PO.ET02.02 · 实验与分子治疗
用 eKiH 工程化 CLDN18.2×HER2 双特异性 ADC 克服胃癌中的靶点异质性
Overcoming target heterogeneity in gastric cancer with an eKiH-engineered CLDN18.2×HER2 bispecific ADC
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：靶点异质性、CLDN18.2 和 HER2 的镶嵌和簇状表达在胃癌（GC）中很常见，并削弱了单抗原疗法的疗效。我们此前开发了 DA3501（AT-211），一种靶向 CLDN18.2 的 ADC，目前正推进至 1 期评估。DA3501 抗体克隆与 zolbetuximab 相比显示出增强的亲和力和内化。为了更全面地应对异质性肿瘤，我们基于 Dong-A ST BsAb 平台工程化了一种 CLDN18.2×HER2 双特异性 ADC，采用增强型 knob-into-hole（eKiH）界面来提高重链配对保真度和双特异性组装。
方法：抗体发现和优化产生了 CLDN18.2 和 HER2 的先导克隆，具有改善的结合和内化。使用 Dong-A ST BsAb 平台组装双特异性抗体。使用位点选择性化学方法进行与单甲基澳瑞他汀 E（MMAE）、exatecan（一种拓扑异构酶 I 抑制剂）或双载荷配置的偶联。使用肿瘤标本的单细胞 RNA 测序（scRNA-seq）和组织芯片（TMA）上的多重免疫组织化学（mIHC）在人类 GC 中评估靶点流行率和共表达。分析免疫相关性以评估与免疫检查点抑制剂（ICI）联合的潜力。
结果：scRNA-seq 揭示了 CLDN18.2 和 HER2 在相互排斥以及共表达的肿瘤细胞亚群中的表达，mIHC 显示的瘤内镶嵌和簇状模式对此予以佐证。DA3501 抗 CLDN18.2 克隆表现出优于 zolbetuximab 的结合动力学和内化。ATS1002 保留了对两个靶点的高亲和力结合，并在双阳性和单阳性（CLDN18.2 或 HER2）模型中显示出高效内化，支持了针对异质性病灶的“通杀”方法。偶联有 MMAE、exatecan 或双载荷的 ADC 在 CLDN18.2 高、HER2 高和共表达的 GC 细胞系中显示出强效的体外细胞毒性。免疫相关分析表明，在表现出激活的 T 细胞和髓系特征的肿瘤中，其与 ICI 具有潜在协同作用。
结论：这种 BsAb 是一种合理工程化的 CLDN18.2×HER2 双特异性 ADC，旨在克服 GC 中的靶点异质性。与 DA3501 项目一起，它拓宽了对表达 CLDN18.2/HER2 肿瘤的治疗覆盖以及联合策略研究，包括 ICI 联合治疗。
查看英文原文 English abstract
Background: Target heterogeneity, mosaic and cluster expression of CLDN18.2 and HER2 is common in gastric cancer (GC) and undermines the efficacy of single-antigen therapies. We previously developed DA3501 (AT-211), a CLDN18.2-targeting ADC currently advancing toward Phase 1 evaluation. The DA3501 antibody clone demonstrates enhanced affinity and internalization compared with zolbetuximab. To more comprehensively address heterogeneous tumors, we engineered a CLDN18.2×HER2 bispecific ADC built on Dong-A ST BsAb platform incorporating an enhanced knob-into-hole (eKiH) interface to improve heavy-chain pairing fidelity and bispecific assembly.
Methods: Antibody discovery and optimization yielded lead clones for CLDN18.2 and HER2 with improved binding and internalization. Bispecifics were assembled using Dong-A ST BsAb platform. Conjugation to monomethyl auristatin E (MMAE), exatecan (a topoisomerase-I inhibitor), or dual-payload configurations was performed using site-selective chemistry. Target prevalence and co-expression were evaluated in human GC using single-cell RNA sequencing (scRNA-seq) of tumor specimens and multiplex immunohistochemistry (mIHC) on tissue microarrays (TMAs). Immune correlates were analyzed to assess combinatorial potential with immune checkpoint inhibitors (ICIs).
Results: scRNA-seq revealed CLDN18.2 and HER2 expression in mutually exclusive as well as co-expressing tumor cell subsets, corroborated by mIHC showing intra-tumoral mosaic and clustered patterns. The DA3501 anti-CLDN18.2 clone exhibited superior binding kinetics and internalization versus zolbetuximab. ATS1002 retained high-affinity binding to both targets and demonstrated efficient internalization in dual-positive and single-positive (CLDN18.2 or HER2) models, supporting a “catch-all” approach for heterogeneous lesions. ADCs conjugated with MMAE, exatecan, or dual payloads showed potent in vitro cytotoxicity across CLDN18.2-high, HER2-high, and co-expressing GC lines. Immune-correlative analyses indicated potential synergy with ICIs in tumors exhibiting activated T-cell and myeloid signatures.
Conclusions: This BsAb is a rationally engineered CLDN18.2×HER2 bispecific ADC designed to overcome target heterogeneity in GC. Together with the DA3501 program, it broadens therapeutic coverage of CLDN18.2/HER2-expressing tumors and combination-strategy studies, including ICI co-therapy.
利益披露 Disclosure
K. Pyo, None..
S. Park, None..
D. Lee, None..
H. Kim, None..
Y. Kong, None..
Y. Lee, None..
H. Yeom, None..
S. Aum, None..
S. Park, None..
H. Oh, None..
C. Kim, None..
H. Jin, None..
A. Lee, None..
H. Hong, None..
J. Kim, None..
H. Choi, None..
M. Kim, None..
T. Han, None.