PG01 is a potent CFTR Cl- channel potentiator. PG01 can correct gating defects of CFTR mutants, is effective on b>E193K, G970R and G551D (CFTR mutants) with Kd values of 0.22 μM, 0.45 μM and 1.94 μM, respectively. PG01 is also effective on ΔF508 (Ka of 0.3 μM). PG01 increases ΔF508-CFTR Cl- current after adding Forskolin.