In drug discovery, it is essential to accurately measure drug-target binding affinity. Here, we revisit the fact that target binding kinetics impact the measurement of affinity, using a case study: development of corticotropin-releasing factor antagonists. Slow dissociation of the drug-target complex results in affinity assays being far from equilibrium, which results in erroneous estimates of affinity. This scenario can impair prediction of human dosing, assessment of target selectivity, identification of high-affinity ligands and determination of SAR. We describe strategies to detect lack of equilibration in affinity assays and methods to correctly measure affinity of slowly dissociating compounds. These considerations will facilitate drug discovery by ensuring reliable measurement of drug-target binding affinity.
Copyright © 2019 Elsevier Ltd. All rights reserved.