Profiling and Optimizing Targeted Covalent Inhibitors through EGFR-Guided Studies

Targeted covalent
inhibitors (TCIs) are actively pursued in drug
discovery due to their prolonged target engagement and clinical efficacy.
Although kinetic parameters provide a path to their optimization,
systematic design strategies and practical guidance remain underexplored.
In this study, the EGFR kinase is deployed as a model system to elucidate
structural and functional determinants critical for directing the
optimization of irreversible TCIs. Functional analyses reveal a two-phase
optimization process, underscoring the importance of balancingrather
than maximizingthe inactivation efficiency rate (kinact/KI). Selective inhibition
of the oncogenic L858R/T790M mutant over the wild-type is achieved
by tuning this balance, particularly for TCIs exhibiting the fastest kinact/KI. Structural
studies indicate that certain hydrophobic and hydrophilic interactions
are associated with L858R/T790M selectivity, offering insights into
structure-guided design. These results offer a broadly applicable
approach for prioritizing compounds and support the integration of
kinetic and selectivity data in TCI discovery campaigns.