Proteostasis Therapeutics Inc., of Cambridge, Mass., disclosed positive study results across all three of the company's cystic fibrosis (CF) pipeline programs. Those include a study in CF subjects for PTI-428, a cystic fibrosis transmembrane conductance regulator (CFTR) amplifier; interim data for a study in CF subjects for PTI-801, a new generation CFTR corrector; and studies in healthy volunteers for PTI-808, a CFTR potentiator, and the combination of PTI-428, PTI-801 and PTI-808.