An FDA/CDER perspective on nonclinical testing strategies: Classical toxicology approaches and new approach methodologies (NAMs)

Nonclinical testing of human pharmaceuticals is conducted to assess the safety of compounds to be studied in human clinical trials and for marketing of new drugs. Although there is no exact number and type of nonclinical studies required for safety assessments, as there is inherent flexibility for each new compound, the traditional approach is outlined in various FDA and ICH guidance documents and involves a combination of in vitro assays and whole animal testing methods. Recent advances in science have led to the emergence of numerous new approach methodologies (NAMs) for nonclinical testing that are currently being used in various aspects of drug development. Traditional nonclinical testing methods can predict clinical outcomes, although improvements in these methods that can increase predictivity of clinical outcomes are encouraged and needed. This paper discusses FDA/CDER's view on the opportunities and challenges of using NAMs in drug development especially for regulatory purposes, and also includes examples where NAMs are currently being used in nonclinical safety assessments and where they may supplement and/or enhance current testing methods. FDA/CDER also encourages communication with stakeholders regarding NAMs and is committed to exploring the use of NAMs to improve regulatory efficiency and potentially expedite drug development.