Antengene Announces First Patient Dosed with Claudin 18.2 Antibody-Drug Conjugate ATG-022 for the Treatment of Patients with Advanced or Metastatic Solid Tumors in Australia

Discovered and developed in-house by Antengene's R&D team, ATG-022 is an antibody-drug-conjugate (ADC) targeting the Tumor Associated Antigen (TAA) Claudin 18.2.

The Phase I CLINCH trial is designed to evaluate the safety,pharmacology,and preliminary efficacy of ATG-022 monotherapy in patients with advanced or metastatic solid tumors. ATG-022 has also received the investigational new drug (IND) approval by the China National Medical Products Administration (NMPA) and is currently recruiting patients with advanced or metastatic solid tumors.

SHANGHAI and HONG KONG,March 29,2023 --Antengene Corporation Limited ("Antengene"SEHK: 6996.HK),a leading innovative,commercial-stage global biopharmaceutical company dedicated to discovering,developing and commercializing first-in-class and/or best-in-class therapeutics in hematology and oncology,today announced that the first patient has been dosed in the Phase I CLINCH trial to evaluate ATG-022 as a monotherapy in patients with advanced or metastatic solid tumors.

The CLINCH trial is a multi-center,open-label Phase I dose-finding study of ATG-022 monotherapy in patients with advanced or metastatic solid tumors.The primary objective of the study is to evaluate the safety and tolerability of ATG-022 and to determine important dosing parameters including maximum tolerated dose (MTD) and recommended Phase II dose (RP2D) of ATG-022 monotherapy. The secondary objective is to characterize the pharmacology and evaluate the preliminary efficacy of ATG-022

"The TAA Claudin 18.2 has become an important cancer target,clinically validated by promising data from different agents and modalities.ATG-022 binds to Claudin 18.2 with low nanomolar affinity and demonstrated potent in vitro andin vivo antitumor effects,including in vivo efficacies demonstrated in Claudin 18.2 low expression models. Having the first patient dosed in the Phase I CLINCH study in Australia marks another milestone in the clinical development program for ATG-022. ATG-022's excellent preclinical activity,safety,coupled with its ADC-based format support our view that ATG-022 has the potential to be an effective treatment and address an unmet need in cancer care." saidDr. Amily Zhang,Antengene's Chief Medical Officer. "We will work closely with all the investigators of this study in efforts to soon provide an effective new treatment option to patients around the world."

About ATG-022

ATG-022 is an antibody-drug-conjugate targeting Claudin 18.2. Claudins are cell adhesion molecules normally expressed within the tight junctions between cells to form a barrier that regulates cell permeability. In cancer,Claudins are expressed at the cell surface due to changes in cell polarity. The Claudin 18.2 isoform is overexpressed in various primary malignant tumors including gastric,esophageal and pancreatic cancers.

Data from preclinical studies,including results from gastric cancer-patient derived xenograft models presented at the 2022 American Association for Cancer Research (2022 AACR),showed that ATG-022 binds to Claudin 18.2 with low nanomolar affinity and demonstrated potent in vitro andin vivoantitumor effects,includingin vivoefficacy demonstrated in Claudin 18.2 low expression models. This could pave the way for broad clinical utility of ATG-022 in gastric cancer patients with a wide range of Claudin 18.2 expression levels. ATG-022 demonstrated an excellent safety profile in Good Laboratory Practice (GLP) toxicology studies.

About Antengene

Antengene Corporation Limited ("Antengene",SEHK: 6996.HK) is a leading commercial-stage R&D-driven global biopharmaceutical company focused on the discovery,development,manufacturing and commercialization of innovative first-in-class/best-in-class therapeutics for the treatment of hematologic malignancies and solid tumors,in realizing its vision of"Treating Patients Beyond Borders".

Since 2017,Antengene has built a pipeline of 9 innovative clinical-stage oncology assets,including 6 with global rights,and 3 with rights for the APAC region. To date,Antengene has obtained 28 investigational new drug (IND) approvals in the U.S. and Asia,and submitted 9 new drug applications (NDAs) in multiple Asia Pacific markets,with the NDA for XPOVIO® (selinexor) already approved in Mainland of China,Taiwan,China,South Korea,Singapore and Australia.

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