In a phase I trial, treatment with EIDD-2801 was well tolerated in patients with COVID-2019 infection   .
In preclinical studies, oral administration of EIDD 2801 resulted in decreased group pandemic 1 and group 2 seasonal influenza A shed virus load by multiple orders of magnitude and alleviated fever, airway epithelium histopathology, and inflammation. In disease-relevant well-differentiated human air-liquid interface airway epithelia, inhibitory concentrations were low nanomolar against influenza A and B viruses. A therapeutic window >1713 was observed and dosing parameters required for efficacious human therapy was established when antiviral efficacy and cytotoxicity thresholds with pharmacokinetic profiles in human airway epithelium models were correlated  .
In animal models infected with Severe acute respiratory syndrome (SARS)/ Middle East respiratory syndrome coronavirus (MERS) treatment with EIDD 2801 led to therapeutic benefits. In models with (SARS-CoV1 and MERS), EIDD 2801 improved pulmonary function, decreased body weight loss and reduced the amount of virus in the lung. The candidate also prevented significant manifestations of disease following prophylactic administration in animals challenged with MERS and SARS  .