The potentiator VX-770 (ivacaftor/KALYDECO™) targets defective gating of CFTR and has been approved for treatment of cystic fibrosis (CF) subjects carrying G551D, S1251N or one of 8 other mutations.
Both patients with the complex allele F508C-S1251N are carrying delta F508 on the other CF chromosome and are suffering from severe pulmonary and gastrointestinal CF disease.