Antengene Presents Latest ATG-022 Clinical Data at ESMO 2025 Demonstrating Efficacy Across All CLDN18.2 Expression Levels and Exceptional Tolerability

• ATG-022 is a CLDN18.2-targeted ADC with sub-nM affinity and fast internalization. Using a VC-MMAE linker-payload (DAR 4), ATG-022 has demonstrated potent activity across tumors with high/low/ultra-low CLDN18.2 expression.
• The ongoing Phase I/II CLINCH study consists of dose escalation and dose expansion phases. In dose escalation, patients with advanced solid tumors regardless of CLDN18.2 expression receive ATG-022 (0.3-3.0 mg/kg Q3W) to evaluate safety, tolerability, and pharmacokinetics; CLDN18.2-positive (≥IHC 1+, 1%) patients are treated at 1.8 or 2.4 mg/kg in dose expansion to evaluate the efficacy and safety.

Key Results Presented

• Efficacy:
  • Among GC/GEJC patients with moderate/high CLDN18.2 expression (IHC 2+ >20%), the 2.4 mg/kg dose cohort observed 1 CR, 11 PRs and 15 SDs, resulting in 40% ORR (12/30) and 90% DCR (27/30). The median PFS was 6.97 months and the 12-month OS rate was 66.2%. In the 1.8 mg/kg dose cohort, there were 1 CR, 9 PRs, and 11 SDs, giving a 40% ORR (10/25) and 84% DCR (21/25).
  • Among GC/GEJC patients with low/ultra-low CLDN18.2 expression (IHC 2+ ≤20%), patients treated at the efficacious dose of 1.8-2.4 mg/kg achieved 1 CR and 5 PRs, resulting in 33.3% ORR (6/18) and 50%DCR (9/18). The CR patient has demonstrated durable response and has been on the study for 22+ months.
• Safety:
  • At 2.4 mg/kg in the dose expansion, 45.8% of patients had ≥1 TEAEs, 60.4% of patients had grade ≥3 TEAEs.
  • In the dose-expansion phase, the 1.8 mg/kg cohort demonstrated excellent safety and tolerability, with only 13.6% of patients reporting serious TEAEs and 18.2% reporting Grade ≥3 TEAEs. The favorable safety profile of this dose level support its potential use in first-line combination regimens with chemotherapy and immune checkpoint inhibitors.

Conclusions and Outlook

• ATG-022 demonstrated a manageable safety profile and encouraging antitumor effects in GC/GEJC adenocarcinoma patients with a broad range of CLDN18.2 expressions, thus supporting further clinical investigation in patients with variable CLDN18.2 expressions.
• Preliminary efficacy has also been observed in other non-GI tumor types which will be reported at upcoming conferences.
• The 2.4 mg/kg cohort showed a favorable safety profile, while the 1.8 mg/kg cohort demonstrated even better safety and tolerability. These findings provide strong support for advancing ATG-022 in combination with immune checkpoint inhibitors and chemotherapy in first-line treatment settings, paving the way to significantly expand its clinical reach and commercial potential.

Forward-looking statements
Please refer: https://www.antengene.com/newsinfo/442

For more information, please contact:

Investor Contacts:
Donald Lung
E-mail: donald.lung@antengene.com 

BD Contacts:
Ariel Guo
E-mail: ariel.guo@antengene.com 

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