Animal toxicology studies on new medicines and their relationship to clinical exposure: a review of international recommendations.

Written guidance on the toxicology studies which should be completed to support an application to market a new medicinal product in the EEC, Japan, and the USA is readily available, although the recommendations can vary significantly between the three markets. Less clear are the regulatory authorities' expectations concerning the timing of these studies relative to the clinical development programme. All available guidelines for premarketing toxicology requirements, and the portions thereof needed to support various stages of the clinical trials programme will be reviewed. Significant differences among the three markets and between written guidance and customary practice will be highlighted. The practical implications for the clinical development programme will be identified.