Identifying and validating novel targets with in vivo disease models: guidelines for study design.

In vivo studies are an important tool for the identification and validation of novel drug targets in medicine; however, the interpretation of submitted and published data is often compromised by inadequate study design. Different study protocols, including the number of control groups and group size calculations, differ in target identification and validation studies. Furthermore, animal studies require that the selected target or compound meets the requirements for species specificity and target specificity; thus, providing the rationale for the selection of a particular species, strain, gender and age of the animals is necessary. Altogether, the presentation of target validation studies should meet defined criteria similar to those used in human trials.