This is a single dose, open label study in adult male subjects with cystic fibrosis to investigate the pharmacokinetics, safety and tolerability of GLPG2737.

Inclusion Criteria:

• Male subject ≥18 years of age on the day of signing the informed consent form (ICF).
• A confirmed clinical diagnosis of CF.
• Two mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene belonging to class I and/or class II and/or class III (documented in the subject's medical record or CF registry).
• Weight ≥40 kg.
• Exocrine pancreatic insufficiency (documented in the subject's medical record).
• Stable concomitant medication regimen for at least 2 weeks prior to study drug administration.
• Forced expiratory volume in one second (FEV1) ≥40% of predicted normal for age, gender and height at screening (pre- or postbronchodilator).

Exclusion Criteria:

• History of clinically meaningful unstable or uncontrolled chronic disease that makes the subject unsuitable for inclusion in the study in the opinion of the investigator.
• Unstable pulmonary status or respiratory tract infection (including rhinosinusitis) requiring a change in therapy within 2 weeks prior to study drug administration.
• History of hepatic cirrhosis with portal hypertension (e.g.,signs/symptoms of splenomegaly, esophageal varices).
• Use of CFTR modulator therapy (e.g., lumacaftor or ivacaftor) within 2 weeks prior to study drug administration.