Nelfinavir inhibits replication of severe acute respiratory syndrome coronavirus 2 in vitro.

Norio Yamamoto; Shutoku Matsuyama; Tyuji Hoshino; Naoki Yamamoto

As of now, no specific treatment has been established against coronavirus disease-2019 . After the outbreak of severe acute respiratory syndrome (SARS) in 2003, screening of approved drugs identified at least two human immunodeficiency virus type-1 (HIV-1) protease inhibitors, lopinavir and nelfinavir, as compounds that inhibited SARS-CoV replication in vitro 3, 4 . In the open-label study with SARS patients in 2004, the group treated with lopinavir-ritonavir (400 mg and 100 mg, respectively) in addition to ribavirin showed better clinical outcomes than the control group treated with only ribavirin 3 . Because SARS-CoV-2 is relatively similar to SARS-CoV 5 , it is expected that these drugs will be effective for the treatment of COVID-19 patients. To select the candidate drug for the clinical evaluation, the data of antiviral activity in vitro are of great help. However, there is no basic information about the effective concentration of HIV-1 protease inhibitors to abrogate SARS-CoV-2 replication. Thus, in the present study, we evaluated the antiviral activity of nine approved HIV-1 protease inhibitors against SARS-CoV-2 in vitro.