Ascletis Pharma Inc. today announces the completion of 149 patient enrollment and the positive interim results of Phase IIb study on chronic hepatitis B (CHB) patients in China treated with ASC22 (Envafolimab) -- a first-in-class, subcutaneously administered PD-L1 antibody, in combination with nucleos(t)ide analogs (NAs).
The ASC22 Phase IIb study is a randomized, single-blind, placebo-controlled, multi-center clinical trial in China which evaluates the safety and efficacy of treating patients with CHB for 24-week treatment of 1 mg/kg or 2.5 mg/kg ASC22 or matching placebo given once every two weeks (Q2W) in combination with NAs. Patients enrolled in the study were hepatitis B surface antigen (HBsAg) < 10,000 IU/mL, HBV DNA < 20 IU/mL and negative hepatitis B e-antigen (HBeAg). A total of 149 patients with CHB were enrolled. Among them, 75 patients were 2:1 randomized to 1 mg/kg ASC22 Q2W dosed subcutaneously plus NAs and placebo Q2W dosed subcutaneously plus NAs. 74 patients were 2:1 randomized to 2.5 mg/kg ASC22 Q2W dosed subcutaneously plus NAs and placebo Q2W dose subcutaneously plus NAs (ClinicalTrials.gov Identifier: NCT04465890).
As of July 20, 2021, for the 1 mg/kg ASC22 Q2W plus NAs group, 37% of patients completed 24-week treatment per protocol; 35% of patients completed 14 to 22-week treatment and 28% of patients completed 1 to 12-week treatment; for the 2.5 mg/kg ASC22 Q2W plus NAs group, 7% of patients completed 14 to 24-week treatment and 93% of patients completed 1 to 12-week treatment. Based on the safety data available as of July 20, 2021, the interim analysis indicated the 1 mg/kg ASC22 Q2W plus NAs group had a rate of any adverse events of 75% which was comparable to that (73%) of the placebo Q2W plus NAs group. The rate of grade 3 and 4 adverse events (7%) for the 1 mg/kg ASC22 Q2W plus NAs group was also comparable to that (7%) of the placebo Q2W plus NAs group.
Based on the efficacy data available as of July 20, 2021, the interim analysis indicated that HBsAg reduction was observed for 1 mg/kg ASC22 Q2W plus NAs with more HBsAg reduction observed in patients with HBsAg ≤ 500 IU/mL at baseline while no HBsAg reduction was observed for placebo plus NAs.
Based on the pharmacokinetic data of the Phase IIb study in patients with 1 mg/kg or 2.5 mg/kg ASC22 Q2W plus NAs, the minimum concentrations (Cmin) of ASC22 at steady state are predicted to be > 3 μg/mL one month after both 1 and 2.5 mg/kg dosing, indicating > 90% receptor occupancy in CHB patients over one month after dosing. These data suggest that ASC22 has the potential to be given once a month, which will enhance the compliance and convenience of patients with CHB.
"I am delighted by the safety data so far for 1 mg/kg ASC22 Q2W plus NAs, which was comparable to that of placebo Q2W plus NAs," said Guiqiang Wang, MD, Principal Investigator of the Phase IIb Study, Vice-President of Chinese Society of Physicians for Infectious Diseases and Director of Centre for Liver Diseases at Peking University First Hospital, "Once-a-month dosing of PD-L1 antibody ASC22 will dramatically improve compliance and convenience of patients with CHB."
"The positive interim data of ASC22 plus NAs in the phase IIb study suggest that the combination of PD-L1 antibody ASC22 with other therapies will have great potential to offer functional cure for patients with CHB." said Dr. Jinzi J. Wu, Founder, Chairman and CEO of Ascletis.
"With its advantage in safety, convenience, and compliance, KN035 (ASC22) is potentially bringing solutions for chronical virus diseases, including HBV and HIV." said Dr. Ting Xu, Chairman of Alphamab.
On January 12, 2019, Ascletis entered a strategic partnership agreement for PD-L1 antibody ASC22 (KN035) with Suzhou Alphamab Co., Ltd. (Alphamab). Under the terms of the agreement, Ascletis has an exclusive license from Alphamab to develop and commercialize ASC22 (KN035) for all viral diseases including Hepatitis B and HIV in Greater China. For ASC22 (KN035) in viral indications worldwide outside Greater China, Ascletis will be eligible to share certain economics such as upfront, milestone payments and royalties, depending on the development and regulatory status of ASC22 (KN035) inside Greater China.
About ASC22
ASC22, also known as KN035 or Envafolimab, licensed exclusively by Ascletis for all viral indications from...
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