased test item to extraction vehicle ratio of 6x. The oversaturated extracts were subsequently subjected to serial dilution facilitating dose-response testing in order to evaluate, assess and compare the test items’ relative skin sensitizing potentials.

The results concluded that both test items were classified as non-sensitizers. Due to the oversaturation extraction procedure, otherwise adhering to the ISO 10993-12 standards, the results are noteworthy. Indeed, due to the manyfold increase in material to vehicle ratio, labelling the tested skin dressings as hypoallergenic, or otherwise suitable for sensitive use, may be supported by the data. Furthermore, evaluation of the relative difference between the two test items concluded that the comparative test item induced elevated response values at the highest tested concentration, whereas the candidate test item did not. As such, it could be argued that the candidate product can be claimed as hypoallergenic similarly to the comparative product.

In summary, this experimental setup combining GARDskin MD and GARDskin DR protocols can successfully be used to support claims of hypoallergenicity of medical devices, as well as comparing candidate products with respect to their relative skin sensitizing potential. These results illustrate how such strategies can be routinely integrated in the development of novel devices giving data for critical decision-making without resorting to animal experimentation for regulatory approval.

Joint poster with BIC: Case study on skin-binding dyes

In vitro skin sensitization potency assessment using GARD®skin Dose-Response: A case study on natural extracts-based skin-binding dyes and dye precursors

Presented at 2025 Eurotox

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Conclusion

  • GARD® skin Dose-Response provides ready-to-use NESIL values, supporting the establishment of safe dose levels for skin sensitizers.
  • The assay is a non-animal alternative for skin sensitization potency testing, enabling potency ranking of candidate products and quantitative risk assessment.

​

Abstract

Naturally occurring skin dyes and dye precursors are widely used in temporary tattoo products, evolving from unrefined fruit extracts to more refined formulations in various ink applications. Evaluating their skin sensitization potential and establishing safe use levels for potential sensitizers are critical for product safety, which has traditionally relied on animal testing and/or human patch testing. While New Approach Methodologies (NAMs) have been developed to replace in vivo assays, a need remains for methods that can effectively and quantitatively characterize skin sensitizing potency.

GARD®skin (OECD TG 442E) is an in vitro assay that identifies chemical skin sensitizers based on the transcriptional profiling of a 196-gene biomarker signature in the dendritic-like SenzaCell® cell line. Predictions are made using a machine-learning algorithm, which classify test chemicals as sensitizers or non-sensitizers based on the assay’s readout, Decision Values (DVs).  GARD®skin Dose-Response (OECD TGP 4.106) extends this approach by evaluating test chemicals across a concentration range to establish a dose-response relationship between DVs and test chemical concentration. Sensitizing potency is quantified using cDV0, the lowest dose required to elicit a positive response in GARD®skin. Depending on the need, the readout can be used to predict LLNA EC3 values, No Observable Effect Levels (NOELs)/No Expected Sensitization Induction Levels (NESILs), Human Potency (HP) Categories, and UN GHS/CLP classification (1A or 1B), all with high statistical significance.

This case study demonstrates the application of GARD®skin Dose-Response to quantitatively assess the skin sensitization potency of naturally occurring dye precursor that binds covalently to skin molecules, highlighting its use in temporary tattoo inks. Seven analogue molecules with different functional groups were investigated. While six exhibited varying degrees of sensitization potency with mean cDV0 values ranging from 3.82 µM to 34.3 µM, one functional group did not induce a positive response at any of the assayed concentrations and was subsequently classified as a non-sensitizer. Predicted LLNA EC3 values ranged from 0.60% to 4.72%, corresponding to Human Potency Categories HP2 to HP4, with NESIL estimates between 258 to 2840 µg/cm².

These findings demonstrate that GARD®skin Dose-Response provides ready-to-use NESIL values, enabling potency ranking of candidate ingredients and supporting the safety assessment of novel dyes and dye precursors. The study further highlights the assay’s value as a non-animal alternative for skin sensitization potency assessment in product development.

Joint poster with dōTERRA: Case study on Essential Oils

Comparative analysis of skin sensitization thresholds for Essential Oils: Human, murine, and GARD®skin Dose-Response

Presented at 2025 Eurotox

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Conclusion

  • NESIL predictions from GARD® were consistent with other skin sensitization data, particularly when compared to reference human data (HRIPT) and constituent predictions.
  • The assay supports quantitative skin sensitization potency assessment of complex mixtures, offering a reliable non-animal alternative to traditional testing methods.

​

Abstract

Essential oils (EOs), widely used in consumer products, require robust skin sensitization hazard and potency assessment. However, dose-response thresholds for EOs remain understudied, and current classifications under CLP mixture criteria are often overly conservative. Traditional methods, such as animal testing and human patch tests, face ethical concerns, regulatory restrictions, and reliability issues. While New Approach Methodologies (NAMs) address some of these challenges, most of them are validated only for hazard identification and lack quantitative potency assessment capabilities.

GARD®skin (OECD TG 442E) is an in vitro assay that identifies chemical skin sensitizers based on the transcriptional profiling of a 196-gene biomarker signature in the dendritic-like SenzaCell® cell line. Predictions are made using a machine-learning algorithm, which classify test chemicals as sensitizers or non-sensitizers based on the assay’s readout, Decision Values (DVs). GARD®skin Dose-Response (OECD TGP 4.106) extends this approach by evaluating test chemicals across a concentration range to establish a dose-response relationship between DVs and test chemical concentration. Sensitizing potency is quantified using cDV0, the lowest dose required to elicit a positive response in GARD®skin. Depending on the need, the readout can be used to predict LLNA EC3 values, No Expected Sensitization Induction Level (NESIL), and UN GHS/CLP classification (1A or 1B), all with high statistical significance.

This study evaluates the utility of GARD®skin Dose-Response to predict NESILs for EOs, bridging the gap between hazard identification and quantitative risk assessment. Three EOs (A, B, C) were analysed using GARD®skin Dose-Response. Their skin sensitization potency threshold levels were estimated by the assay readouts (cDV0) and NESIL predictions. Results were compared to existing murine (LLNA EC3) and human (HRIPT/HMT) data through weight-of-evidence analysis.

For test item A, the predicted NESILs spanned were 5700 (GARD®), 6900 (constituent prediction), 1800 (LLNA), 2000 (HRIPT), and 3500 µg/cm² (HMT). Test item B showed NESILs of 24000 (GARD®), 29000 (constituent prediction), 6700 (LLNA), 44000 (HRIPT), and 11000 µg/cm² (HMT). Test item C was classified as a non-sensitizer by GARD®skin Dose-Response, with constituent prediction, LLNA, HRIPT, and HMT NESILs at 20000, 3900, 20000, and 690 µg/cm², respectively.

NESIL predictions from GARD®skin Dose-Response aligned with other skin sensitization test results, supporting its utility in quantitative sensitization potency assessment of complex natural extracts like EOs. While confirmatory human studies (e.g., CNIH protocols) are recommended, this assay reduces reliance on animal and human testing and advances the use of NAMs in safety assessment.