Résumé : Background: Respiratory syncytial virus (RSV) infection in lung transplant recipients is associated with high morbidity. This study evaluated the RSV fusion inhibitor presatovir in RSV-infected lung transplant recipients. Methods: In this international Phase 2b, randomized, double-blind, placebo-controlled trial (NCT02534350), adult lung transplant recipients with symptomatic confirmed RSV infection for ≤7 days received oral presatovir 200 mg on day 1 and 100 mg daily on days 2 to 14, or placebo (2:1), with follow-up through day 28. There were 2 coprimary endpoints: time-weighted average change in nasal RSV load from day 1 to 7, calculated from nasal swabs, in the full analysis set ([FAS]; all patients who received study drug and had quantifiable baseline nasal RSV load) and time-weighted average change in nasal RSV load from day 1 to 7 in the subset of patients with pretreatment symptom duration at the median or shorter of the FAS. Secondary endpoints were changes in respiratory infection symptoms assessed using the Influenza Patient-Reported Outcomes questionnaire and lung function measured by spirometry. Results: Sixty-one patients were randomized, 40 received presatovir, 20 placebo, and 54 were included in efficacy analyses. Presatovir did not significantly improve the primary endpoint in the FAS (treatment difference [95% CI], 0.10 [−0.43, 0.63] log10 copies/ml; p = 0.72) or the shorter symptom-duration subgroup (−0.12 [−0.94, 0.69] log10 copies/ml; p = 0.76). Secondary endpoints were not different between presatovir and placebo groups. Presatovir was generally well tolerated. Conclusions: Presatovir treatment did not significantly improve change in nasal RSV load, symptoms, or lung function in lung transplant recipients.