Abstract

Background

CD3 bispecific antibodies are a very potent means to re-activate the immune system against tumour cells targeting cancer-associated antigens and CD3 on T cells and acting as direct immune activators. The aim of this study was to investigate the early changes occurring in the tumour and peripheral blood in tumour bearing mice treated with a T cell Bispecific (TCB) antibody designed to elicit T cell activation upon simultaneously binding to T cells and to a tumour-specific target.

Methods

C57Bl/6 mice bearing a B16 metastatic lung murine melanoma were treated with a single dose iv of a TCB targeting murine CD3 and an antigen highly expressed in the B16 tumour. At 2h, 4h, 7h, 24h, 48h after treatment blood was collected for hematology, serum chemistry, cytokines, flow cytometry and pharmacokinetic analysis and the tumour-bearing lung was collected and analyzed for cytokines, flow cytometry and histopathology.

Results

Treatment with the targeted TCB induced, starting from two hours post single dose administration, a transient marked drop in lymphocytes, an increase in neutrophils and monocytes and an increase in acute phase proteins (haptoglobin, SAA1, a1-AGP and SAP) in the peripheral blood, correlating with the histopathological changes at the tumour site. Histopathology, immunohistochemistry and flow cytometry of the tumour showed that acute inflammation was already present at two to four hours after treatment in the form of neutrophilic infiltrate, while CD3⁺ T lymphocytes started to accumulate in the tumour 24h after treatment. These changes were accompanied by an increase of some cytokines in the tumour (e.g. IL-6, MCP1, IL-1b) and in the peripheral blood.

Conclusion

Changes observed in tumour bearing mice upon treatment with a tumour-targeted TCB suggest an early engagement of tumour resident T cells resulting in cytokine release locally and systemically within 2h after treatment, with homing and extravasation of inflammatory cells into the tumour progressively increasing 24h to 48h after treatment. This course of events is believed to be translatable to patients treated with TCBs.

Legal entity responsible for the study

Roche Glycart AG.

Funding

Roche Glycart AG.

Disclosure

A.M. Giusti: Full / Part-time employment: Roche Glycart AG. J. Sam: Full / Part-time employment: Roche Glycart AG. M. Karagianni: Full / Part-time employment: Roche Glycart AG. A. Schneider: Full / Part-time employment: Roche Glycart AG.

中文翻译：

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166P洞悉荷瘤小鼠中T细胞双特异性抗体的作用方式

抽象的

背景

CD3双特异性抗体是一种非常有效的手段，可以重新激活针对肿瘤细胞的免疫系统，该肿瘤细胞靶向与癌症相关的抗原，并在T细胞上具有CD3并起直接免疫激活剂的作用。这项研究的目的是研究用T细胞双特异性（TCB）抗体治疗的荷瘤小鼠在肿瘤和外周血中发生的早期变化，该抗体旨在在与T细胞和肿瘤特异性结合的同时引发T细胞活化目标。

方法

用单剂量iv的靶向鼠CD3的TCB和在B16肿瘤中高表达的抗原治疗携带B16转移性肺鼠黑色素瘤的C57Bl / 6小鼠。在治疗后2小时，4小时，7小时，24小时，48小时，收集血液用于血液学，血清化学，细胞因子，流式细胞术和药代动力学分析，并收集荷瘤肺并分析细胞因子，流式细胞术和组织病理学。

结果

从单剂给药后两个小时开始，用靶向的TCB进行治疗可导致外周血淋巴细胞短暂显着下降，嗜中性粒细胞和单核细胞增多以及外周中急性期蛋白（触珠蛋白，SAA1，a1-AGP和SAP）增加血液，与肿瘤部位的组织病理学变化相关。肿瘤的组织病理学，免疫组织化学和流式细胞术表明，治疗后2-4小时，急性炎症已经以嗜中性粒细胞浸润的形式存在，而治疗后24小时CD3 ⁺ T淋巴细胞开始蓄积在肿瘤中。这些变化伴随着肿瘤和外周血中某些细胞因子（例如IL-6，MCP1，IL-1b）的增加。

结论

在用肿瘤靶向的TCB治疗后在荷瘤小鼠中观察到的变化表明，肿瘤驻留T细胞的早期参与导致细胞因子在治疗后2h内局部和全身释放，炎症细胞的归巢和外渗逐渐增加，从24h到48h治疗后。据认为，这一事件过程可以翻译为接受TCB治疗的患者。

负责研究的法人实体

罗氏Glycart AG。

资金

罗氏Glycart AG。

揭露

AM Giusti：全职/兼职：Roche Glycart AG。J. Sam：全职/兼职：Roche Glycart AG。M. Karagianni：全职/兼职：Roche Glycart AG。A. Schneider：全职/兼职：Roche Glycart AG。