Integrated hazard identification of chemical sensitizers using in vitro and in silico readouts – A comparative evaluation of predictive performance

By Lhasa

Donna Macmillan, Henrik Johansson, Olivia Larne, Malin Lindstedt
1. Granary Wharf House, 2 Canal Wharf, Leeds, LS11 5PS
2. SenzaGen, Lund, Sweden
3. Lund University, Lund, Sweden

 

Introduction

There has been a significant drive to reduce, refine and replace animal models for the prediction of skin sensitization. This is in part due to the implementation of EU regulation 1223/20091 which prohibits the sale and marketing of any cosmetics and cosmetic ingredients which have been tested on animals, alongside REACH2 and CLP3 regulations which state that non-animal methods must be exhausted prior to considering the use of animal tests. The use and availability of non-animal methods is ever-increasing and 3 assays have been validated by the OECD thus far; the in chemico DPRA, the in vitro KeratinoSens™ and the in vitro h-CLAT. A number of other assays are undergoing OECD validation, including the GARDskin assay (Genomic Allergen Rapid Detection), a dendritic cell-based assay which identifies skin sensitizers from 200 genomic biomarkers4. However, it is generally accepted that no single non-animal method can be used as a standalone approach to replace animal models such as the murine local lymph node assay (LLNA). The focus has instead turned to combining multiple in chemico/in vitro/in silico assays and/or molecular descriptors to derive a more accurate assessment of hazard or risk, known as integrated testing strategies (ITS)5. The GARDskin assay has demonstrated high predictivity and has been reported as ready to use in an ITS6, therefore, it was decided to investigate the effect on performance when GARD was used in combination with Derek Nexus – and to compare these results against Derek with the DPRA, KeratinoSens™ and h-CLAT.

 

Conclusion

Using Derek skin sensitization predictions in combination with in chemico/in vitro assay results has a beneficial effect when predicting the LLNA outcome. GARDskin in particular performs extremely well when used with Derek in a conservative call approach. Human sensitization is more challenging to predict and GARDskin performs less well for this compared to predicting the LLNA – attributed to the small number of chemicals with both GARDskin and human data (n = 57), in addition to the positive bias in the GARD dataset (70%). However, the addition of Derek predictions clearly improve assay performance. Future work will focus on repeating this analysis on a larger, more balanced dataset.

Poster at Lhasa website
https://www.lhasalimited.org/publications/integrated-hazard-identification-of-chemical-sensitizers-using-in-vitro-and-in-silico-readouts-a-comparative-evaluation-of-predictive-performance/4428

 

New colleague at SenzaGen

Welcome to SenzaGen Anna Chérouvrier Hansson!

Anna has started her position as Chief Commercial Officer with us here at SenzaGen this week. Anna comes from Camurus, a pharmaceutical company developing and commercializing innovative and long-acting medicines for the treatment of severe and chronic conditions. At Camurus, Anna was Director of Marketing and responsible for the Medical Device Business Unit. She has previously worked as Head of Business Development Life Science at Invest in Skåne, Partner at Zitha Consulting and in a number of senior positions in European pharmaceutical and chemical companies. Anna was born in France, studied and worked in Germany and Luxembourg before moving to Sweden in 2000 to study a Master in Business Administration and Business Law and decided to stay. Anna strengthens SenzaGen’s management for the commercialization of the GARD tests and prior to the company’s planned listing on Nasdaq First North.

We are very happy to have you in our team, Anna!

senzagen skin derma

Möt oss i Almedalen – Forskarna bakom GARDtestet och SenzaGens tekniker på plats.

Möt Andy Forreryd från Lunds Universitet och Angelica Johansson från SenzaGen i Forska Utan Djurförsöks event 6 och 7 Juli. Under två seminarier berättar Andy om forskningen bakom GARD. Det bjuds möjligheter till frågor och att testa på praktiskt labbarbete med testet.
Med forskningspengar från bland andra Forska Utan Djurförsök har universitetet utvecklat ett unikt allergitestet som med högre precision än befintliga tester kan avgöra om en kemikalie kan framkalla hudallergi. Testet utförs i provrör och ersätter befintliga djurtester vid säkerhetstestning av kemikalier. GARDtestet ägs, säljs och marknadsförs nu av SenzaGen AB för global kommersialisering med målet att bli ny branschstandard på den internationella marknaden för säkerhetstestning av kemikalier. Angelica Johansson finns på plats att berätta om GARDs resa från labb till global marknad. Tryck här för att läsa mer.

senzagen skin derma

Meet us in Almedalen – The researchers behind the GARDtest and SenzaGen’s lab technicians on site.

Meet Andy Forreryd from Lund University and Angelica Johansson from SenzaGen in the organisation of Research Without Animal Experiments, 6th and 7th of July. During two seminars, Andy will tell us about the research behind GARD. There will be opportunities for questions and hands on practical lab work so that you can experience and see how the test works.

With research money from different organisations, including Research Without Animal Experiments, the university has developed a unique allergy test that with higher precision than existing tests can determine if a chemical can induce skin allergy. The test is carried out in test tubes and replaces the need for animal testing when safety testing chemicals.

The GARDtestet is now owned, sold and marketed by SenzaGen AB for global commercialization with the aim of becoming a new industry standard on the international chemical safety testing market. Angelica Johansson is on site to talk about GARD’s journey from laboratory to global market. Link in Swedish.

