Kaur Manpreet, Rüger Katja, Chen Elaine C, Rangaswamy Udaya S, Davison Laura M, Moreno Arteaga Sebastian, Smith Imani, Chu Ruth, Chattopadhyay Soumili, Rickert Mathias, Force Aldred Shelley, Harris Katherine E, Trinklein Nathan D, Clarke Starlynn C
Preclinical Biology, Rondo Therapeutics Inc, Hayward, California, USA.
Protein Science, Rondo Therapeutics Inc, Hayward, California, USA.
J Immunother Cancer. 2025 Apr 5;13(4):e011323. doi: 10.1136/jitc-2024-011323.
T-cell costimulation is crucial for an effective and sustained antitumor immune response, and inadequate expression of costimulatory ligands within tumors can impair T-cell function. Bispecific antibodies (bsAbs) targeting a tumor-associated antigen and the T-cell costimulatory receptor CD28 represent a novel class of immune-stimulatory therapeutics designed to enhance antitumor immune responses by selectively delivering T-cell costimulation directly to the tumor microenvironment. This approach holds the potential to improve the survival, proliferation, and cytotoxic function of antitumor T cells while minimizing the risk of systemic immune activation. Urothelial cancer (UC) is associated with significant morbidity and mortality worldwide, particularly in advanced disease settings. Nectin-4, a membrane protein highly expressed in UC with limited expression in healthy tissues, presents a compelling target for therapeutic intervention.
Using our proprietary high-throughput antibody discovery pipeline, we identified a panel of novel antibodies with a range of affinities for CD28 and Nectin-4 and successfully engineered them as bsAbs. We tested the T-cell costimulatory function of these molecules using primary human T cells and human cancer cell lines. Based on these results, we selected a clinical candidate which we assessed in a syngeneic mouse tumor model system and investigated tolerability and pharmacokinetics (PK) in non-human primates (NHP).
Our studies demonstrated that these bsAbs effectively enhance T-cell activation and cytotoxicity against Nectin-4 positive tumor cells in the presence of T-cell receptor engagement. The bsAb panel exhibited a range of potencies, enabling the selection of a clinical candidate, termed RNDO-564, that maximized antitumor efficacy as well as the likelihood of a broad therapeutic window. Tumor-bearing syngeneic mouse models confirmed the efficacy of RNDO-564, demonstrating significant tumor regression both as a single agent and in combination with an immune checkpoint inhibitor. We observed favorable PK and tolerability profiles in NHP assessments.
Our study reports the first CD28 bsAb targeting Nectin-4 and highlights the potential of CD28 × Nectin-4 bsAbs as a new immunotherapeutic modality. The findings support the clinical development of RNDO-564 in patients with locally advanced and metastatic UC and other Nectin-4 positive malignancies.
T细胞共刺激对于有效的持续抗肿瘤免疫反应至关重要，肿瘤内共刺激配体表达不足会损害T细胞功能。靶向肿瘤相关抗原和T细胞共刺激受体CD28的双特异性抗体（bsAbs）代表了一类新型免疫刺激疗法，旨在通过将T细胞共刺激直接选择性地传递到肿瘤微环境来增强抗肿瘤免疫反应。这种方法有可能改善抗肿瘤T细胞的存活、增殖和细胞毒性功能，同时将全身免疫激活的风险降至最低。尿路上皮癌（UC）在全球范围内与显著的发病率和死亡率相关，尤其是在晚期疾病情况下。Nectin-4是一种在UC中高度表达而在健康组织中表达有限的膜蛋白，是治疗干预的一个极具吸引力的靶点。
使用我们专有的高通量抗体发现流程，我们鉴定了一组对CD28和Nectin-4具有一系列亲和力的新型抗体，并成功地将它们工程化为双特异性抗体。我们使用原代人T细胞和人癌细胞系测试了这些分子的T细胞共刺激功能。基于这些结果，我们选择了一个临床候选药物，并在同基因小鼠肿瘤模型系统中对其进行评估，并在非人类灵长类动物（NHP）中研究了耐受性和药代动力学（PK）。
我们的研究表明，这些双特异性抗体在T细胞受体参与的情况下有效地增强了T细胞对Nectin-4阳性肿瘤细胞的激活和细胞毒性。双特异性抗体组表现出一系列效力，从而能够选择一种称为RNDO-564的临床候选药物，其最大限度地提高了抗肿瘤疗效以及具有广泛治疗窗的可能性。荷瘤同基因小鼠模型证实了RNDO-564的疗效，显示其作为单一药物以及与免疫检查点抑制剂联合使用时均有显著的肿瘤消退。我们在非人类灵长类动物评估中观察到了良好的药代动力学和耐受性特征。
我们的研究报告了首个靶向Nectin-4的CD28双特异性抗体，并强调了CD28×Nectin-4双特异性抗体作为一种新的免疫治疗方式的潜力。这些发现支持了RNDO-564在局部晚期和转移性UC患者以及其他Nectin-4阳性恶性肿瘤患者中的临床开发。
