#USA #Berlin #Antengene #ATG-022 #CLDN18.2

Antengene's Groundbreaking Presentation at ESMO 2025

On October 19, 2025, Antengene Corporation Limited, a prominent global biotech firm focusing on innovative therapies for cancer, made waves at the European Society for Medical Oncology Congress (ESMO 2025) held in Berlin, Germany. The company presented the latest findings from its ongoing Phase I/II clinical trial, known as the CLINCH study, highlighting the promising results of ATG-022, an antibody-drug conjugate (ADC) aimed at treating advanced gastric and gastroesophageal junction cancer targeting CLDN18.2 expression.

Overview of ATG-022 and the CLINCH Study

ATG-022 operates as a CLDN18.2-targeted ADC established for its potent affinity and rapid internalization properties. By utilizing a unique VC-MMAE linker-payload, the therapy exhibited significant activity across varied levels of CLDN18.2 expression—high, low, and ultra-low. The ongoing CLINCH study was structured into two phases: dose escalation and dose expansion.

Participants in the dose escalation segment were patients suffering from advanced solid tumors, regardless of CLDN18.2 expression levels, who received up to 3.0 mg/kg of ATG-022 once every three weeks to evaluate its safety and pharmacokinetics. Meanwhile, CLDN18.2 positive patients underwent treatment in the dose expansion phase at 1.8 mg/kg or 2.4 mg/kg to study both efficacy and safety.

ATG-022 has garnered Orphan Drug Designations from the U.S. Food and Drug Administration (FDA) for gastric and pancreatic cancer, while also securing Breakthrough Therapy Designation from China's National Medical Products Administration (NMPA) for specific gastric cancer cases resistant to prior treatments.

Key Efficacy Results

The latest data from the study revealed that among patients with moderate to high CLDN18.2 expression, the 2.4 mg/kg dose cohort recorded notable outcomes: one complete response (CR), eleven partial responses (PRs), and fifteen stable diseases (SDs). Consequently, this resulted in an objective response rate (ORR) of 40% and a disease control rate (DCR) of 90%. Additionally, the median progression-free survival (mPFS) was 6.97 months with a 12-month overall survival (OS) rate of 66.2% for those patients. The 1.8 mg/kg cohort also mirrored success with an ORR of 40% and a DCR of 84%.

Interestingly, data showed that CLDN18.2 low and ultra-low expressing patients treated at the effective doses achieved an ORR of 33.3%, with one patient sustaining a CR for over 22 months.

Safety Profile and Observations

In the context of patient safety, the 2.4 mg/kg dose expansion phase observed 45.8% of participants experiencing treatment-emergent adverse events (TEAEs), with 60.4% reporting grade ≥3 TEAEs. The most frequently reported serious adverse events included decreases in neutrophil count and appetite. Remarkably, the safety profile at the 1.8 mg/kg dose level reflected even more favorably, with significantly fewer adverse events.

Notably, no instances of ophthalmological toxicities or interstitial lung disease were documented, which is particularly promising for future applications, especially in combination with immune checkpoint inhibitors and chemotherapy.

Conclusions and Future Directions

The outcomes showcased by ATG-022 allow for compelling prospects as a new treatment avenue for varying CLDN18.2 expressive patient groups. The encouraging safety and efficacy data lay down a robust foundation for advancing clinical trials, with the next phases involving potential combination therapies.

The ongoing clinical study continues to progress smoothly in territories such as China and Australia, as Antengene gears up for deploying combination therapies featuring ATG-022.

About Antengene Corporation

Founded with a vision to develop pioneering therapies for medical conditions with unmet needs, Antengene Corporation operates on a global scale, focusing on innovative oncological treatments, including the likes of ATG-022 and other therapeutics in various stages of clinical development. With numerous IND approvals across the U.S. and Asia, the company aims to broaden its therapeutic frontiers and provide new hope to cancer patients worldwide.