Hangzhou and Shaoxing, China, November 23, 2022--Ascletis Pharma Inc. (HKEX: 1672, “Ascletis”) announces today that the U.S. Food and Drug Administration (FDA) has approved the Investigational New Drug (IND) application of ASC11, an oral inhibitor drug candidate targeting 3-chymotrypsin like protease (3CLpro) for COVID-19.

U.S. FDA has approved to study safety, tolerability and pharmacokinetics of ASC11 at various doses in healthy subjects co-dosed with 100 mg ritonavir tablets. Both ASC11 and ritonavir tablets are manufactured by Ascletis.

The Phase I clinical trial will consist of 3 cohorts in healthy subjects, including single- and multiple-dose escalation studies and food effect study. The objective of Phase I trial is to find a right dose to move into the pivotal Phase II/III in COVID-19 patients.

In antiviral cellular assays with infectious SARS-CoV-2, ASC11 demonstrated much higher potency against SARS-CoV-2 than other 3CLpro inhibitors including Nirmatrelvir, S-217622, PBI-0451 and EDP-235. ASC11 remains potent antiviral activity against various popular Omicron variants such as BA.1 and BA.5. In the animal model with infectious SARS-CoV-2, ASC11 also showed potent antiviral activity.

ASC11 is an in-house discovered oral small molecule drug candidate using various proprietary technologies including molecular docking. Ascletis has filed global patent applications for ASC11 and related compounds and their use in viral disease.

"In addition to safety data, this Phase I trial will confirm whether ASC11 needs to be boosted with ritonavir or not,” said Dr. Jinzi J. Wu, Founder, Chairman and CEO of Ascletis, “We are excited that our proprietary COVID-19 pipeline, including ASC10 (RdRp inhibitor) and ASC11 (3CLpro inhibitor), have all entered into clinical development in the U.S., which marks a great recognition to our in-house R&D capabilities. As COVID-19 pandemic causes persistent huge social and economic implications globally, Ascletis is dedicated to leveraging our global clinical development expertise in viral diseases to fight against the pandemic."

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 22 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.

Contact：

Ascletis Pharma Inc.

+86-181-0650-9129

pr@ascletis.com

ir@ascletis.com