Central nervous system (CNS) disorders have long been the

Bermuda Triangle of drug development. For example, a 2014

study of Alzheimer’s disease (AD) drugs tested between

2002 and 2012 showed that 99.6% of them failed one of

Phase I, II or III trials. Many of these AD drugs failed late, in

large Phase III trials, making the failures costlier and more

dispiriting for researchers, drug developers, and, certainly,

patients. Rebecca M. Evans, MD, MS, Global Therapeutic

Area Head for CNS and her team at Parexel, serve the

readers with a detailed study of CNS drug development.