背景:Delta样配体3(DLL3)在小细胞肺癌(SCLC)的细胞表面高表达,最致命的恶性肿瘤之一,但在正常组织中最低或最低,使其成为SCLC的有吸引力的目标。然而,尚无DLL3靶向抗体-药物偶联物(ADC)被批准用于SCLC治疗.我们开发了DB-1314,新的抗DLL3ADC,由新型人源化抗DLL3单克隆抗体(DB131401)与八个分子的P1021(拓扑异构酶I抑制剂)缀合组成,并描述了其临床前资料。
方法:通过生物层干涉法测试DB131401和Rovalpituzumab的结合表位。通过表面等离子体共振和酶联免疫吸附测定分别测量DB-1314对DLL3和其他同源蛋白的结合亲和力和特异性。内部化,旁观者效应,和抗体依赖性细胞介导的细胞毒性(ADCC)通过各自的测定进行评估。通过每个细胞结合的抗体测定和免疫组织化学定量DLL3。在SCLC细胞系中评估了体外和体内生长抑制研究,和细胞系/患者来源的异种移植模型。在食蟹猴中测量安全性概况。
结果:DB-1314诱导强效,耐用,以及体外细胞和体内细胞/患者来源的异种移植模型中的剂量依赖性抗肿瘤作用。DB-1314的杀伤活性机械起因于P1021诱导的DNA损伤,由此P1021通过DLL3特异性结合和有效内化在肿瘤细胞内递送和释放。旁观者效应和ADCC也有助于DB-1314的抗肿瘤活性。DB-1314在大鼠和食蟹猴中显示出良好的药代动力学和毒代动力学特征;此外,DB-1314在猴中在高达60mg/kg的剂量下是良好耐受的。
结论:这些结果表明,DB-1314可能是针对DLL3的候选ADC,用于治疗DLL3阳性SCLC,支持临床环境中的进一步评估。
BACKGROUND: Delta-like ligand 3 (DLL3) is highly expressed on the cell surface of small cell lung cancer (SCLC), one of the most lethal malignancies, but minimally or not in normal tissues, making it an attractive target for SCLC. However, none of the DLL3-targeting antibody-drug conjugates (ADCs) have been approved for SCLC therapy yet. We developed DB-1314, the new anti-DLL3 ADC composed of a novel humanized anti-DLL3 monoclonal antibody (DB131401) conjugated with eight molecules of P1021 (topoisomerase I inhibitor), and described its preclinical profiles.
METHODS: The binding epitope for DB131401 and Rovalpituzumab was tested by biolayer interferometry. The binding affinity and specificity of DB-1314 to DLL3 and other homologous proteins were respectively measured by surface plasmon resonance and enzyme-linked immunosorbent assay. Internalization, bystander effects, and antibody-dependent cell-mediated cytotoxicity (ADCC) were assessed by respective assay. DLL3 was quantified by antibodies bound per cell assay and immunohistochemistry. In vitro and in vivo growth inhibition studies were evaluated in SCLC cell lines, and cell line/patient-derived xenograft models. The safety profile was measured in cynomolgus monkeys.
RESULTS: DB-1314 induces potent, durable, and dose-dependent antitumor effects in cells in vitro and in cell/patient-derived xenograft models in vivo. The killing activity of DB-1314 mechanically arises from P1021-induced DNA damage, whereby P1021 is delivered and released within tumor cells through DLL3-specific binding and efficient internalization. Bystander effects and ADCC also contribute to the antitumor activity of DB-1314. DB-1314 displays favorable pharmacokinetic and toxicokinetic profiles in rats and cynomolgus monkeys; besides, DB-1314 is well-tolerated at a dose of up to 60 mg/kg in monkeys.
CONCLUSIONS: These results suggest that DB-1314 may be a candidate ADC targeting DLL3 for the treatment of DLL3-positive SCLC, supporting further evaluation in the clinical setting.