Ascletis Announces Positive Interim Data from the Phase IIb Expansion Cohort of ASC22 (Envafolimab) for Chronic Hepatitis B Functional Cure

HANGZHOU and SHAOXING,China,Sept. 29,2023 -- Ascletis Pharma Inc. (HKEX: 1672,"Ascletis") today announces positive interim data from the Phase IIb expansion cohort (the "Expansion Cohort") of subcutaneously administered PD-L1 antibody ASC22 (Envafolimab) for functional cure of chronic hepatitis B (CHB).

The Expansion Cohort is a randomized,single-blind,placebo-controlled and multi-center clinical trial (ClinicalTrials.gov: NCT04465890) and planned to enroll approximately 50 CHB patients with baseline hepatitis B surface antigen (HBsAg) ≤100 IU/mL who would be treated with 1.0 mg/kg ASC22 or placebo (at a ratio of approximately 4:1) once every two weeks (Q2W) for 24-week treatment plus 24-week follow-up. All patients in both ASC22 and placebo cohorts received nucleot(s)ide analogues (NAs) as a background therapy. In the second quarter of 2023,Ascletis successfully completed the enrollment of 49 CHB patients,including 40 patients in ASC22 cohort and 9 patients in placebo cohort.

Interim analysis was conducted when approximately 50% of the enrolled patients completed 24-week treatment of ASC22 or placebo. The interim analysis included 25 patients who completed 24-week treatment (19 patients in ASC22 cohort and 6 patients in placebo cohort). Topline results indicated that in ASC22 cohort,4 patients (4/19,21.1%) achieved HBsAg loss at the end of 24-week treatment. In contrast,there were no patients (0/6,0%) achieving HBsAg loss at the end of 24-week treatment in the placebo cohort. ASC22 was generally safe and well tolerated. Most of ASC22 drug related adverse effectswere Grade 1 or 2.

CHB remains to be a significantly unmet medical need globally,with approximately 86 million people in China and 1.59 million people in the U.S. infected with hepatitis B virus (HBV)[1].

"While pursuing Phase IIb clinical study of ASC22 (Envafolimab) as monotherapy for CHB patients with baseline HBsAg≤100 IU/mL,we are also engaging global partners to discuss collaboration on combo therapies to achieve higher functional cure rates for HBV." said Dr. Jinzi J. Wu,Founder,Chairman and CEO of Ascletis.

[1]LimJK,NguyenMH,KimWR,etal.PrevalenceofChronicHepatitisBVirusInfectionintheUnitedStates[J].TheAmericanjournalofgastroenterology 2020,115(9):1429-38.

About AscletisAscletis 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 multiple drug candidates in its R&D pipeline. The most advanced drug candidates include ASC22 (CHB functional cure),ASC40 (acne),ASC40 (recurrent glioblastoma),ASC40 (NASH),ASC41 (NASH) and ASC61 (advanced solid tumors).For more information,please visitwww.ascletis.com.