PTI-721

PTI-721 is an investigational small molecule CFTR corrector developed by Proteostasis Therapeutics for the treatment of cystic fibrosis (CF). It functions as a pharmacological chaperone designed to address the underlying protein folding defect in the cystic fibrosis transmembrane conductance regulator (CFTR) protein, specifically the F508del mutation. By assisting in the proper folding and stability of the mutant CFTR protein within the endoplasmic reticulum, PTI-721 facilitates its trafficking to the cell surface. Once at the plasma membrane, the restored CFTR protein can function as a chloride channel, helping to alleviate the thick mucus accumulation characteristic of the disease. PTI-721 was primarily developed to be part of a next-generation triple combination regimen, often studied alongside other CFTR modulators like amplifiers and potentiators to maximize therapeutic efficacy.