Recent progress in biotechnology and basic immunology has led to the development of a broad range of novel vaccines raising exciting possibilities for the prevention of infectious diseases. Improvements to already licensed vaccines are also being considered; such improvements will lead to new products as well as to the introduction of new adjuvants. However, the complexity and novelty of these products presents scientific and regulatory challenges because criteria for their safety, potency and quality assessment may not exist. Product diversity and new approaches, technologies and methodologies develop over time; therefore, judgement based on the best science available should always form the basis for deciding on the type and extent of nonclinical evaluation for these products.
Although nonclinical evaluation plays an essential part in the overall development of vaccine candidates, there is at present limited guidance regarding nonclinical evaluation programmes for these products. In this guidance document, the general principles of nonclinical evaluation of vaccines are discussed, with particular attention being given to the regulatory expectations for new and novel vaccines.
Preclinical testing is a prerequisite to moving a candidate vaccine from the laboratory to the clinic and includes all aspects of testing, product characterization, proof of concept/immunogenecity studies and safety testing in animals conducted prior to clinical testing of the product in humans. Nonclinical evaluation, within the context of this document, refers to all in vivo and in vitro testing performed before and during the clinical development of vaccines. For example, nonclinical evaluation may be necessary when changes in the manufacturing process or product formulations are made or to further study potential safety concerns that may have arisen from phase I and II trials or that have been described in the literature for similar products.