Navigating the Evolution of NAMs: A 31-Year Perspective from a Practical Realist
Nigel Greene, Ph.D., Senior Consultant at ToxStrategies, a BlueRidge Life Sciences company, has spent more than three decades advancing New Approach Methodologies (NAMs), bringing a clear-eyed, experience-driven perspective to one of the most complex areas in modern toxicology. His entry into the field began in 1994, combining his background in computer science and chemistry. His first role involved developing software to predict toxicological outcomes from chemical structures—an early example of how computational tools could support decision-making in chemical safety.
That early work set the tone for a career centered on scientific utility. Over 14 years at Pfizer, Nigel applied in vitro and computational models to drug discovery, eventually joining a group focused on compound safety prediction. The goal: help discovery teams design safer drugs earlier in the pipeline. During this time, he also contributed to the EPA’s ToxCast initiative, providing failed drug candidates to improve how regulatory assays were validated against real-world outcomes.
At AstraZeneca, he took on broader leadership roles, managing computational groups, supporting off-target pharmacology efforts, and contributing to assay design and strategy.
Realism, Not Hype
Nigel describes himself as a “practical realist.” He doesn’t view NAMs as silver bullets—but he believes they’re essential. His motivation is rooted in two outcomes: reducing animal use in research and increasing the likelihood of safe, effective drugs reaching patients. “I’m a huge animal lover,” he says, and the opportunity to reduce reliance on animal testing is one of the most meaningful drivers of his work.
But his support for NAMs isn’t just ethical—it’s technical. Species differences limit the predictive power of traditional models. Nigel has long advocated for more human-relevant assays that align more closely with clinical biology. “Toxicology is going to have to go this way,” he says, pointing to the growing disconnect between legacy models and modern science.
Moving from Innovation to Impact
Nigel is particularly proud of work that improved early-stage decision-making in drug development. At AstraZeneca, he notes, no IND-enabling studies failed during his time—an outcome he attributes in part to NAMs being used for pre-screening. By filtering out high-risk compounds earlier, the team avoided wasting resources and prevented unnecessary animal testing downstream.
Still, he cautions against overselling. “Nothing is 100% predictive,” he says. Accuracy claims should be scrutinized, and models must be applied with an understanding of their scope and limitations. For Nigel, success comes not from novelty, but from proper application—choosing the right tool for the right question.
Changing Minds, Changing Systems
Much of Nigel’s work has involved navigating the cultural resistance that often slows adoption. While senior leadership in pharma often supports innovative approaches, he notes that project teams—those closest to decision-making—can be hesitant. Chemists may distrust toxicologists. Toxicologists may question modelers. Bridging these divides requires not just technical knowledge, but the ability to communicate and collaborate across disciplines.
Even across regulatory bodies, he sees differing levels of engagement. The EPA, which must demonstrate a product is unsafe, tends to be more proactive with NAMs. The FDA, requiring proof of safety before approval, often takes a more conservative stance.
Science That Moves Forward
Nigel’s career illustrates what it means to advance science with both purpose and pragmatism. For organizations trying to modernize their approach to toxicology, his experience offers a clear message: NAMs work best when they're matched to the right question, integrated with other data, and applied with eyes wide open.
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