In this interview CEO Axel Sjöblad comments the 2020 year-end report, ongoing projects, and the way forward.
SenzaGen’s sales during the full year 2020 tripled compared to 2019. Listen to CEO Axel Sjöblad commenting the 2020 performance in today’s conference call.
Thanks to all who attended our webinar ‘Why choose GARD for skin sensitization testing?’ last week. If you were not able to attend live, and wish to watch it, you can now access the webinar’s recording!
We wish you a truly happy holiday season, and we look forward to seeing you again in the new year.
SenzaGen received GLP approval
We can now offer GLP-compliant test services using the GARD™platform.
This newly released assay provides quantitative potency information related to skin sensitization.
Photosensitization research project with RIFM
A collaboration with RIFM (Research Institute of Fragrance Materials) has provided us an opportunity for further development of GARDskin to assess fragrances for potential skin sensitization when exposed to sunlight.
Webinars – GARD™ technology insights and user cases
We had a record number of attendees at our webinars this year covering essential topics ranging from genomics and machine learning to difficult-to-test samples and quantitative potency assessment. Watch any of them to learn ways that GARD can support your testing needs.
Our CEO Axel Sjöblad gave an update on our commercial progress at Redeye Life Science Day last week.
Watch the replay here:
Poster presented at ACT 2020
J. Schmidt, A. Forreryd, H. Johansson, J. Li, A. Johansson
SenzaGen, Inc., Raleigh, NC, USA, SenzaGen AB, Lund, Sweden
- GARDskin demonstrated an overall high applicability for the evaluated challenging substances with 80% predictive accuracy compared to existing human data.
- GARDskin demonstrated excellent applicability for pre/pro-haptens and low water solubility substances, correctly classifying all such compounds in the herein investigated dataset.
- GARDskin also showed high applicability for assessment of surfactants with 89% predictive accuracy compared to existing human data, correctly classifying 8 out of 9 internally tested surfactants, including well known challenging ones such as Sodium Dodecyl Sulphate (SDS) and Benzalkonium chloride.
Current legislations and trends in predictive toxicology advocate a transition from in vivo methods for hazard and risk assessments to non-animal alternatives. However, certain groups of chemicals, including substances with severe membrane-damaging properties, pre- and pro-haptens, and those with high log P ratios, have been shown to be challenging to assess using cell-based assays in the context of skin sensitization testing. The aim of this study was to evaluate the applicability of GARDskin for such challenging substances, using an overlapping subset of chemicals previously tested in an integrated tested strategy (ITS) based on validated, aqueous in vitro assays, as well as in a series of Reconstructed Human Epidermis (RHE)-based assays.
The GARDskin assay (Genomic Allergen Rapid Detection) is a robust in vitro assay for identification of potential chemical skin sensitizers with over 90% prediction accuracy and broad applicability. The assay is included in the OECD Test Guideline Program (OECD TGP 4.106) and has gone through a formal validation study. The assay evaluates the gene expression of endpoint-specific genomic biomarkers in a human dendritic-like cell line following exposure to the test substance. Exposure-induced gene expression patterns are analysed using pattern recognition and machine-learning technology, providing classifications of each test item as a skin sensitizer or a non-sensitizer.
The applicability of GARDskin for a total of twelve challenging substances, including pre- and pro-haptens, low water-soluble substances, two surfactants and three additional substances known to have conflictive results when comparing in vitro and in vivo data were evaluated in this study. All twelve substances were selected from the Mehling et al. 2019 publication which reported results from three OECD validated in vitro methods, the “2 out of 3” Integrated Testing Strategy, three RHE-based models and the murine local lymph node assay (LLNA). Human potency classification was available for ten out of the twelve substances.
The GARDskin prediction results were reported from previously published studies, or from in house validation studies. Predictive accuracies were calculated by comparing skin sensitization classifications from different test methods to the available human data of each substance respectively. (N=10). To further explore and substantiate the GARDskin applicability for surfactants, additional GARDskin data for a total of nine surfactants are presented in order to complement the Mehling dataset with respect to the availability of human data.
The GARDskin assay demonstrated overall high applicability for the evaluated challenging substances, with 80% predictive accuracy compared to existing human data. GARDskin correctly classified all pre-and pro-haptens and low water-soluble substances in the data set. Furthermore, high applicability of GARDskin for severe membrane disruptive substances such as surfactants was demonstrated, with 89% predictive accuracy compared to existing human data.
