Key inclusion criteria:
* Cystic fibrosis (CF)-pulmonary phenotype and a confirmed diagnosis of CF:
* Positive sweat chloride ≥60 mmol/L by pilocarpine iontophoresis OR
* Genotype with 2 identifiable CF-causing mutations accompanied by one or more clinical features if sweat chloride testing is between 30 and 59 mmol/L
* Trial participants who are not eligible for treatment with cystic fibrosis transmembrane conductance regulator modulator therapy (CFTRmt) due to their genotype with 2 identified CFTR-mutations (including Class I CFTR gene mutations) and are also not expected to become eligible during the trial according to investigator´s opinion
* Trial participants able to perform acceptable spirometric maneuvers according to American Thoracic Society/European Respiratory Society 2019 standards
* Forced expiratory volume in 1 second, percent of predicted value (FEV1pp) ≥50% and ≤100% of predicted normal at Visit 1. Predicted value based on Global Lung Initiative lung function reference equations
* Stable CF disease with no pulmonary exacerbation 4 weeks prior to the screening visit and during the screening period and stable drug- and non-drug therapy for CF in the 4 weeks prior to dosing Further inclusion criteria apply.
Key exclusion criteria:
* Trial participants not eligible for CFTRmt based on contraindications (e.g. liver failure) or who needed to withdraw CFTRmt due to intolerability are not appropriate candidates for this Phase I/II trial
* Trial participants requiring chronic use of systemic corticosteroids or immunosuppressants to treat another condition Further exclusion criteria apply.
View Inclusion and Exclusion Criteria at ClinicalTrials.gov