Oral Presentation at APASL Annual Meeting 2023 Demonstrates ASC22, a Subcutaneous PD-L1 Antibody, Can Achieve Functional Cure of Chronic Hepatitis B

HANGZHOU and SHAOXING,China,Feb. 16,2023 --Ascletis Pharma Inc. (HKEX:1672,"Ascletis") today announces that the oral presentation at the 2023 annual meeting of the Asian Pacific Association for the Study of the Liver ("APASL Annual Meeting 2023") demonstrates that ASC22 (Envafolimab),a subcutaneous PD-L1 antibody,can achieve functional cure of chronic hepatitis B (CHB).

The final data of 1.0 mg/kg ASC22 (administered subcutaneously once every two weeks) vs placebo cohort (ClinicalTrials.gov: NCT04465890) were presented today at APASL Annual Meeting 2023. In this cohort,48 patients completed 24-week treatment of 1.0 mg/kg ASC22 and 24-week or longer follow-up; 15 patients completed 24-week treatment of placebo and 24-week follow-up. 24-week treatment of ASC22 resulted in remarkable HBsAg decline. In the patient sub-group with baseline HBsAg ≤100 IU/mL,42.9% (3/7) of patients achieved HBsAg loss (HBsAg below the lower limit of quantification,LLOQ < 0.05 IU/mL) during the treatment and HBsAg loss maintained at the completion of 24-week or 41-week follow-up,indicating that ASC22 achieved CHB functional cure in these patients. The CHB functional cure is in general defined as achieving HBsAg loss with a finite treatment duration (typically 24 to 48 weeks) and HBsAg loss still maintains after at least 24-week follow-up.

The data further indicated that HBsAg reduction upon ASC22 treatment was statistically correlated with patients' baseline (pre-treatment) HBsAg levels. Compared to patient sub-groups with baseline HBsAg of 101-1000 IU/mL (n=18) and >1000 IU/mL (n=23),the patient sub-group with baseline HBsAg ≤100 IU/mL (n=7) showed statistically significant reduction in HBsAg (P < 0.001) at the end of 24-week treatment and the end of 24-week follow-up. Other baseline characteristics,such as prior interferon treatment and length of prior Nucleot(s)ide analogues (NAs) treatment,had no impact on reduction in HBsAg.

ASC22 was safe and well tolerated in CHB patients. Most adverse events (AEs) (97.5%) were Grade 1-2 in severity. There was no study drug-related serious adverse event (SAE) in 1.0 mg/kg ASC22 cohort.

CHB patients with HBsAg ≤100 IU/mL account for 15%-22% of total CHB patients,according to various studies in China and the U.S. [1,2,3]

Professor Guiqiang Wang,Director of Infectious Diseases Department and Liver Disease Center of Peking University First Hospital,presented today the final data of 1.0 mg/kg ASC22 vs placebo cohort at APASL Annual Meeting 2023.

[1] Jiang Haiyang,Gu Shengwang,Liu Huan,et al.Thoughts on significantly improving clinical cure based on the results of long-term follow-up of 1783 patients with chronic hepatitis B (in Chinese) [J] Chinese Hepatology,2020,25 (2): 4.

[2] O'NeilCR,ConglySE,RoseMS,etal.Long-TermFollow up and Quantitative Hepatitis B Surface Antigen Monitoring in North American Chronic HBV Carriers. Ann Hepatol. 2018;17(2):232-241.

[3] Xie Y,Li M,Ou X,et al. HBeAg-positive patients with HBsAg < 100IU/mL and negative HBV RNA have lower risk of virological relapse after nucleos(t)ide analogues cessation.J Gastroenterol. 2021;56(9):856-867.

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.