Applicability domain of the GARD™skin Medical Device test for in vitro skin sensitization testing of medical devices

Poster presented at SOT 2021

Joshua Schmidt, Ron Brown and Rose-Marie Jenvert
SenzaGen Inc., Raleigh, NC, USA, Risk Science Consortium LLC, Arnold, MD, USA, SenzaGen AB, Lund, Sweden.

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Conclusion

  • The chemical space of compounds tested in GARD closely approximates the chemical space of compounds known to be released from medical device materials.
  • GARDskin is able to predict the skin sensitization potential of compounds released from medical device materials with a high degree of sensitivity and specificity, including: metals, lipophilic compounds and pre/pro haptens.

Abstract

Medical device toxicology is undergoing an exciting evolution; transitioning from a process that largely relied on the results of animal testing to evaluate the biological safety of devices in patients to one which is increasingly focused on the use of in vitro methods for the safety assessment of device materials.

Recently, in vitro methods to assess endpoints such as skin irritation and pyrogenicity have been validated and proposed for medical device testing, but a method to assess the potential for device-related skin sensitization to occur has not been sufficiently qualified. A number of in vitro skin sensitization test methods have been shown to have acceptable predictive ability for known skin sensitizers with structures that span a broad range of chemical classes, but the predictive ability of these methods has not been specifically evaluated using compounds typically found in materials used to manufacture medical devices. As a result, the need exists to qualify in vitro methods to assess the skin sensitization of compounds that may be released from medical devices, taking into account the applicability domain of known or potential skin sensitizers, including metals.

To address this challenge, the predictive ability of the GARD assay has been evaluated using a dataset of compounds known to be released from device materials.  Against these data, the assay correctly predicted 19 out of 21 lipophilic and pre-/pro-hapten compounds (90.5% accuracy), with one false positive (95.2% sensitivity) and one false negative (95.2% specificity) being predicted, thus increasing the confidence in use of this in vitro assay to assess the skin sensitization potential of medical devices.  Furthermore, we have also demonstrated that the GARD assay correctly predicts the skin sensitization response of nickel and cobalt salts (sensitizers) and a zinc salt (non-sensitizer). Overall, our data support the use of the GARDskin Medical Device assay as an in vitro alternative for the in vivo methods (e.g., GPMT, LLNA) that are typically used to assess skin sensitization as part of the biological safety assessment of medical devices.

Webinar: Safer Medical Devices

Safer Medical Devices – in vitro skin sensitization testing with human relevance and high accuracy
By Rose-Marie Jenvert, PhD, and Joshua Schmidt, PhD, SenzaGen

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In vitro skin sensitization testing of Medical Devices using GARD®

Rose-Marie Jenvert, Angelica Johansson, Olivia Larne, Emelie Danefur, Emil Altonen, Anders Jerre, Robin Gradin, Gunilla Grundström.
SenzaGen, Lund, Sweden.

Introduction
All medical devices need to be evaluated for the end point skin sensitization according to the Biological Evaluation of Medical Devices (ISO 10993-1:2018), today commonly involving in vivo assays. Here, we show that the in vitro assay GARDskin Medical Devices can classify leachables as either skin sensitizers or non-sensitizers in polar and non-polar extraction of Medical Devices.

Conclusion
GARDskin Medical Device

  • is an in vitro alternative for assessment of skin sensitization of Medical Devices
  • is compatible with the extraction vehicles salin, olive oil and sesame oil.

Link to poster

Poster presented at Eurotox, Helsinki, Sep 9, 2019.

Extended applicability domain with new solvent selection for the GARD platform

Jenvert RM, Larne O, Torstensdotter MattssonU. I., Johansson H, SenzaGen, Lund, Sweden

Introduction
The Genomic Allergen Rapid Detection (GARD) assay is a state of the art in vitro assay developed for the assessment of skin sensitizers. It is based on gene expression analysis of SenzaCells, a human myeloid cell line, after stimulation by the test item.
During the development of the GARD platform, two solvents were used; DMSO (0.1%) and Water. To increase the applicability domain of GARD® and the solubility of certain test items, for e.g. Medical Device extracts and UVCBs, we here show a broader range of solvents compatible with GARD.

Conclusions
Here, we show that the GARD® platform is compatible with the following solvents:
• Acetone
• Ethanol
• Glycerol
• Super refined olive oil

• DMF
• DMSO
• Water
• Isopropanol

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