Tezacaftor is used in the treatment of cystic fibrosis, a genetic disorder that affects the lungs and other organs. It works by helping the defective CFTR protein function more normally, specifically in patients who have certain mutations in the CFTR gene. When combined with other medications like ivacaftor, tezacaftor improves lung function, reduces the frequency of respiratory flare-ups, and helps maintain better overall health. The therapy is taken orally and is part of a class of drugs known as CFTR modulators, which target the underlying cause of cystic fibrosis rather than just managing symptoms. It is particularly effective for patients with at least one F508del mutation, one of the most common CFTR mutations.