Background. Although therapeutic advances have led to enhanced survival in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer, detection of residual disease remains challenging. Here, we examine two approved anti-HER2 monoclonal antibodies (mAbs), trastuzumab and pertuzumab, as potential candidates for the development of immunoconjugates for fluorescence-guided surgery (FGS). Methods. mAbs were conjugated to the near-infrared fluorescent (NIRF) dye, IRDye800, and for quantitative in vitro assessment, to the radiometal chelator, desferrioxamine, to enable dual labeling with ⁸⁹Zr. In vitro binding was evaluated in HER2-overexpressing (BT474, SKBR3) and HER2-negative (MCF7) cell lines. BT474 and MCF7 xenografts were used for in vivo and ex vivo fluorescence imaging. Results. In vitro findings demonstrated HER2-mediated binding for both fluorescent immunoconjugates and were in agreement with radioligand assays using dual-labeled immunoconjugates. In vivo and ex vivo studies showed preferential accumulation of the fluorescently-labeled mAbs in tumors and similar tumor-to-background ratios. In vivo HER2 specificity was confirmed by immunohistochemical staining of resected tumors and normal tissues. Conclusions. We showed for the first time that fluorescent trastuzumab and pertuzumab immunoconjugates have similar NIRF imaging performance and demonstrated the possibility of performing HER2-targeted FGS with agents that possess distinct epitope specificity.

中文翻译：

---

HER2靶向抗体在乳腺癌荧光引导手术中的比较

背景。尽管治疗进展已导致人类表皮生长因子受体 2 (HER2) 阳性乳腺癌患者的生存率提高，但残留疾病的检测仍然具有挑战性。在这里，我们检查了两种已获批准的抗 HER2 单克隆抗体 (mAb)，曲妥珠单抗和帕妥珠单抗，作为开发用于荧光引导手术 (FGS) 的免疫偶联物的潜在候选者。方法。mAb 与近红外荧光 (NIRF) 染料 IRDye800 偶联，并与放射性金属螯合剂去铁胺偶联进行体外定量评估，以实现⁸⁹ Zr 的双重标记。体外在 HER2 过表达 (BT474, SKBR3) 和 HER2 阴性 (MCF7) 细胞系中评估结合。BT474 和 MCF7 异种移植物用于体内和体外荧光成像。结果。体外研究结果表明 HER2 介导的两种荧光免疫偶联物的结合，并与使用双标记免疫偶联物的放射性配体测定一致。体内和体外研究显示荧光标记的 mAb 在肿瘤中的优先积累和相似的肿瘤与背景比率。通过切除肿瘤和正常组织的免疫组织化学染色证实了体内HER2 特异性。结论. 我们首次展示了荧光曲妥珠单抗和帕妥珠单抗免疫偶联物具有相似的 NIRF 成像性能，并证明了使用具有不同表位特异性的试剂进行 HER2 靶向 FGS 的可能性。