I1421

I1421 is an activator of the cystic fibrosis transmembrane conductance regulator (CFTR), with an EC50 of 64 nM for WTCFTR currents. It also allosterically activates various CF-causing mutants, demonstrating good in vivo efficacy with an oral bioavailability of 60% in mice and a corresponding half-life of 75 minutes. I1421 works synergistically with Elexacaftor to enhance CFTR currents.