Subcutaneously Administered PD-L1 Antibody ASC22 (Envafolimab) is Safe and Well Tolerated in Phase IIa HBV Study

——Phase IIb HBV Clinical Trial Initiated


Hangzhou and Shaoxing, China, Dec 4, 2020 -- Ascletis Pharma Inc. (HKEX:1672) announces today that Phase IIa data demonstrated that ASC22 (Envafolimab) is safe and well tolerated in chronic hepatitis B (CHB) patients and Phase IIb clinical trial has been initiated.  ASC22 (Envafolimab) is a first-in-class, subcutaneously administered PD-L1 antibody. ( Identifier: NCT04465890).


In August this year, the Company started dosing of first HBV patient in Phase IIa single dose escalation clinical trial to explore the safety and tolerability of ASC22 (Envafolimab) in the CHB patients. The data from Phase IIa study indicated that ASC22 (Envafolimab) is safe and well tolerated in the CHB patients receiving nucleos(t)ides as the background therapy. All adverse effects were grade 1 and no grade 2 or above adverse effects were observed to date. Based on such data, the multi-dose phase IIb study initiation meeting of ASC22 (Envafolimab) was held and chaired by Professor Guiqiang Wang, MD, Principal Investigator of the Study and 11th President of Infectious Diseases Society of China, Vice-President of Chinese Society of Physicians for Infectious Diseases and Director of Centre for Liver Diseases at Peking University First Hospital.


“I am impressed with the safety and tolerability data from the Phase IIa study,” said Dr. Guiqiang Wang, “It is exciting that ASC22 (Envafolimab) is entering the Phase IIb study as the first PD-L1/PD-1 antibody for CHB indication. I am looking forward to developing this first-in-class drug candidate with a novel mechanism of action as an immunotherapy, which has the potential to clinically cure CHB and offers convenient subcutaneous injections for patients.”


“We are excited about initiation of this Phase IIb trial in CHB patients,” said Dr. Jinzi J. Wu, Founder, Chairman and CEO of Ascletis. “As a first-in-class immunotherapy to clinically cure CHB, ASC22 (Envafolimab) has potential to be a cornerstone therapy in various treatment regimens, including combinations with our in-house developed drug candidates and potentially with drug candidates from other industrial leaders.”


“Therapeutic activity has been demonstrated for Envafolimab (KN035) in multiple oncology indication along with strong safety profile emerging from more than 1000 patient exposure. Although tremendous progress in HBV treatment has been made recently, we are still in uphill battle to cure this disease,” said Dr. Ting Xu, Chairman of Alphamab. “Because of its superior safety, convenience and compliance, we are confident that KN035, as a first SubQ PD-L1 antibody, will offer a viable option for CHB patients.”


As T cell exhaustion in chronic HBV infections is an important factor in immune tolerance, blocking the PD-1/PD-L1 pathway could be an effective immunotherapy approach to improve specific T cell function and lead to an effective clinical cure for CHB. There are 257 million people worldwide, including 70 million people in China, infected by HBV.



About ASC22

ASC22, also known as KN035 or Envafolimab, exclusively licensed from Alphamab by Ascletis for all viral indications, is a PD-L1 single domain antibody Fc fusion and has the advantages of subcutaneous injection and good stability at room temperature. These would be of great value to improve patients' compliance and quality of life. Ascletis and Suzhou Alphamab Co., Ltd. announced on January 14, 2019 the strategic collaboration and licensing agreement for anti-PD-L1 to treat Hepatitis B and other viral diseases. Envafolimab has been enrolled in more than 1,000 patients and has shown good safety and efficacy in multiple tumor indications. Alphamab has submitted a new drug application for MSI-H solid tumors.


About Alphamab

Suzhou Alphamab Co., Ltd., focused on research and development of mAbs, fusion proteins and other biological macromolecule drugs. With multiple proprietary platforms in antibody screening, protein engineering, CMC development and pilot production set up in its 6000m2 laboratory in bioBAY Suzhou, Alphamab has created a robust pipeline of over 50 programs, of which 20+ are innovative. Alphamab aims to develop affordable and efficient biological drugs to address high unmet medical needs globally.


About Ascletis

Ascletis is an innovative R&D driven biotech and listed on Hong Kong Stock Exchange (1672.HK). Ascletis is committed to developing and commercializing innovative drugs in the areas of viral hepatitis, NASH and HIV/AIDS for unmet medical needs in China and globally. Led by a management team with deep expertise and a proven track record, Ascletis has developed into a fully integrated platform covering the entire value chain from discovery and development to manufacturing and commercialization. Ascletis has three marketed products and thirteen R&D pipeline drug candidates or combination therapies (nine of them developed in-house). 1. Viral hepatitis: (i) Hepatitis B: focus on breakthrough therapies for HBV clinical cure with subcutaneously injected PD-L1 antibody - ASC22 and Pegasys® as cornerstone drugs. (ii) Hepatitis C: successfully launched all oral regimen of Asclevir® and Ganovo® combination (RDV/DNV regimen); and ASC18 fixed dose combination (FDC) is an upgraded version of RDV/DNV regimen with bridging study finished. 2. NASH: Gannex, a wholly-owned company of Ascletis, is fully dedicated to the R&D and commercialization of new drugs in the field of NASH. Gannex has three clinical stage drug candidates against three different targets – FASN, THR-beta and FXR, and three pre-clinical stage combination therapies. 3. HIV/AIDS: ASC09F is a FDC treatment of HIV targeting protease. The clinical trial application of ASC09F has been approved. For more information, please visit


Ascletis Pharma Inc.

Chenlin Li, +86-159-6815-8530


Suzhou Alphamab Co., Ltd. 

Junhong Zhang, +86-512-65951826