It is currently well accepted that in general, more than one method is necessary to allow the full replacement of an animal experimentation. These so called partial replacement methods can be used within integrated strategy approaches that combine different methods and information sources. A number of integrated strategy approaches were implemented within recent years in different areas of safety and regulatory toxicology.
Moreover, latest advances in biomedical research and bioengineering provide a major opportunity to make use of in vitro human-based and/or three-dimensional complex models that can contribute to achieve more physiologically-relevant models. Examples herein describe currently existing integrated strategy frameworks aiming at full or partial replacement purposes and/or at gaining mechanistic insights. Furthermore, a general concept is provided on how 3R methods might be integrated in a strategy approach in order to ensure that animal experimentation is conducted only as a last resort.