Performance of the GARD assay in a blind Cosmetics Europe study

Johansson H, Gradin R, Forreryd A, Agemark M, Zeller K, Malmborg-Hager A1, Johansson A, Larne O, Van Vliet E3, Borrebaeck C, Lindstedt M,
SenzaGen AB, Lund, Sweden, Department of Immunotechnology, Lund University, Lund, Sweden, Cosmetics Europe –The Personal Care Association, Brussels, Belgium

Introduction

Chemical hypersensitivity is an immunological response to foreign substances. Primarily, these give rise to the clinical symptoms known as allergic contact dermatitis. To mitigate risks associated with consumer products, chemicals are screened for sensitizing effects. Historically, such predictive screenings have been performed using animal models, but industrial and regulatory authorities now demand animal-free methods for the assessment of sensitization. This is a global development spreading across industries and markets. To meet this demand, the Genomic Allergen Rapid Detection (GARD) assay has been developed. Here, we present novel data reconfirming the performance and accuracy of GARD.

Resume

The performance of GARD is highly accurate
83% (72 chemicals)
86% (127 chemicals)
83% (72 chemicals)
Correlated GARD predictions and potency classifications

Poster

senzagen gard session

SenzaGen is presenting at hosted sessions at Society of Toxicology 56th Annual Meeting in Baltimore March 12-16, 2017

Lund University Scientist Andy Forreryd and SenzaGen CEO Anki Malmborg Hager will give a presentatios about the GARD assay at exhibitor hosted sessions at the Society of Toxicology 56th Annual Meeting in Baltimore, on the 13th and 14th of March.

The meeting promises more than 150 scientific sessions, approximately 350 ToxExpo exhibitors offering you the latest information on services and technology, thousands of abstract presentations, continuing education courses, awards presentations, receptions, career guidance and support, and more.

Presentations details

– Replacement of Animal Testing for CLP/GHS Classification of Skin Sensitizers is now possible using a Modified Genomic GARDskin [OECD TGP 4.106] Assay
SenzaGen presents the latest development towards reliable potency classification of chemicals according to CLP 1A and 1B, taking both LLNA and Human potency data in consideration. The assay is based on GARDskin and utilizes a refined gene expression signature developed specifically for potency categorization with high predictability.

Date: 3/13 Time: 13:30 -14:30  Room: 338

– Advantages with Genome Testing Opening up the Landscape for New Application Possibilities for Sensitization Testing using SenzaGen’s Genomic GARD Assay
SenzaGen’s GARD assay is based on expression analysis of predictive genomic biomarker signatures. Prediction calls of test substances are generated by computational methods based on machine learning. SenzaGen presents their experience in skin and respiratory sensitization testing, working with challenging compounds and mixtures, active substances, potency classification and NOEL interpretation.

Date: 3/14 Time: 13:30-14:30  Room: 338

These session are Exhibitor-Hosted Session. Although not an official part of the SOT Annual Meeting scientific program, its presentation is permitted by the Society.

Attendees are welcomed from researcher community, industry, manufacturers, regulatory agencies, consultants, CROs and every one interested in safety testing of chemical compounds.

podd with anki malmborg hager

Podcast – interview with CEO, Anki Malmborg Hager and professor Carl Borrebaeck

The GARD™ assay for potency assessment of skin sensitizing chemicals

Kathrin S. Zeller, Andy Forreryd, Tim Lindberg, Ann-Sofie Albrekt, Aakash Chawade, Malin Lindstedt
Dept. of Immunotechnology, Lund University, Lund, Sweden; Swedish University of Agricultural Sciences, Alnarp, Sweden

Summary
The GARD assay is a cell-based transcriptional biomarker assay for the prediction of chemical  ensitizers1 targeting key event 3, dendritic cell activation, of the skin sensitization AOP. Here, we present a modified assay based on Random Forest modelling, which is capable of predicting CLP
potency classes (1A – strong sensitizers, 1B – weak sensitizers, no category – non-sensitizers) as described by the European CLP regulation with an accuracy of 75 % (no cat), 75 % (1B) and 88 % (1A) based on a test set consisting of 18 chemicals previously unseen to the model.
We further can link the activation of distinct pathways to the chemical protein reactivity, showing that our transcriptomic approach can reveal information contributing to the understanding of underlying mechanisms in sensitization.

Results and Discussion
We here present a potency prediction approach based on a Random Forest model and 18 transcripts. 18 chemicals previously unseen to the model were classified as shown in Tables 1, 4 and Fig. 1. Interestingly, diethyl maleate, misclassified as 1A instead of 1B, is a human potency class 2 according to4, and iodopropynyl butylcarbamate, wrongly predicted as 1B instead of 1A, is classified as human potency class 44. Thus, the model seems to show more agreement with human data than CLP classifications (mainly derived from animal data) based on this limited dataset. Also Fig. 1C supports the hypothesis, that both data and model contain information allowing the prediction of human potency.
Furthermore, Key Pathway Advisor analysis reveals that these data can be used to investigate the cellular response in more detail (Table 3). In conclusion, we show that the modified GARD assay is capable of providing potency information, which is imperative for quantitative risk assessment of chemical sensitizers.

The GARD assay for potency assessment of skin sensitizing chemicals_ESTIV 2016_Zeller_p

GARD™ – The story

Olivia Larne, Andy Forreryd, Ann Sofie Albrekt, Carl Arne Krister Borrebaeck, Henrik Johansson, Malin Lindstedt
SenzaGen, Sweden, Lund, Department of Immunotechnology, Lund University, Sweden, Lund

 

Background

To prevent the general population for unnecessary exposure to sensitizing substances, the substances have to be safety tested. Regulatory authorities and economic interests request animal free methodology. Genomic Allergen Rapid Detection, GARD, is an in vitro test developed for the prediction of sensitizing chemicals. It is based on differential expression of disease-associated genomic biomarkers in a human myeloid dendritic cell line.
Here, we describe the development of the GARD platform and its downstream innovations.

Poster:
GARD – The Story_ESTIV 2016