New CF Combo Therapy, Symdeko by Vertex, Approved by FDA for Certain Patients Vertex Pharmaceuticals announced that the U.S. Food and Drug Administration (FDA) approved Symdeko (tezacaftor/ivacaftor and ivacaftor) as a therapy for cystic fibrosis (CF) patients carrying two copies of the F508del mutation in the CFTR gene (the gene defective in CF) or with one mutation that responds to tezacaftor/ivacaftor.