Cystic Fibrosis FEV1 Decline and CFTR Modulators

A 12-year-old boy with cystic fibrosis (CF) due to homozygous F508del CFTR mutations presents for routine pulmonary assessment. Spirometry shows FEV1 of 65% predicted with a flow-volume loop pattern marked **A** in the diagram. His sweat chloride is 98 mEq/L (normal <30). He has been on standard CF therapy (airway clearance, inhaled tobramycin, dornase alfa) for 2 years with an annual FEV1 decline of approximately 2% per year. His parents ask about newer treatment options. Which of the following best describes the therapeutic mechanism of elexacaftor/tezacaftor/ivacaftor (TRIKAFTA) that would improve the obstructive pattern seen in structure **A**?