University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.
Vaccine & Immunotherapy Center, Wistar Institute, Philadelphia, Pennsylvania, USA.
J Immunother Cancer. 2024 Jun 4;12(6):e008733. doi: 10.1136/jitc-2023-008733.
Advanced clear cell renal cell carcinoma (ccRCC) is a prevalent kidney cancer for which long-term survival rates are abysmal, though immunotherapies are showing potential. Not yet clinically vetted are bispecific T cell engagers (BTEs) that activate T cell-mediated cancer killing through intercellular synapsing. Multiple BTE formats exist, however, with limited cross-characterizations to help optimize new drug design. Here, we developed BTEs to treat ccRCC by targeting carbonic anhydrase 9 (CA9) while characterizing the persistent BTE (PBTE) format and comparing it to a new format, the persistent multivalent T cell engager (PMTE). These antibody therapies against ccRCC are developed as both recombinant and synthetic DNA (synDNA) medicines.
Antibody formatting effects on binding kinetics were assessed by flow cytometry and intercellular synaptic strength assays while potency was tested using T-cell activation and cytotoxicity assays. Mouse models were used to study antibody plasma and tumor pharmacokinetics, as well as antitumor efficacy as both recombinant and synDNA medicines. Specifically, three models using ccRCC cell line xenografts and human donor T cells in immunodeficient mice were used to support this study.
Compared with a first-generation BTE, we show that the PBTE reduced avidity, intercellular synaptic strength, cytotoxic potency by as much as 33-fold, and ultimately efficacy against ccRCC tumors in vivo. However, compared with the PBTE, we demonstrate that the PMTE improved cell avidity, restored intercellular synapses, augmented cytotoxic potency by 40-fold, improved tumor distribution pharmacokinetics by 2-fold, and recovered synDNA efficacy in mouse tumor models by 20-fold. All the while, the PMTE displayed a desirable half-life of 4 days in mice compared with the conventional BTE's 2 hours.
With impressive efficacy, the CA9-targeted PMTE is a promising new therapy for advanced ccRCC, which can be effectively delivered through synDNA. The highly potent PMTE format itself is a promising new tool for future applications in the multispecific antibody space.
晚期透明细胞肾细胞癌（ccRCC）是一种常见的肾癌，尽管免疫疗法具有潜力，但长期生存率仍很低。尚未经过临床检验的是双特异性 T 细胞衔接器（BTE），它通过细胞间突触激活 T 细胞介导的癌症杀伤。存在多种 BTE 格式，但对它们进行的交叉特征描述有限，无法帮助优化新药设计。在这里，我们通过靶向碳酸酐酶 9（CA9）开发了治疗 ccRCC 的 BTE，并对持续 BTE（PBTE）格式进行了特征描述，并将其与新格式持续多价 T 细胞衔接器（PMTE）进行了比较。这些针对 ccRCC 的抗体疗法被开发为重组和合成 DNA（synDNA）药物。
通过流式细胞术和细胞间突触强度测定评估抗体格式对结合动力学的影响，同时通过 T 细胞激活和细胞毒性测定测试效力。使用小鼠模型研究抗体的血浆和肿瘤药代动力学以及作为重组和 synDNA 药物的抗肿瘤功效。具体来说，使用三种模型，即使用 ccRCC 细胞系异种移植物和免疫缺陷小鼠中的人类供体 T 细胞，支持这项研究。
与第一代 BTE 相比，我们发现 PBTE 降低了亲和力、细胞间突触强度和细胞毒性效力多达 33 倍，最终降低了体内 ccRCC 肿瘤的疗效。然而，与 PBTE 相比，我们证明 PMTE 提高了细胞亲和力、恢复了细胞间突触、将细胞毒性效力提高了 40 倍、改善了肿瘤分布药代动力学、恢复了 synDNA 在小鼠肿瘤模型中的功效提高了 20 倍。同时，与传统的 BTE 的 2 小时半衰期相比，PMTE 在小鼠中的半衰期为 4 天。
具有令人印象深刻的疗效，靶向 CA9 的 PMTE 是一种有前途的晚期 ccRCC 新疗法，可以通过 synDNA 有效递送。高效的 PMTE 格式本身是多特异性抗体领域未来应用的有前途的新工具。
