https://www.sciencedaily.com/releases/2020/01/200127134724.htm

Part of the problem lies in the imperfect nature of preclinical drug testing that aims to exclude toxic effects and predetermine concentrations and administration routes before drug candidates can be tested in people. How new drugs move within the human body and are affected by it, and how drugs affect the body itself, cannot be predicted accurately enough in animal and standard in vitro studies.

"To solve this massive preclinical bottleneck problem, we need to become much more effective at setting the stage for drugs that are truly promising and rule out others that for various reasons are likely to fail in people," explains Prof. Donald Ingber, M.D., Ph.D., founding director of Harvard University's Wyss Institute for Biologically Inspired Engineering, co-author of two new studies on the subject published in Nature Biomedical Engineering on January 27, 2020.