Antennova, a clinical-stage biotech company focused on oncology announced the presentation of latest data from its Phase I/II CLINCH study ongoing in China and Australia evaluating ATN-022 (CLDN18.2 antibody-drug conjugate [ADC]) in patients with advanced or metastatic gastric cancer at the American Society of Clinical Oncology Gastrointestinal Cancers Symposium 2025 (ASCO GI 2025).

• The CLINCH study is a Phase I/II study ongoing in China and Australia with a dose escalation phase followed by a dose expansion phase. As of November 22, 2024, among 21 gastric cancer patients in dose expansion phase with CLDN 18.2 expression of IHC 2+ ≥ 20% who had at least 1 tumor evaluation, the overall response rate (ORR) was 42.9%, and the disease control rate (DCR) was 95.2% (9 partial responses [PRs] including 8 confirmed PRs; and 11 stable diseases [SDs]). 
• Among 10 gastric cancer patients with CLDN 18.2 expression of IHC 2+ < 20% treated at efficacious doses of 1.8 – 2.4 mg/kg, the ORR was 30.0% (1 complete response [CR] and 2 PRs, all PR/CR were confirmed with CLDN 18.2 expression of IHC 2+ < 5%), and the DCR was 50.0%. The patient with CR has demonstrated durable response and has been on the study for over 14 months as of the cut-off date.
• ATN-022 demonstrated a manageable safety profile and promising preliminary antitumor activity in late stage gastric cancer patients across various levels of CLDN18.2 expression, supporting further clinical investigations of ATN-022 in gastric cancer patients. The enrollment of gastric cancer patients for dose optimization and patients with other solid tumors is ongoing in China and Australia.