A Novel High-Throughput FLIPR Tetra Based Method for Capturing Highly Confluent Kinetic Data for Structure-Kinetic Relationship Guided Early Drug Discovery

Target engagement by small-molecules is necessary for producing a physiological outcome. In the past, a lot of emphasis was placed on understanding the thermodynamics of such interactions to guide structure-activity relationship. However, it is becoming clearer that understanding the kinetics of the interaction between a small molecule inhibitor and the biological target (structure kinetic relationship, SKR) is critical for selection of the optimum candidate drug molecule for clinical trial. However, the acquisition of kinetic data in high-throughput manner using traditional methods can be labor intensive, limiting the number of molecules that can be tested. As a result, in depth kinetic studies are often carried out only on a small number of compounds and, usually, at a later stage in the drug discovery process. Fundamentally, kinetic data should be used to drive key decisions much earlier in the drug discovery process but the throughput limitations of traditional methods precludes this. A major limitation that hampers acquisition of high-throughput kinetic data is the technical challenge in collecting substantially confluent datapoints for accurate parameter estimation from time-course analysis. Here we describe the use of Fluorescent Imaging Plate Reader (FLIPR), a CCD camera technology, as a potential high-throughput tool for generating biochemical kinetic data with smaller time-intervals. Subsequent to the design and optimization of the assay, we demonstrate the collection of highly confluent time-course data for various kinase protein targets with reasonable throughput to enable SKR-guided medicinal chemistry. We select kinase target 1 as a special case study with covalent inhibition and demonstrate methods for rapid and detailed analysis of the resultant kinetic data for parameter estimation . In conclusion, this approach has the potential to enable rapid kinetic studies to be carried out on 100's of compounds per week and drive project decisions with kinetic data at an early stage in drug discovery.