Ascletis Presented Positive Phase I Clinical Data for Broad-Spectrum Antiviral Double Prodrug ASC10 at CROI 2023

--At the dosage of 800 mg ASC10,twice daily (BID),the exposure of the active drug,ASC10-A,is comparable to that of monupiravir's

--ASC10 at 800 mg,BID is safe and well tolerated

--Dosage of 800 mg ASC10,BID was selected for Phase IIa clinical trial for respiratory syncytial virus (RSV) infection in the U.S. and Phase III clinical trial for SARS-CoV-2 infection in China

HANGZHOU and SHAOXING,China,Feb. 21,2023 --AscletisPharma Inc. (HKEX: 1672,"Ascletis") today presented positive data from Phase I clinical trial of ASC10,a broad-spectrum antiviral double prodrug,at Conference on Retroviruses and Opportunistic Infections (CROI) 2023 in Seattle,the U.S.

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 drug ASC10-A,also known as β-D-N4-hydroxycytidine (NHC) or EIDD-1931.

Preclinical studies show that ASC10-A has broad-spectrum antiviral activities including potent activities against both SARS-CoV-2 viruses,monkeypox and respiratory syncytial virus (RSV).

Results from the Phase I clinical trial showed at the dosage of 800 mg ASC10,is comparable to that of monupiravir's. ASC10 was safe and well tolerated,and the increase in plasma exposure of ASC10-A was dose-proportional across the range of doses tested (50 mg to 800 mg) with no accumulation and minimal food effect. Dosage of 800 mg ASC10,twice daily was selected for Phase IIa clinical trial for RSV infection in the U.S. and Phase III clinical trial for SARS-CoV-2 infection in China.

Ascletis has been granted the patent of ASC10 and its derivatives,and their uses to treat multiple virus infections including SARS-CoV-2,monkeypox virus and RSV from the United States Patent and Trademark Office (USPTO). 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.

About CROI

The Conference on Retroviruses and Opportunistic Infections (CROI) was established in 1993 to facilitate academic exchange in the epidemiology and biology of human retroviruses and associated diseases. CROI features the best and most consequential original research in human immunodeficiency virus (HIV),hepatitis viruses,SARS-CoV-2,monkeypox virus,and other viral infections and their related conditions. The CROI 2023 will be held in Seattle,Washington,the U.S. from February 19 to 22,2023.

About Ascletis

Ascletis is an innovative R&D driven biotech listed on the Hong Kong Stock Exchange (1672.HK),covering the entire value chain from discovery and development to manufacturing and commercialization. Led by a management team with deep expertise and a proven track record,Ascletis focuses on three therapeutic areas with unmet medical needs from a global perspective: viral diseases,non-alcoholic steatohepatitis (NASH) and oncology. Through excellent execution,Ascletis rapidly advances its drug pipeline with an aim of leading in global competition. To date,Ascletis has three marketed products,i.e. ritonavir tablets,GANOVO® and ASCLEVIR®,and 23 drug candidates in its R&D pipeline. The most advanced drug candidates include ASC22 (HBV functional cure),ASC10 and ASC11(oral small molecules for COVID-19 treatment),ASC40 (recurrent glioblastoma),ASC42 (PBC,primary biliary cholangitis),and ASC40 (acne).

For more information,please visit www.ascletis.com.