CFTR and cystic fibrosis: Ivacaftor then acts to increase Cl– conductance in CFTR channels by increasing their open probability.166 The applications follow on from two successful phase 3 studies (TRAFFIC and TRANSPORT) that demonstrated significant and sustained improvement in lung function in people with the most common (F508del) form of cystic fibrosis.167 The opportunity and need for novel, effective ion channel modulators exists but now need to be matched with innovative design and discovery.