Three Pillars of Early Drug Discovery Success: Part 1: Introduction to druggability, ligandability, and assayability

This white paper introduces a framework for evaluating early drug discovery programs through three interconnected pillars: druggability, ligandability, and assayability. It defines druggability as the likelihood that a target can be modulated by a therapeutic molecule, ligandability as the ability to identify compounds that bind to that target, and assayability as the ability to reliably measure the target’s biological activity. The paper argues that while druggability and ligandability are often assessed early, assayability is frequently treated as a downstream consideration, creating avoidable bottlenecks in screening and lead optimization. By evaluating assayability in parallel with the other two pillars, organizations can identify technical risks sooner, accelerate decision-making, and improve the overall efficiency and success rate of discovery programs.