Effects of EDP-938 in Hematopoietic Cell Transplant Recipients Infected With Respiratory Syncytial Virus of the Upper Respiratory Tract

Inclusion Criteria: * Received an autologous HCT (within 6 months of signing ICF) or an allogeneic HCT (any time) using any conditioning regimen * Absolute lymphocyte count (ALC) \<500 cells/ µL in allogeneic HCT recipients. Absolute lymphocyte count (ALC) \<300 cells/ µL in autologous HCT recipients. * Laboratory confirmed RSV diagnosis from a respiratory sample obtained within 3 days before signing the ICF. * New onset of at least one of the following respiratory symptoms within 3 days before signing the ICF: nasopharyngeal discharge, nasopharyngeal congestion, sneezing, sinus congestion, sore throat, hoarseness, earache, cough, shortness of breath, respiratory wheeze, or worsening of one of these symptoms if present chronically (associated with a previously existing diagnosis \[eg, chronic rhinorrhea, chronic lung disease\]) in the 3 days before signing the ICF or at Screening. * No evidence of new abnormalities consistent with LRTI on a chest imaging (chest x-ray and/or computed tomography) performed in the 2 days before signing the ICF or at the Screening visit if there is no chest X-ray and/or computed tomography available in the 2 days before signing the ICF. * Oxygen saturation \>95% on room air. * A woman of childbearing potential who is sexually active with a male must agree to use two effective methods of contraception from the date of Screening until 30 days after her last dose of study drug. * A male subject who has not had a vasectomy and is sexually active with a woman of childbearing potential must agree to use effective contraception from the date of Screening to 90 days after his last dose of study drug. Exclusion Criteria: * Admitted to the hospital primarily for a lower respiratory tract disease of any cause as determined by the Investigator. * Known to be concurrently infected with other respiratory viruses (eg, severe acute respiratory syndrome coronavirus 2 \[SARS-CoV-2\] or other coronavirus, influenza, parainfluenza, human rhinovirus, adenovirus, human metapneumovirus) within 7 days before signing the ICF, as determined by local testing. * Clinically significant viremia, bacteremia, or fungemia, or bacterial or fungal pneumonia within 2 weeks before signing the ICF that has not been adequately treated, as determined by the Investigator. * Known positive human immunodeficiency virus (HIV). * Any clinical manifestation resulting in QT prolongation.