Chunk #13 — Problems of Successful Translation to Humans of Data from Animal Experimentation — The Discordance between Human Diseases and Animal Models of Diseases
In 2004, the FDA estimated that 92 percent of drugs that pass preclinical tests, including “pivotal” animal tests, fail to proceed to the market.38 More recent analysis suggests that, despite efforts to improve the predictability of animal testing, the failure rate has actually increased and is now closer to 96 percent.39 The main causes of failure are lack of effectiveness and safety problems that were not predicted by animal tests.40
