It is now well known that a significative CFTR-F508del’s recovery effect is possible by combining two correctors with complementary and synergistic mechanisms of action (eg. trikafta). The present study intends to follow the research line of the successful FFC#4/2018 project; researchers will work to identify molecules that display effective complementary action when associated to already known class 1 correctors. The goal is indeed to identify new third-generation CFTR correctors, belonging to the already known chemical group, namely PP molecules, which are very effective, not only in CF cells carrying the F508del mutation, but also on other CFTR variants, such as N1303K or stop mutations. The researchers intend to test the molecules for their pharmacological properties, in order to select good candidates to eventually be used in clinical trials, for alternative or possibly improved therapeutic combinations of modulators.