Strategies to optimize the validity of disease models in the drug discovery process.

Models of human diseases are necessary for experimental research into the biological basis of disease and for the development of treatments. They have an enormous impact upon the success of biomedical research. However, in spite of this, a consistent system for evaluating, expressing and comparing the clinical validity of disease models is not available. The purpose of this paper is, therefore, to provide a theoretical discussion of the concepts behind disease models and to develop a terminology and a framework to analyze and express the clinical validity of disease models.