Antengene (6996) Study Update summary

Breakthrough therapy designation and regulatory status

• ATG-022 received Breakthrough Therapy Designation in China for gastric and gastroesophageal junction adenocarcinoma, meeting regulatory criteria for inclusion in the breakthrough therapy drug procedure.

• The designation highlights the potential of ATG-022 for patients with significant unmet medical needs in advanced gastric and gastroesophageal cancers.

• Approval was based on compliance with national drug registration and review procedures.

• ATG-022 is indicated for CLDN18.2-positive, HER2-negative unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma after at least two prior therapies.

Clinical trial design and patient population

• The ongoing Phase I/II CLINCH trial includes subjects with solid tumors, regardless of Claudin 18.2 expression or histology.

• Phase II dose expansion is underway in Australia and China, enrolling multiple tumor types without pre-screening for Claudin 18.2 levels.

• Approximately 120 subjects are planned, focusing on safety, tolerability, and preliminary efficacy.

Efficacy results

• In moderate to high Claudin 18.2 expressors (IHC 2+ >20%), ORR was 40% and DCR 90% at 2.4 mg/kg; ORR was 40% and DCR 84% at 1.8 mg/kg.

• In low and ultra-low expressors (IHC 2+ ≤20%), ORR was 33.3% and DCR 50% at 1.8–2.4 mg/kg.

• Durable responses were observed, with one ultra-low expressor achieving a complete response lasting over 24 months.