Ascletis Pharma Inc. announced that the China National Medical Products Administration (NMPA) has approved the Investigational New Drug (IND) application of ASC10 for monkeypox indication. ASC10 is an oral double prodrug. After oral administration, both ASC10 and single prodrug molnupiravir are rapidly and completely converted in vivo into the same active metabolite ASC10-A, also known as ß-D-N4-hydroxycytidine (NHC) or EIDD-1931.

Preclinical studies show that ASC10-A has broad spectrum antiviral activities including potent activities against both monkeypox and SARS-CoV-2 viruses. Ascletis has received the Notice of Issuance from the United States Patent and Trademark Office (USPTO) for the patent application of ASC10 and its derivatives, and their uses to treat multiple virus infections including SARS-CoV-2, monkeypox virus and respiratory syncytial virus (RSV). Ascletis is the first Chinese biotech company which has been granted a patent by the USPTO for its in-house developed oral viral polymerase inhibitor and its derivatives.

Monkeypox virus is an orthopoxvirus that causes a disease with symptoms similar to smallpox. As of January 25, 2023, over 85,106 confirmed cases have been reported globally and monkeypox virus has spread in 110 countries according to data from World Health Organization (WHO). Data from in vitro antiviral cellular assay with infectious monkeypox virus, a study sponsored by Ascletis and conducted at IIT Research Institute (IITRI) of Illinois Institute of Technology in Chicago, U.S., showed that ASC10-A has potent antiviral activity against monkeypox virus, suggesting that ASC10 has the potential to be an effective treatment of monkeypox virus infection.

In August 2022, researchers from National Institute of Infectious Diseases, Tokyo, Japan,tested 132 drugs and the results showed that molnupiravir (active metabolite ASC10-A) and other two drugs have potent cellular antiviral activity in the infectious monkeypox virus assay. The rest of 129 drugs such as remdesivir, favipiravir, sofosbuvir and ribavirin, etc. do not have antiviral activities against monkeypox virus.