On October 25, 2026 Antengene Corporation Limited ("Antengene", SEHK: 6996.HK), a leading innovative, commercial-stage global biotech company dedicated to discovering, developing and commercializing first-in-class and/or best-in-class medicines for autoimmune diseases, solid tumors and hematological malignancies, reported that it has presented the latest clinical results from the Phase II study of Claudin 18.2 antibody-drug conjugate (ADC) ATG-022 and the Ib/II study of oral CD73 small-molecule inhibitor ATG-037 in poster presentations at the 2026 European Society for Medical Oncology Annual Congress (ESMO 2026).
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Details of the Poster Presentations
ATG-022 (Claudin 18.2 Antibody-Drug Conjugate)
Title: ATG-022, a Claudin 18.2 ADC, in Advanced Gastric and Gastroesophageal Junction Cancer (CLINCH): Phase 2 Results
Poster Number: 2886P
Date: October 25, 2026
Time: 12:00PM-12:45PM (Central European Time)
7:00PM-7:45PM (Beijing Time)
Study Overview:
ATG-022 is a CLDN18.2-targeting ADC comprising a humanized antibody (sub-nM affinity) linked to vc-MMAE. The CLINCH study is a Phase Ⅰ/Ⅱ clinical trial conducted in patients with advanced gastric or gastroesophageal junction adenocarcinoma (GC/GEJC), designed to evaluate the safety, tolerability and preliminary efficacy of ATG-022 monotherapy. The study included a dose escalation phase and a dose expansion/optimization phase. In the dose escalation phase, patients with advanced solid tumors were enrolled regardless of CLDN18.2 expression and received ATG-022 once every three weeks at doses of 0.3–3.0 mg/kg (Q3W). In the Phase Ⅱ dose expansion, CLDN18.2-positive (IHC 1+, ≥1%) patients were enrolled to receive ATG-022 monotherapy at 1.8 mg/kg or 2.4 mg/kg. The efficacy endpoints included objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), evaluated per RECIST 1.1 criteria, and overall survival (OS).
Results:
As of October 12, 2026, a total of 82 patients with GC/GEJC from Australia and China received treatment in the Phase Ⅱ dose expansion phase. This poster highlights data from the 1.8 mg/kg cohort: among the 31 patients, 30 were efficacy evaluable, with an ORR of 46.7%, a DCR of 86.7%, and a mPFS of 5.6 months. Notably, the mOS for the 1.8 mg/kg cohort had not yet been reached after a median follow‑up of 17.4 months, and the 18-month OS rate of intention to treat （ITT）population was 54.8%.
In terms of safety, the incidence of Grade ≥3 TRAEs in the 1.8 mg/kg cohort was 25.8%, the incidence of serious TRAEs was 12.9%, and 12.9% of patients experienced dose interruption due to TRAEs. No individual Grade ≥3 TRAE exceeded 10% incidence in the 1.8 mg/kg cohort.
Conclusion:
These findings demonstrate that ATG-022 monotherapy delivers differentiated efficacy and a favorable safety profile in patients with GC/GEJC. Together with its prior Breakthrough Therapy Designation, these results lay an important foundation for the rapid advancement of CLINCH-3, the pivotal Phase III study of ATG-022. The study has received IND approval from the National Medical Products Administration (NMPA) of China, and the 1.8 mg/kg dose has been recommended for the trial.
In addition, the Company is concurrently conducting the CLINCH-2 study, which evaluates ATG-022 in combination with standard-of-care chemotherapy and an anti-PD-1 antibody for 1L treatment, targeting the broadest CLDN18.2-positive population starting from IHC 1+ ≥1%. Additional data will be presented at future international scientific congresses.
ATG-037 (Oral CD73 Small Molecule Inhibitor)
Title: Efficacy and safety of ATG-037, an oral CD73 inhibitor, plus pembrolizumab in patients with checkpoint inhibitor (CPI) resistant melanoma: Updated results from the STAMINA-01 trial
Poster Number: 2087P
Date: October 24, 2026
Time: 12:00PM-12:45PM (Central European Time)
6:00PM-6:45PM (Beijing Time)
Study Overview:
The immunosuppressive adenosine pathway plays a key role in mediating resistance to PD-(L)1 therapies across tumor types. Preclinical studies have demonstrated synergy when combining CD73 or A2AR blockade with PD-1 or CTLA-4 inhibition. ATG-037 is an oral small-molecule CD73 inhibitor developed by Antengene, designed to achieve complete enzyme inhibition without the "hook effect".
This poster reports updated efficacy and safety data from CPI-resistant melanoma patients receiving ATG-037 in combination with pembrolizumab. As of 28 April 2026, 25 patients with CPI-resistant melanoma received ATG-037 (60–600mg BID) in combination with pembrolizumab (200mg Q3W). Efficacy was assessed via RECIST v1.1. CD73 expression was evaluated by immunohistochemistry (IHC) on tumor or immune cells.
Results:
Among 23 evaluable patients, ATG-037 in combination with pembrolizumab demonstrated an ORR of 21.7% (1 CR, 4 PR) and a DCR of 95.6%. Clinical activity was enriched in patients with high CD73 expression (IHC ≥50% on tumor or immune cells), achieving an ORR of 33.3% (4/12).
The median PFS was 4.4 months (95% CI: 3.7–11.9), and median DOR was not reached. Notably, one patient with cutaneous melanoma achieved an ongoing CR exceeding 167 weeks.
TEAEs and TRAEs occurred in 88% and 52% of patients, respectively. Grade ≥3 TRAEs were limited to a single patient (4%) who experienced Grade 3 diarrhea. The most common TRAEs of any grade included diarrhea (24%), rash (20%), and pruritus (16%).
Conclusion:
ATG-037 in combination with pembrolizumab demonstrates robust, durable efficacy and a favorable safety profile in heavily pretreated, CPI-resistant melanoma. CD73-enriched responses validate the mechanism, supporting further evaluation in CPI-resistant populations.
(Press release, Antengene, OCT 25, 2026, View Source [SID1234673832])