Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) is the newest CFTR modulator approved for patients with cystic fibrosis. In randomized controlled trials, ELX/TEZ/IVA showed benefit at 24 weeks in terms of lung function, respiratory symptoms, pulmonary exacerbations and weight. However, long-term clinical benefit of ELX/TEZ/IVA in real-world settings is still being investigated. Methods This retrospective within-groups study examined cystic fibrosis patients receiving care from a single academic health-system specialty pharmacy. Subjects were included who initiated ELX/TEZ/IVA and continued therapy for greater than one year. Retrospective data from the index year prior to ELX/TEZ/IVA initiation and the year following was collected by medical records review. The primary end point was the difference in number of severe cystic fibrosis exacerbations in index year as compared to the year post ELX/TEZ/IVA initiation. Results A total of 76 patients were included in the final analysis. In the post- ELX/TEZ/IVA year, subjects had a significant mean decrease in severe exacerbations (-0.72; 95% CI -0.43, -1.02; p<0.0001). Decreases in severe exacerbations remained significant in subgroups of patients with prior CFTR exposure (-0.56; 95% CI -0.22, -0.91; p =0.002; n=46) and moderate to severe lung disease (-0.98; 95% CI -0.49, -1.45; p = 0.0002; n=41). After one year of ELX/TEZ/IVA therapy, subjects experienced a significant mean absolute increase in ppFEV1 of 6.07% (between-years difference 4.47%; 95% CI 0.58, 8.37; p=0.025) and increase in BMI of 1.46 (between-years difference 1.29; 95% CI 0.65, 1.95; p=0.0002). Conclusion One year of ELX/TEZ/IVA therapy was associated with sustained improvements in clinical status of cystic fibrosis patients.