Due to the complex nature of the conditions they are developed to treat, central nervous system - or CNS - drugs face greater development challenges compared to non-CNS drugs, due in large part to our poor understanding of the underlying pathophysiology of many of the disorders, as well as difficulty identifying and measuring appropriate clinical endpoints. As a result, CNS drugs typically spend more time in clinical development and regulatory review, and they experience lower approval rates, compared to non-CNS drugs. Despite these challenges, CNS drug approvals by the FDA as a share of all drug approvals not only has remained relatively steady over nearly four decades, but has increased slightly over that time.
The opportunity and challenge for drug developers is clear. Opportunities arise from the estimate that CNS disorders will constitute nearly 15% of the global disease burden by 2020. The challenges are to decrease development time and increase success rates without sacrificing safety, while simultaneously reigning in overall development costs. This report summarizes a recent Tufts CSDD analysis of 509 drugs and biologics that received FDA approval from 2000 to 2017.