A Master Protocol to Test the Impact of Discontinuing Chronic Therapies in People with Cystic Fibrosis on Highly Effective CFTR Modulator Therapy (SIMPLIFY)

This master protocol is designed to evaluate the independent effects of discontinuing hypertonic saline (Study A) and dornase alfa (Study B) in people with cystic fibrosis (CF) age 12 and older currently taking the highly effective modulator elexacaftor/tezacaftor/ivacaftor (ETI). Study A and Study B are identical open label two-arm randomized trials consisting of a 2-week screening period, randomization to continue or discontinue hypertonic saline (Study A) or dornase alfa (Study B), followed by a 6-week study period. Subjects taking only hypertonic saline (HS) or dornase alfa at trial entry will be randomized 1:1 to either continue or discontinue the applicable therapy (i.e. HS or dornase alfa). Subjects taking both hypertonic saline and dornase alfa at study entry will be randomized to participate in either Study A or Study B and will be randomized (1:1) to continue or discontinue the applicable therapy (i.e. HS or dornase alfa). After completion of the first study, eligible subjects may subsequently enroll in the alternative study. Clinical outcomes (forced expiratory volume in 1 second [FEV1], antibiotic use, pulmonary exacerbations, and patient reported outcomes), safety (adverse events) and the subject’s perception of how stopping HS or dornase alfa (or both) would impact their daily life will be evaluated in all subjects. Additional outcome measurements will be conducted in a subset of subjects at selected study sites: • Multiple Breath Washout (MBW) to evaluate changes in lung clearance index (LCI) • Mucociliary Clearance (MCC) using inhaled radio-labeled particles to evaluate changes in mucociliary clearance