Poster presented at ACT 2020
J. Schmidt, A. Forreryd, R. Gradin, H. Johansson.
SenzaGen Inc., Raleigh, NC., SenzaGen AB, Lund, Sweden.
- As an adaptation from the GARDskin assay, GARDskin Dose-Response is suitable for quantitative skin sensitizing potency assessment of chemicals.
- The experimental readout, referred to as cDV0, corresponds to the lowest dose required to elicit a positive response in GARDskin. As such, experimental protocols are analogous to the LLNA, in which the cDV0 corresponds to the EC3-value.
- The cDV0 may be used to directly monitor sensitizing potency, or further used to extrapolate LLNA EC3-values, estimation of Human Potency categories, or CLP 1A/1B classifications.
Several non-animal methods for identifying skin sensitizers have been developed with acceptable prediction performance. However, advancement of alternative methods for skin sensitizing potency assessment is still missing although a highly sought-after endpoint. The GARDskin assay is a genomics-based in vitro assay for hazard assessment of skin sensitizers, currently progressing towards regulatory acceptance. Here, we introduce GARDskin Dose-Response (DR), in which test chemicals are evaluated by the GARDskin assay in an extended range of concentrations, in order to investigate the dose-response relationship between GARDskin classifications and test chemical concentration.
For this work, 29 chemicals of various sensitizing potencies were used to evaluate the efficacy of applying the assay in this manner. Each chemical was analyzed at several concentrations using a slightly modified GARDskin protocol. At each concentration, a decision-value was produced and a classification prediction (sensitizing or non-sensitizing) was made by the GARDskin algorithm. Afterwards, the lowest concentration where a test item would provide a positive GARDskin prediction was found using linear interpolation. This concentration (cDV0) was then hypothesized to reflect the test items skin sensitizing potency. Furthermore, when comparing cDV0 to LLNA EC3 values, a statistically significant correlation was realized between the values (correlation coefficient =0.74, p-value=4.1*10-4).
These results suggest that modifying the GARDskin protocol to accommodate dose-response measurements can provide sensitizing potency information analogous to the gold-standard in vivo methods. This presentation will further explain the testing process, expand on results, and demonstrate how this method can be used for decision-making throughout all stages of product development, without having to use animal experimentation.
Here is an interview with Principal Scientist Gretchen Ritacco, MS, explaining why RIFM has focused some of its research on the potential for light to activate fragrance materials resulting in reactions in the body’s largest organ, the skin.
Since June 2020, SenzaGen and the Research Institute for Fragrance Materials (RIFM) are collaborating to investigate in vitro methods and develop next-generation test for determining whether a fragrance material may cause photosensitization.
Read the RIFM interview here.
Robin Gradin, Angelica Johansson, Andy Forreryd, Emil Aaltonen, Anders Jerre, Olivia Larne, Ulrika Mattson, Henrik Johansson
Proactive identification and characterization of hazards attributable to chemicals are central aspects of risk assessments. Current legislations and trends in predictive toxicology advocate a transition from in vivo methods to non-animal alternatives. For skin sensitization assessment, several OECD validated alternatives exist for hazard identification, but non-animal methods capable of accurately characterizing the risks associated with sensitizing potency are still lacking.
The GARDTM platform utilizes exposure-induced gene expression profiles of a dendritic -like cell line in combination with machine learning to provide hazard classifications for different immunotoxicity endpoints. Recently, a novel genomic biomarker signature displaying promising potency-associated discrimination between weak and strong skin sensitizers was proposed. Here, we present the adaptation of the defined biomarker signature on a gene expression analysis platform suited for routine acquisition, confirm the validity of the proposed biomarkers, and define the GARDTMpotency assay for prediction of skin sensitizer potency. The performance of GARDTMpotency was validated in a blinded ring-trial, in accordance with OECD-guidance documents. The cumulative accuracy was estimated to 88.0% across three laboratories and nine independent experiments. The within-laboratory reproducibility measures ranged between 62.5% and 88.9%, and the between-laboratory reproducibility was estimated to 61.1%. Currently, no direct or systematic cause for the observed inconsistencies between the laboratories have been identified. Further investigations into the sources of introduced variability will potentially allow for increased reproducibility.
In conclusion, the in vitro GARDTMpotency assay constitute a step forward for development of non-animal alternatives for hazard characterization of skin sensitizers.
Key words: GARD, GARDpotency, in vitro, sensitization, potency, chemical sensitizers
Article on line with open access