Thayer School of Engineering, Dartmouth College, Hanover, NH, USA.
Geisel School of Medicine, Dartmouth College, Hanover, NH, USA.
Mol Imaging Biol. 2023 Feb;25(1):97-109. doi: 10.1007/s11307-021-01642-9. Epub 2021 Oct 12.
Non-specific uptake and retention of molecular targeted agents and heterogeneous tissue optical properties diminish the ability to differentiate between tumor and normal tissues using molecular targeted fluorescent agents. Paired-agent imaging (PAI) can increase the diagnostic ability to detect tumor tissue by mitigating these non-specific effects and providing true molecular contrast by co-administration of an untargeted control imaging agent with a targeted agent. This study evaluates the suitability of available clinically translatable untargeted agents for the translation of PAI in fluorescence-guided surgery using an affibody-based targeted imaging agent (ABY-029).
DESIGN: Three untargeted agents that fluoresce near 700 nm and exhibit good clinical safety profiles (methylene blue, IRDye 700DX, and IRDye 680LT) were tested in combination with the clinically tested IRDye 800CW-labeled anti-epidermal growth factor receptor (EGFR) affibody molecule, ABY-029 (eIND 122,681). Properties of the untargeted agent important for human use and integrity of PAI were tested: (1) plasma protein binding; (2) fluorescence signal linearity in in vitro whole blood dilution; (3) in vivo pharmacokinetic matching to targeted agent in negative control tissue; and (4) in vivo diagnostic accuracy of PAI vs single agent imaging (SAI) of ABY-029 alone in orthotopic oral head and neck squamous cell carcinomas.
IRDye 680LT outperformed IRDye 700DX and methylene blue with the highest signal linearity (R = 0.9998 ± 0.0002, 0.9995 ± 0.0004, 0.91 ± 0.02, respectively), the highest fluorescence yield in whole blood at 1 μM (10, 10, 10, respectively), and the most closely matched ABY-029 pharmacokinetics in EGFR-negative tissues (binding potential error percentage = 0.31% ± 0.37%, 10.25% ± 1.30%, and 8.10% ± 5.37%, respectively). The diagnostic ability of PAI with ABY-029 and IRDye 680LT outperformed conventional SAI with an area-under-the-receiver-operating-characteristic curve (AUC) value of 0.964 vs. 0.854, and 0.978 vs. 0.925 in the Odyssey scanning system and Pearl wide field imaging system, respectively.
PAI is a highly promising methodology for increasing detection of tumors in fluorescence-guided surgery. Although not yet clinically approved, IRDye 680LT demonstrates promise as an untargeted agent when paired with ABY-029. The clinical translation of PAI to maximize tumor excision, while minimizing normal tissue removal, could improve both patient survival and life quality.
非特异性摄取和保留分子靶向剂以及组织光学性质的不均匀性降低了使用分子靶向荧光剂区分肿瘤组织和正常组织的能力。配对剂成像（PAI）可以通过减轻这些非特异性效应并通过与靶向剂一起施用非靶向对照成像剂来提供真正的分子对比，从而提高检测肿瘤组织的诊断能力。本研究评估了三种现有的临床可转化的非靶向剂在使用基于亲和体的靶向成像剂（ABY-029）的荧光引导手术中进行 PAI 转化的适用性。
设计：三种在近 700nm 处荧光且具有良好临床安全性的非靶向剂（亚甲蓝、IRDye 700DX 和 IRDye 680LT）与临床测试的 IRDye 800CW 标记的抗表皮生长因子受体（EGFR）亲和体分子 ABY-029（eIND 122,681）联合进行了测试。对于人体使用和 PAI 完整性很重要的非靶向剂特性进行了测试：（1）血浆蛋白结合；（2）体外全血稀释中的荧光信号线性；（3）在阴性对照组织中与靶向剂的体内药代动力学匹配；（4）与 ABY-029 单独的单剂成像（SAI）相比，PAI 的体内诊断准确性在原位口腔头颈部鳞状细胞癌中。
IRDye 680LT 在信号线性方面优于 IRDye 700DX 和亚甲蓝，具有最高的信号线性（R=0.9998±0.0002、0.9995±0.0004、0.91±0.02，分别），在 1μM 全血中的最高荧光产率（分别为 10、10、10），以及与 EGFR 阴性组织中 ABY-029 最匹配的药代动力学（结合潜能误差百分比=0.31%±0.37%、10.25%±1.30%和 8.10%±5.37%，分别）。与传统的 SAI 相比，ABY-029 和 IRDye 680LT 的 PAI 诊断能力具有更高的诊断能力，其曲线下面积（AUC）值分别为 0.964 比 0.854 和 0.978 比 0.925，在 Odyssey 扫描系统和 Pearl 宽场成像系统中分别。
PAI 是一种很有前途的荧光引导手术中增加肿瘤检测的方法。虽然尚未获得临床批准，但当与 ABY-029 配对时，IRDye 680LT 作为非靶向剂具有很大的潜力。PAI 的临床转化可以最大限度地切除肿瘤，同时最大限度地减少正常组织的切除，从而提高患者的生存率和生活质量。
