Preclinical predictors of clinical safety: opportunities for improvement.

Toxicology studies in animals are required by regulatory authorities worldwide to provide assurances that clinical testing of pharmaceutical candidates can be conducted safely. Safety concerns from animal studies account for over 20% of attritions from drug development. As discordance between humans and animals is expected, two goals of safe and efficient drug development must be (1) to improve the human relevance of animal testing with new models and technologies, and (2) to advance quickly to clinical testing armed with improved safety biomarker tools.