RecruitingEarly Phase 1Drug trialIvacaftor for Acquired CFTR Dysfunction in Chronic RhinosinusitisThe purpose of this pilot study is to explore wither ivacaftor in refractory CRS patients will demonstrate safety and tolerability; restore CFTR-mediated Cl- secretions as measured by EDSPD testing; produce detectable improvements in validated measures of CRS including the SNOT-22 questionnaire, Lund-MacKay CT scan grading, and Lund-Kennedy endoscopic scores; and provide beneficial effects on readily measured markers of sinonasal inflammation and infection (IP-10, IL-8, and Pseudomonas CFUs).