A Nontoxin Aminopyrimidine Probe for Near State-Independent NaV1.7 Inhibition

Abstract

Abstract The voltage-gated sodium channel NaV1.7 is among the most compelling genetically validated pain targets; however, advanced small-molecule inhibitors, including voltage-sensing domain IV (VSD4)-directed series, have not yet achieved robust clinical efficacy, potentially reflecting pharmacological limitations such as pronounced state dependence. Here, we report a nontoxin aminopyrimidine series that serves as a differentiated pharmacological probe for near state-independent NaV1.7 inhibition. Using a high-throughput automated patch clamp screening cascade designed to deprioritize established local anesthetic pore binders, we identified hit 1 and optimized it to compound 6, which combines balanced resting- and inactivated-state potency (IC50 = 1.00 and 0.45 μM, respectively). It displays a 29-fold selectivity margin over NaV1.5 and a tetrodotoxin (TTX)-like isoform profile that includes comparable activity on NaV1.7 and NaV1.1. Structure–activity studies identified the aminopyrimidine core and methylene-linked aniline motif as key determinants of this profile, while NaV mutant profiling supports a functional fingerprint consistent with pore-proximal modulation distinct from VSD4-directed inhibition.