Calista Therapeutics are developing medications that target the underlying Cystic Fibrosis protein. These are peptides that are currently in pre-clinical studies.
The lead candidate is Procaftor, which is a peptide that helps F508del CFTR function. Based on the links below about Procaftor, I believe Procaftor potentially improves trafficking, function and stability of the F508del protein (by modulating PDZ interactions). Pre-clinical studies have shown clinical efficacy with no signs of toxicity. It is planned that Procaftor would come as a powder, inhaled through a nebuliser once a day. It potentially could be used with other medications. This medication is at least six years away from potential regulatory approval (according to the article below about Calista Therapeutics).
“Procaftor penetrated the mucus and induces a 116% improvement in CFTR chloride current with a duration of effect >25 hrs”
The second candidate is Calcaftor, which targets CFTR through a different mechanism. This is also in pre-clinical development.
Calista Therapeutics are working with the Cystic Fibrosis Foundation and are currently looking for funding for the phase 2a trial. According to the article below, the CEO of Calista Therapeutics stated that “with peptide drugs, you can do a lot more design and a lot less testing,” and the article suggested that peptide drugs allow for relatively cheap production of large quantities. Calista Therapeutics are also planning to seek Orphan Drug Designation for Procaftor.