Study ID number: PTI-428-01 
Official Title: A Phase I/II, Multi-center, Randomized, Placebo-Controlled, Study Designed to Assess the Safety, Tolerability, and Pharmacokinetics of PTI-428 in Subjects With Cystic Fibrosis
Therapeutic Category: CFTR modulator 

PTI-428 is a CFTR “amplifier” that was designed to help increase the amount of CFTR protein being made by the cell. In CF, there is a mutation in the CFTR gene which makes the proteins unstable after they are made. This causes them to break down and be unable to reach the cell surface to create a channel. This channel is important in maintaining proper water and salt balance that keeps the mucus thin and not sticky. 

This was the first time PTI-428 was given to subjects with CF. It was given to those who are deltaF508 homozygous (have 2 copies) or heterozygous (have at least 1 copy and 1 CF causting mutation). The study was done to learn more about the safety and tolerability of PTI-428 when given to subjects with CF. This also looked at how PTI-428 may affect your body and how your body breaks down and eliminates the drugs over a 7 or 28 day treatment period.    

The study was completed and proceeded to further trials. 

Source: ClinicalTrials. gov: