Read-Across Uncertainties in Risk Assessments: NAM to the Rescue!

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By Margaret Whittaker posted 03-22-2018 15:32

  

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For those of us in the risk assessment arena, deriving health reference values with a classic animal-based approach is part skill and part habit, honed by years of scouring in vivo studies to identify critical health effect endpoints, executing dosimetric conversions to deduce human equivalent doses, and, more recently, grouping chemicals based on structural or mechanistic similarities to support read-across. The presenters during the 2018 Annual Meeting and ToxExpo Workshop Session “Reducing the Uncertainty of Read-Across Predictions by New Approach Methodologies: Application in Regulatory Human Risk Assessments” gave us good reason to abandon old habits and embrace new approach methodologies (NAM). 

The acronym “NAM” is pronounced alternatively like dram (as in a wee dram of spirits) or nom (as in a mystery word my son used to describe food groups when he was younger). NAM comprises in vitroex vivo, or ’omic technologies, as well as in silico and toxicokinetic modeling approaches.

Work is underway in the United States and EU to develop NAM-based approaches to facilitate animal-free hazard and risk assessment, as evidenced by the EU-ToxRisk Programme’s 30 million euro investment in NAM approaches. Although the European Chemicals Agency (ECHA) began floating the concept of NAM in a 2016 NAM workshop, its application to fulfill ECHA’s ambition of making more informed regulatory decisions with reduced animal testing is still uncommon. In the United States, NAM holds great promise in fulfilling the requirements of the Lautenberg Chemical Safety for the 21st Century Act, and the National Academies of Sciences report Using 21st Century Science to Improve Risk-Related Evaluations makes a number of good technical and research recommendations to support the incorporation of NAM into each part of the risk assessment paradigm. 

In Texas, the saying goes “Big Hat, No Cattle” to symbolize all talk and no action. NAM’s multi-attribute brim is as wide as that of a 10-gallon hat, but unlike the Texas adage, NAM is being primed to facilitate actionable and practicable improvements in the risk assessment process. 

This blog was prepared by an SOT Reporter. SOT Reporters are SOT members who volunteer to write about sessions and events they attend during the SOT Annual Meeting and ToxExpo. If you are interested in participating in the SOT Reporter program in the future, please email SOT Communications Director Michelle Werts.

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