Antengene Enters into a Global Clinical Collaboration with MSD to Evaluate ATG-022 (CLDN18.2 ADC) In Combination with KEYTRUDA® (pembrolizumab)

On May 20, 2025 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 medicines for cancer, reported it has entered into a global clinical collaboration with MSD (Merck & Co., Inc., Rahway, NJ, USA) to evaluate the combination of ATG-022, a CLDN18.2-targeting antibody-drug conjugate (ADC), and MSD’s anti-PD-1 therapy, KEYTRUDA (pembrolizumab) in patients with advanced solid tumors (Press release, Antengene, MAY 20, 2025, View Source [SID1234653257]).

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At the 2025 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Gastrointestinal Cancers Symposium (ASCO GI 2025), Antengene presented the latest data from its Phase I/II CLINCH study. Results showed an objective response rate (ORR) of 42.9% and a disease control rate (DCR) of 95.2% in patients with moderate to high CLDN18.2 expression (IHC 2+ ≥ 20%). Additionally, the study demonstrated an ORR of 30.0% and a DCR of 50.0% in patients with low CLDN18.2 expression (IHC 2+ < 20%). ATG-022 also exhibited a favorable safety profile and extended treatment durations, with no observed cases of ophthalmological or neurological toxicities, nor interstitial lung disease.

ATG-022 is uniquely positioned in the global landscape, with data supporting meaningful efficacy across all levels of Claudin 18.2 expression in gastric cancer, including high, low, and ultra-low expressors. This broad-spectrum activity positions ATG-022 as a promising treatment for a wider patient population compared to other CLDN18.2-targeting therapies.

KEYTRUDA is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

About ATG-022

ATG-022 is an antibody-drug conjugate (ADC) designed to target CLDN18.2, a member of the Claudin family of cell adhesion molecules. Under normal conditions, Claudins are located within tight junctions between cells, forming a barrier to regulate cell permeability. However, in cancer, Claudins are aberrantly expressed on the cell surface due to changes in cell polarity. CLDN18.2 is frequently overexpressed in a range of primary malignant tumors, including gastric, esophageal, cholangiocarcinoma, and pancreatic cancers. The U.S. Food and Drug Administration (FDA) has awarded Orphan Drug Designations to ATG-022, for gastric and pancreatic cancers.

Data from the ongoing CLINCH study demonstrated that ATG-022 delivers robust efficacy across all levels of CLDN18.2 expression in gastric cancer patients, including those with high, low, and ultra-low expression. This broad activity positions ATG-022 as a potential market leader, capable of addressing the largest patient population with CLDN18.2-positive tumors. Furthermore, the strong efficacy observed in patients with low CLDN18.2 expression suggests promise for treating other tumor types with similar expression profiles.