Pre-clinical data:
Therapeutic efficacy was first demonstrated by suppressing viral replication in Ebola infected infected rhesus monkeys. Prophylactic use was initiated 24 h prior to viral challenge, whereas therapeutic use was initiated 12 h after challenge. The severity of pulmonary infiltrates, were significantly better in the prophylactic and therapeutic groups, comparing each to controls.[4] Efficacy studies in Ces1c−/− mice demonstrated therapeutic efficacy of this drug against Severe Acute Respiratory Syndrome (SARS)-CoV and Middle East Respiratory Syndrome coronavirus (MERS-CoV). Sheahan et al. found that both prophylactic and therapeutic remdesivir had protective effects against MERS-CoV replication and associated pathology, generally resulting in less lung damage and better pulmonary function.[5] In 2018, Murphy et al. examined the efficacy of this drug against Feline infectious peritonitis (FIP) in 12 experimentally infected cats. In the 10 infected cats, treatment was initiated ( 5 cats with 5mg/kg daily and 5 cats with 2mg.kg daily) upon onset of FIP-associated clinical signs and continued for 2 weeks. All treated cats demonstrated favorable responses to remdesivir treatment within 24–48 h.[6] Pedersen et al. treated 31 cats with an initial dose of 2 mg/kg daily. A total of 25 treated cats (81%) survived FIP for at least 44 weeks of follow up, indicating that this drug is also a promising therapeutic candidate for treatment of alphacoronavirus- related disease in cats. This study was done on cats with naturally occurring CoV infection, representing real world situation.[7] Efficacy of this drug was also tested against Nipah virus Bangladesh genotype among African green monkeys and it showed all remsdesivir-treated animals survived and mild respiratory signs were observed in two out of four treated animals.[8] It also exhibited antiviral activity in vitro against other virues like Marburg virus,Paramyxoviridae (such as parainfluenza type 3 virus, Nipah virus, Hendra virus, and measles and mumps viruses) and Pneumoviridae (such as respiratory syncytial virus).[9] Wuhan Virus Research Institute carried out a vitro inhibition test and found that remdesivir can block virus infection at very low micromolar concentration of Vero E6 cells infected with virus, and the cell selectivity is high (EC50 = 0.77 μM, CC50 > 100 μM, SI > 129.87). It draws a speculation that it could also play a role (EC90 =1.76 μΜ) in SARS-CoV-2 infected monkeys.[10] Preclinical studies are compiled in Table 1.