Improved Discrimination of Tumors with Low and Heterogeneous EGFR Expression in Fluorescence-Guided Surgery Through Paired-Agent Protocols

Abstract

Purpose The goal of fluorescence-guided surgery (FGS) in oncology is to improve the surgical therapeutic index by enhancing contrast between cancerous and healthy tissues. However, optimal discrimination between these tissues is complicated by the nonspecific uptake and retention of molecular targeted agents and the variance of fluorescence signal. Paired-agent imaging (PAI) employs co-administration of an untargeted imaging agent with a molecular targeted agent, providing a normalization factor to minimize nonspecific and varied signals. The resulting measured binding potential is quantitative and equivalent to in vivo immunohistochemistry of the target protein. This study demonstrates that PAI improves the accuracy of tumor-to-healthy tissue discrimination compared to single-agent imaging for in vivo FGS. Procedures PAI using a fluorescent anti-epidermal growth factor receptor (EGFR) affibody molecule (ABY-029, eIND 122,681) with untargeted IRDye 700DX carboxylate was compared to ABY-029 alone in an oral squamous cell carcinoma xenograft mouse model at 3 h after dye administration (n = 30). Results PAI significantly enhanced tumor discrimination, as compared to ABY-029 alone in low EGFR-expressing tumors and highly heterogeneous populations including multiple cell lines with varying expression (diagnostic accuracy: 0.908 vs. 0.854 and 0.908 vs. 0.822; and ROC curve AUC: 0.963 vs. 0.909 and 0.957 vs. 0.909, respectively) indicating a potential for universal FGS image thresholds to determine surgical margins. In addition, PAI achieved significantly higher diagnostic ability than ABY-029 alone 0.25–5-h post injection and exhibited a stronger correlation to EGFR expression heterogeneity. Conclusion The quantitative receptor delineation of PAI promises to improve the surgical therapeutic index of cancer resection in a clinically relevant timeline.

Towards Photodynamic Image-Guided Surgery of Head and Neck Tumors: Photodynamic Priming Improves Delivery and Diagnostic Accuracy of Cetuximab-IRDye800CW

“…FIGURE 7 | The path towards photodynamic image-guided surgery proposed, including anticipated necessary metrics, in accordance with the published path of clinical translation of Cet-IRDye800 and related IGS probes(10,30,(44)(45)(46).…”

“…Point measurements were performed using ImageJ and ROC curves were generated using GraphPad Prism v9.2.0. Contrast-based diagnostic accuracy analyses (contrast-variance) were performed according to the following equation ( 30 ):…”

“…Given these caveats, the power of the PDP approach we present here lies in its ability to increase the accuracy of tumor detection by Cet-IRDye800 with respect to healthy tissue. As such, the widely accepted gold standard used for assessing the potential for improving the accuracy of image-guided surgery in a preclinical and clinical setting is using fluorescence-based imaging of the tissue sections ex vivo followed by receiver operating characteristic curve (ROC) quantitation of specificity and sensitivity (10,30,31,(33)(34)(35)(36). This is demonstrated in Figure 5, where ROC curves represent the sensitivity and specificity of tumor tissue detection by Cet-IRDye800 with and without PDP.…”

“…The evidence presented in this proof-of-concept warrants the pursuit of P-IGS. The pathway to P-IGS will comprise multiple stages of pre-clinical and clinical development, which can be modeled on the paths taken for the clinical translation of molecular probes for IGS (10,11,30,(44)(45)(46). Figure 7 is a multi-stage pathway proposed for the further development of the P-IGS approach, which is modeled on these aforementioned paths used for translating Cet-IRDye800 and related probes.…”

“…The dose-dependent specificity of Cet-IRDye800 with and without the optimized PDP regimen would also need full assessment in human subjects, followed by the assessment of how this P-IGS approach may provide maximal patient tumor resection, reduce local recurrence rates, reduce the time to recurrence and prolong progression-free and overall survival. This P-IGS approach holds considerable potential for maximizing the extent and accuracy of resection within clinically-relevant time frames, while enabling (10,30,(44)(45)(46).…”