Triple potentiator combinations increase the functional correction of several CFTR gating mutants

The Trikafta drug combination, comprising the corrector tezacaftor (VX-661), the potentiator ivacaftor (VX-770) and the dual corrector/potentiator elexacaftor (VX-445), has been FDA-approved for treatment of cystic fibrosis caused by ~300 cystic fibrosis transmembrane conductance regulator (CFTR) mutations. Nevertheless, several CFTR variants exhibit limited response to Trikafta. To address this therapeutic gap, we investigated whether the potentiator activity of VX-445 can complement the VX-770 and preclinical "co-potentiators" activity in partially responsive CFTR mutants. Functional clustering of clinical and preclinical potentiator profiles suggests that VX-445 represents a distinct potentiator class, an inference supported by its additivity with both VX-770/VX-770-like potentiators and co-potentiators across five CFTR mutants in bronchial epithelia. This concept was further validated in gene-edited 16HBE and primary human nasal epithelia, expressing G551D-, N1303K-, and W1282X-CFTR, the 3rd, 4th, and 6th most common CF-mutations, respectively, and was confirmed at the single-channel level. Moreover, we present the development of a novel series of co-potentiator compounds that are derived from our previously described 4172 corrector scaffold, which exhibit low micromolar potency. Our findings suggest that triple potentiation can significantly enhance functional restoration of poorly responsive gating mutants, thereby uncovering novel avenues for therapeutic development.