However, Proteostasis Therapeutics have recently announced that in a phase 1/2 clinical study where neosolicaftor was tested in combination with the CFTR modulators posenacaftor (PTI-801) and dirocaftor (PTI-808) (NCT03500263), there was an ~8% increase in ppFEV1 in CF adults homozygous for F508del. This evidence concerns the gene CFTR and cystic fibrosis.