 Otherwise, genetic therapy will be used as a treatment when modulator therapies do not work given that 10% of people with cystic fibrosis are not effected by these drugs.Elexacaftor/ivacaftor/tezacaftor was approved in the United States in 2019 for cystic fibrosis.This combination of previously developed medicines is able to treat up to 90% of people with cystic fibrosis.