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Confidence in New Approach Methodologies for Risk Assessment

February 13, 2024

Welcome to the new age of chemical testing. Thanks to technology, the longstanding standard of using animals for research to determine if a chemical is harmful now has company, collectively known as New Approach Methodologies (NAMs). Blood or tissue samples, computational modeling, chemical prioritization, and other methods for assessing a chemical’s risk have the potential to replace, reduce, refine (3Rs), or complement the use of animals.

But NAMs are controversial. Supporters note that the techniques and approaches require fewer resources and can work faster than traditional animal studies to answer critical risk assessment questions. NAMs offer the potential of analyzing effects on diverse human populations, which animal studies can’t do. NAMS also avoid harm to animals. And while animal studies may be the gold standard, they aren’t perfect. Rats, after all, aren’t humans and can react differently to chemical exposure.

But there are valid concerns about the readiness of certain NAMs to be the sole basis for informing rulemaking. NAMs offer different data from animal studies, and NAMs’ ability to accurately predict safe dosage levels is a subject of debate.

Abt Global has been working to advance the science around chemical risk assessment and support confidence building for the development, evaluation, implementation, and acceptance of NAMs. Most recently, Abt attended a virtual meeting of the Scientific Advisory Committee on Alternative Toxicological Methods, where the role of NAMs in improving environmental health protection was a critical discussion item. In addition, at the annual meeting of the American Society for Cellular and Computational Toxicology, Abt health-risk expert Meghan Lynch presented a research poster on tools for estimating biological levels of harmful and ubiquitous PFAS, called “forever chemicals” because they are hard to break down chemically. The tools enable people to estimate the amount of PFAS in their bodies based on physiological characteristics.

Concern about NAMs was evident at these meetings. The level of confidence in NAMs affects their implementation and acceptance in the scientific community, which includes government, industry, academia, and non-profit organizations. Confidence also affects the use of chemical risk assessment data stemming from NAMs research by regulatory agencies charged with protecting and preserving public health, human health, and the environment.

Questions about NAMs center around whether to apply what looks good in a research lab setting to the regulatory context, where lives potentially are at stake. Are NAMs as credible as or better than currently accepted evidence? Earlier this year, the National Academy of Sciences published a report suggesting the potential of NAMs to inform timely decision-making when no animal study or epidemiological data are available. The report also mentioned the potential use of NAMs to provide data that could help protect susceptible and vulnerable populations.

NAMs data are currently considered for review in new chemical and drug applications. Some agencies have collaborated to develop computer simulations to determine if new chemicals can cause cancer, a critical analysis before allowing their sale. U.S. regulatory agencies have not yet fully accepted non-animal studies as the main source of evidence for setting safe levels of exposure.

But a key milestone in NAMs’ non-animal testing acceptance was the Organization for Economic Cooperation and Development’s adoption of ways to predict skin sensitization potential without harming animals. A review of the literature could provide evidence of other contexts in which NAMs could be consistent with accepted human health risk assessment frameworks.

Abt has extensive experience with literature reviews, from meta-analyses to quick-turnaround summaries, reference lists, and annotated bibliographies. Our work includes screening studies, extracting data, characterizing chemical risk, and developing evidence maps that help to visualize and combine different types of evidence and ensure transparency. We apply reproducible methods to develop, evaluate, and validate computational and alternative testing methods.

One is called physiologically based pharmacokinetic modeling (PBPK). It uses mathematical modeling to predict such things as the absorption, metabolism, and excretion of chemical substances in humans and other animal species. Another is bioassay design and implementation to determine the potency of a substance.

We have extensive experience supporting clients when they develop and improve critical decision-making frameworks that impact potential regulations and policies that protect against toxic effects of contaminants. This regulatory development support includes collecting and analyzing key information, drafting white papers and issue papers on baseline and policy options, and identifying key stakeholders. It’s only part of our full suite of capabilities to support our clients in meeting statutory requirements to serve and protect the public.

Confidence building around NAMs will have broad impacts on science and policy. Achieving acceptance is a multifaceted challenge, which includes communication, scientific validation, data gathering and analysis, rulemaking, and risk management. Abt is working on all of these fronts to ensure that NAMs can be a valid option for protecting human health and the environment.

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