Antengene Announces HREC Approval in Australia for the Phase I Trial of the Small Molecule ATR Inhibitor ATG-018

– Discovered in-house bythe internal R&D Team atAntengene,ATG-018 is an orally-bioavailable,small molecule ataxia telangiectasia and Rad3-associated (ATR) kinase inhibitor that targets the DNA damage response (DDR) pathway.

– This Phase I study will evaluate the safety,pharmacology and preliminary efficacy of ATG-018 in patients withadvanced solid tumors and hematologic malignancies.

– ATG-018 has the potential asthe first orally-available,small molecule ATR kinase inhibitor entering clinical development in Australia.

SHANGHAI and HONG KONG,June 7,2022 --Antengene Corporation Limited ("Antengene"SEHK: 6996.HK),a leading 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 Antengene has received approval by the Bellberry Human Research Ethics Committee (HREC) in Australia to initiate the Phase I Trial of ATG-018 in patients with advanced solid tumors and hematologic malignancies (ATRIUM Trial).

ATG-018 is an orally-available,potent,selective small molecule ATR inhibitor. ATG-018 inhibits the ATR kinase,thus limiting cancer cells' ability to repair damaged DNA,in a mechanism also known as synthetic lethality or the DDR.

The primary objective of the study is to evaluate the safety and tolerability of ATG-018 as a monotherapy,to determine the appropriate dose for Phase II studies and assess preliminary efficacy,if available; the secondary objective is to characterize the pharmacology of ATG-018. The study will be conducted in two parts (dose-escalation and dose-expansion). Icon Brisbane in Australia is the lead site for the study,which will be conducted at five sites across Australia.

"DNA is constantly exposed to damage by sources such as ultraviolet light,toxins,certain chemicals,and natural biochemical processes inside our cells. The DNA damage response (DDR) is able to identify DNA damage and to induce various biological processes that correct these changes." Said Dr Jim Coward,Chair of Icon's Medical Oncology Research Committee and Associate Professor at University of Queensland School of Medicine. "The therapeutic landscape of antitumor agents targeting DDR pathways has rapidly expanded to include inhibitors of other key mediators of DNA repair and replication,such as ATR,ATM and DNA-PK[1]. Positive findings from the trials evaluating ATR inhibitors such as ATG-018 may help provide oncologists with a new tool for improving patient outcomes in challenging cases and give them new hope when other therapies have failed."

Dr. Bo Shan,Antengene's Chief Scientific Officercommented,"ATG-018 has a solid preclinical data package including efficacy as a monotherapy in solid tumor models,oral bio-availability and potential predictive biomarkers for response. It is also one of Antengene's first in-house programs to reach the clinic. The differentiated profile of ATG-018 may enable it to be used as monotherapy and open the door for novel collaborations and combination regimens that could benefit cancer patients around the world. We are very pleased to receive HREC approval for the Phase I ATRIUM trial for ATG-018 and we look forward to collaborating with Dr. Coward and the team at Icon Brisbane on this exciting trial."

About the ATRIUM Trial

The ATRIUM trial is a Phase I multi-center,open-label,dose finding study of ATG-018 monotherapy in patients with advanced solid tumors or hematologic malignancies. The primary objective of the study is to evaluate the safety and tolerability of ATG-018 and to determine the maximum tolerated dose (MTD) and/or recommended Phase 2 dose (RP2D) and/or biologically effective dose of ATG-018 monotherapy and preliminary efficacy,if available. The secondary objective is to characterize the pharmacology of ATG-018. As a Phase I study,there will be intensive safety monitoring throughout the trial.

About ATG-018

Discovered by the internal R&D Team at Antengene,ATG-018 is an oral,selective small molecule inhibitor targeting ataxia telangiectasia and Rad3-associated (ATR) kinase. ATR kinase belongs to the phosphoinositide 3 kinase-related family. Inhibiting ATR kinase leads to increased accumulation of single-strand DNA breaks,particularly meaningful for tumor cells which rely on DNA damage repair (DDR). Preclinical studies have demonstrated that ATR inhibitor monotherapy or combination with other drugs (including DDR agents) could be promising therapeutic strategies for solid tumors (including gastric,esophageal,squamous cell carcinoma) and hematologic malignancies (chronic lymphocytic leukemia [CLL],diffuse large B-cell lymphoma [DLBCL] and multiple myeloma [MM]).

According to a preclinical poster presented at 2022 American Association for Cancer Research (AACR 2022) Annual Meeting,ATG-018 has demonstrated potentin vitroandin vivomonotherapy efficacy in solid tumor/hematologic cancer models with certain homologous recombination deficiencies. These data were supported by a series of genetic alterations that correlated with ATG-018 sensitivity and could be potential predictive biomarkers. Taken together,these data suggest that ATG-018 could be a promising therapeutic agent for patients with such homologous recombination deficiencies/genetic alterations.

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 a built broad and expanding pipeline of 15 clinical and preclinical assets,of which 10 are global rights assets,and 5 came with rights for Asia Pacific markets including the Greater China region. To date,Antengene has obtained 24 investigational new drug (IND) approvals in the U.S. and Asia,and submitted 6 new drug applications (NDAs) in multiple Asia Pacific markets,with the NDA for XPOVIO® (selinexor) already approved in mainland China,South Korea,Singapore and Australia.

Forward-looking statements

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References:

[1] Menolfi,D.,Zha,S. ATM,ATR and DNA-PKcs kinases—the lessons from the mouse models: inhibition ≠ deletion. Cell Biosci 10,8 (2020).

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