(R)-Posenacaftor ((R)-PTI-801) sodium, the R enantiomer of Posenacaftor, is a cystic fibrosis transmembrane regulator (CFTR) protein modulator. It corrects the folding and trafficking of the CFTR protein, and is utilized in the research of cystic fibrosis (CF)[1].

Cystic fibrosis (CF), an autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, results in defective and misfolded CFTR protein, disrupting ion flow across cell membranes. Posenacaftor, a CFTR corrector, repairs and restores CFTR function, enabling it to regulate fluid balance in the airways.