#China #Shanghai #Antengene #ATG-022 #CLDN18.2

Antengene Unveils Promising ATG-022 Clinical Data at ESMO 2025

Antengene Corporation Limited has recently presented crucial data from its ongoing Phase I/II CLINCH study on ATG-022, a promising antibody-drug conjugate targeting CLDN18.2. This presentation took place at the ESMO 2025 Congress. The results demonstrate significant efficacy across varying levels of CLDN18.2 expression and exhibit an exceptional safety profile.

Overview of ATG-022 and Study Design

ATG-022 is designed for targeting CLDN18.2-related cancers and achieved commendable potency thanks to its sub-nM affinity and rapid internalization characteristics. This study is structured into two main phases: dose escalation and dose expansion. During the dose escalation, patients with advanced solid tumors have received ATG-022 across a range of doses (0.3 to 3.0 mg/kg every three weeks), without restrictions based on their CLDN18.2 expression status. In the dose expansion phase, emphasis is placed on patients positive for CLDN18.2, specifically at doses of 1.8 and 2.4 mg/kg.

Efficacy Results

Presented data from the dose expansion phase demonstrates strong efficacy among patients exhibiting moderate to high CLDN18.2 expression (IHC 2+ >20%). Notably, at the 2.4 mg/kg dose, an overall response rate (ORR) of 40% was recorded, showcasing 1 complete response (CR) and 11 partial responses (PR). This cohort's disease control rate (DCR) reached an impressive 90%, with a median progression-free survival (PFS) time of 6.97 months and a 12-month overall survival (OS) rate of 66.2%.

Conversely, the cohort with low or ultra-low CLDN18.2 expression (IHC 2+ ≤20%) indicated promising outcomes as well, with a CR and 5 PRs achieved in 18 patients, leading to an ORR of 33.3% and a DCR of 50%. Impressively, one CR patient remains on the study after more than 22 months, showcasing a durable response potential.

Safety Profile

Regarding safety outcomes, the dose expansion phase revealed that 45.8% of patients experienced at least one treatment-emergent adverse event (TEAE) at the 2.4 mg/kg level, with 60.4% classified as Grade ≥3 TEAEs. However, the 1.8 mg/kg cohort exhibited more favorable safety outcomes, with only 13.6% reporting serious TEAEs and 18.2% experiencing Grade ≥3 TEAEs. These findings highlight the manageable safety profile of ATG-022, supporting its potential application in first-line combination treatments with chemotherapy and immune checkpoint inhibitors.

Conclusion and Future Directions

In conclusion, the preliminary results from the CLINCH study affirm ATG-022's encouraging antitumor effects across a diverse range of CLDN18.2 expressions while maintaining acceptable safety standards. The next steps include deeper exploration of its efficacy in different cancer types, particularly those outside gastrointestinal malignancies, with findings anticipated for presentation at future oncological conferences. This robust dataset positions ATG-022 as a candidate for combination therapies in frontline treatments, thus paving the way for its expanded clinical application and potential market success.