There is an enormous chemical universe of small-molecule compounds—an estimated 10 to the 33rd power (or a billion trillion trillion) molecules—that can be manufactured using organic chemistry. Trillions of these molecules could lead to therapeutic advances. But due to the size of this chemical universe, brute-force exploration of its contents is doomed to failure because synthesis is time-consuming and resource-intensive. Another strategy is needed.

The goal of modern drug discovery is to develop medications that are safely administered with minimal side effects while strongly binding to disease-associated proteins in our bodies. And yet despite a growing list of validated target proteins in the wake of the Human Genome Project, the rate of new FDA approvals for novel small-molecule drugs has stagnated over the past 15 years.