Currently, a Phase 2 clinical trial (the TOPIC trial), aiming to establish the safety and efficacy of ivacaftor in COPD patients with chronic bronchitis and acquired CFTR dysfunction as detected by sweat chloride analysis, is recruiting patients (ClinicalTrials.gov Identifier: NCT03085485 (accessed on 30 July 2021)). This evidence concerns the gene CFTR and chronic obstructive pulmonary disease.