Abstract 2575: GD2 targeted dual-labeled intraoperative molecular imaging probe for neuroblastoma
Authors: Sever ReidAnn E. , Rosenblum Lauren Taylor , Stanley Kayla C. , Menendez Dominic M. , Edwards W Barry , Malek Marcus M. , Kohanbash Gary 
Published: March 2024

Abstract
Neuroblastoma (NB) is the most common pediatric extracranial solid tumor, with a 5-year survival rate under 50% for those with high-risk disease. Complete surgical resection is essential for these patients and is associated with improved outcomes. However, NB resection presents significant technical challenges due to encasement of vital structures that must be preserved, as well as remote deposits of disease. The current approach to find and safely resect tumor depends on the surgeon’s eyes and hands alone. Fluorescence tracers allow enhanced tumor visualization, but most are not molecularly targeted which leads to poor tumor to background signal. Further, fluorescent signal does not penetrate more than a few millimeters, a limitation that can be overcome by inclusion of a radiotracer. We, therefore, generated and evaluated a dual radio and fluorescent antibody-based probe targeting the GD2 tumor antigen to improve the identification of NB with widely available intraoperative handheld instruments. We generated an intraoperative probe (111In-αGD2-IRDye800CW) with retained affinity and stability. In vivo- Nu/j mice were injected with SK-N-BE(2) NB cells. After tumors grew for five weeks, mice were given tail vein injections of the probe. Gamma and optical biodistribution studies were performed to determine the specificity of binding and tumor to background signal four- and six-days post probe injection. Probe uptake was compared to an isotype. Gross dissections and surgeries aimed at improving completeness of resection were performed using a handheld fluorescent camera (SPY-PHI) and a gamma probe (Neoprobe). The handheld gamma probe detected xenografts with great sensitivity (average in vivo 818 cps of In111 in tumor region versus 34.8 cps in the tail). The fluorescent imaging showed high specific binding to the tumor region. Gamma biodistribution results indicated high accumulation within tumor (13.5 %ID/g) with lower accumulation in blood (3.49 %ID/g) and muscle (0.45 %ID/g). Uptake of the probe greatly exceeded isotype control antibody on days 4 and 6 post-agent injection, for both gamma and optical biodistributions. Initial tumor resection using 111In-DTPA-aGD2-IRDye800CW in an NB bearing mouse identified residual disease left behind when resection was performed using white light alone; the residual disease was then removed, guided by fluorescence imaging. Our dual-labeled probe demonstrated antigen specificity and allowed for the sensitive detection and visualization of NB in vivo with widely available intraoperative tools. This targeted probe could provide a means to improve surgical NB resection, by enabling localization of the all regions of tumor using radio-guidance, followed by clear definition of tumor margins with fluorescent signal, to maximize preservation of vital tissues. Ultimately, we believe this approach can improve safety, extent of NB resection, and patient outcomes.
Citation Format: ReidAnn E. Sever, Lauren Taylor Rosenblum, Kayla C. Stanley, Dominic M. Menendez, W Barry Edwards, Marcus M. Malek, Gary Kohanbash. GD2 targeted dual-labeled intraoperative molecular imaging probe for neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2575.