CFTR and cystic fibrosis: To date, In the US the combination of elexacaftor/tezacaftor/ivacaftor (TRIKAFTATM) is a prescription medicine used for the treatment of cystic fibrosis (CF) in patients aged 6 years and older who have at least one copy of the F508del mutation in the CFTR gene or another of 177 mutations that are responsive in vitro to treatment with TRIKAFTA.