SHANGHAI and HONG KONG, China, May 28, 2026
Antengene has announced a major clinical development milestone after receiving endorsement from the Center for Drug Evaluation (CDE) of China’s National Medical Products Administration (NMPA) to initiate the pivotal Phase III CLINCH-3 study of ATG-022, its investigational Claudin 18.2 (CLDN18.2) antibody-drug conjugate (ADC), in patients with CLDN18.2-positive advanced gastric or gastroesophageal junction (GEJ) adenocarcinoma. The endorsement represents a significant advancement for Antengene’s oncology pipeline and supports the transition of ATG-022 into registrational-stage development. The global biotech company plans to launch the study initially in China before expanding into a broader multi-regional clinical trial program, positioning the candidate as a potential next-generation treatment for one of the world’s most challenging gastrointestinal cancers.
Pivotal Phase III CLINCH-3 Trial Targets Unmet Need in Advanced Gastric Cancer
Advanced gastric and gastroesophageal junction adenocarcinomas continue to represent a major global healthcare burden, particularly in Asia where incidence rates remain among the highest worldwide. Despite advances in chemotherapy, immunotherapy, and targeted treatment strategies, patients who progress following standard therapies often face limited options and poor long-term survival outcomes.
The Phase III CLINCH-3 study is designed as a randomized, controlled, open-label, multicenter clinical trial comparing ATG-022 monotherapy against physician-selected standard treatment options. Led by Professor Lin Shen of Peking University Cancer Hospital, the study will evaluate the efficacy and safety of the investigational ADC in patients whose tumors express CLDN18.2, a validated biomarker increasingly recognized as an important therapeutic target in gastric cancer.
The trial’s primary endpoints include progression-free survival (PFS) and overall survival (OS), while secondary endpoints will assess objective response rate, duration of response, disease control rate, and overall safety. As a registrational study, successful results could support future regulatory submissions and potential commercialization of ATG-022 for patients with advanced gastric and gastroesophageal junction cancers.
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Encouraging Early Clinical Data Support Registrational Development
The decision to advance ATG-022 into pivotal development follows promising findings from the ongoing Phase I/II CLINCH study, which demonstrated encouraging anti-tumor activity and a favorable safety profile in heavily pretreated patients. Clinical data generated through December 2025 showed that among patients with CLDN18.2-positive tumors, ATG-022 achieved objective response rates of up to 46.7%, accompanied by disease control rates approaching 90%.
The investigational ADC also demonstrated encouraging progression-free survival outcomes and prolonged overall survival trends, reinforcing confidence in its therapeutic potential. Importantly, the safety profile appeared highly differentiated compared with many currently available ADC therapies. At the selected clinical dose, the incidence of severe treatment-related adverse events remained relatively low, highlighting the potential for effective disease control while maintaining manageable tolerability.
These findings have contributed to growing enthusiasm among investigators and regulatory authorities regarding the candidate’s ability to address a significant unmet need in gastric cancer treatment. The therapy previously received Breakthrough Therapy Designation from China’s CDE, facilitating regulatory interactions and accelerating development discussions leading to the Phase III endorsement.
Expanding Opportunities for CLDN18.2-Targeted Oncology Therapies
ATG-022 belongs to a rapidly emerging class of CLDN18.2-targeted therapeutics, which are gaining increasing attention across the global oncology landscape. CLDN18.2 is highly expressed in a substantial proportion of gastric and gastroesophageal junction cancers, making it an attractive target for precision medicine approaches aimed at improving treatment outcomes while minimizing off-target toxicity.
Beyond the pivotal monotherapy study, Antengene is actively evaluating ATG-022 in combination with anti-PD-1 immunotherapy and chemotherapy in first-line gastric cancer settings. The company is also exploring the ADC’s potential across additional CLDN18.2-positive solid tumors, including cancers outside the digestive system where encouraging early efficacy signals have already been observed.
The initiation of CLINCH-3 underscores Antengene’s growing role in the development of innovative oncology medicines and highlights the increasing importance of antibody-drug conjugates in modern cancer treatment. If successful, ATG-022 could emerge as a best-in-class CLDN18.2-targeted ADC, offering a new treatment option for patients with advanced gastric and gastroesophageal junction adenocarcinoma who currently face limited therapeutic alternatives and poor prognoses.
Source: Antengene press release
