Last month, the Organisation for Economic Co-operation and Development (OECD) ran a webinar outlining how to apply its latest guideline on in silico tools to assess skin sensitisation, the Implementation of the Defined Approaches on Skin Sensitisation (OECD GL 497). The webinar featured presentations from a range of experts at various European and US agencies, including the European Chemicals Agency (ECHA), the EU Reference Laboratory for alternatives to animal testing (EURL ECVAM) – part of the European Commission’s Joint Research Centre (JRC) – and the US Food & Drug Administration (FDA).
‘Reduce reliance’ on animal testing
Opening the webinar, Anne Gourmelon, principal administrator of test guidelines at the OECD, said there was a clear need for this latest guideline, because non-animal methods could not be used in isolation or as drop-in replacements to assess chemicals for skin sensitisation.
“The overall purpose of the guideline is to provide information that is equivalent to that which is provided by the standard animal test. Of course, this is to reduce reliance on animal testing as requested by the different regulatory sectors. It is embraced by the OECD,” Gourmelon told attendees.
And the work behind the guideline, she said, had been ongoing on for decades, with input from a wider range of experts, groups, companies and associations, notably the European trade association Cosmetics Europe.
Nicole Kleinstreuer, acting director at the US National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM), said the guideline was a “landmark moment” for the OECD.
“It’s the first defined approach guideline that is intended as a full replacement for animal test methods. Hopefully it’s not the last,” Kleinstreuer said.
She said that because the combination of in silico methods outlined in the OECD guideline had been proven to provide “robust” predictions for hazard and potency of chemicals, and were “equivalent or better” in predicting human reference end points compared to animal data, there was plenty to be learned when developing future defined approach guidelines, she said.
‘Reliable methods’ to assess skin sensitisation
Laura Rossi, scientific officer at the European Chemicals Agency ECHA, said information on skin sensitisation was hugely important given it was one of the most common occupational and environmental health issues worldwide.
“It’s estimated that about 25-30% of industrial chemicals are skin sensitisers. This is confirmed with data we have in our database. Therefore, it is really important to have reliable methods to predict the skin sensitisation potential of chemicals in order to protect workers and consumers,” Rossi said.
In Europe, she said the latest OECD guideline could be used to provide data on skin sensitisation – a legal obligation when submitting a REACH dossier – but companies had to be sure data was conclusive, with details on potency if a substance was considered a skin sensitiser.
If the defined approaches resulted in “inconsistent data” or an “inconclusive result”, she said REACH required other studies to be performed or weight-of-evidence assessment to be improved; with in vivo studies a “last resort”.
ECHA recently published its own guidance on how to apply the OECD defined approaches under REACH – a resource Rossi said would be important for industry moving forward as companies familiarised themselves with the non-animal alternatives in the guideline.
“Get to know the OECD guideline and the guidance we have prepared,” she told attendees during the webinar.