EIDD-2749 (4'-Fluorouridine) is an orally active RdRp inhibitor. EIDD-2749 effectively blocks the replication of RSV and SARS-CoV-2 . EIDD-2749 also exhibits activity against HCV and lymphocytic choriomeningitis virus ( LCMV ). EIDD-2749 is a promising oral therapeutic candidate for COVID-19 and is also suitable for research on other RNA viruses In Vitro EIDD-2749 induces a delayed stalling of phosphodiester bond formation by RSV and SARS-CoV-2 RdRP. EIDD-2749 is rapidly anabolizes, metabolically stable, and potently antiviral in disease-relevant well-differentiated HAE cultures. EIDD-2749 shows a ≥17-fold increase in anti-RSV potency relative to that on HEp-2 cells; however, the low cytotoxicity levels remains unchanged (CC 50 169 mM), resulting in a high SI (SI = EC 50 /CC 50 ) of ≥1877. EIDD-2749 inhibits SARS-CoV-2 with an EC 50 value of 0.2-0.6 M. EIDD-2749 has an EC 50 of 1.86 μM in theVero E6 cell line, cytotoxicity with a CC 50 of 380 μM, and stability in human plasma. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo EIDD-2749 (0.2, 1, 5 mg/kg; p.o.; single daily for 4 days) shows good orally efficacious in RSV infection mice model in a dose-dependent manner . EIDD-2749 shows high efficacious to SARS-CoV-2 infection and is effective with a single daily dose versus molnupiravir administered twice daily in vivo. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Animal Model: Balb/cJ mice (RSV infection model) . Dosage: 0.2, 1, 5 mg/kg Administration: Oral administration; single daily for 4 days Result: Resulted in a statistically significant reduction in lung virus load. Form:Solid IC50& Target:RdRp, RSV,SARS-CoV-2, HCV, COVID-19, LCMV, .