Intraoperative molecular imaging of colorectal lung metastases with SGM-101:a feasibility study

Purpose: Metastasectomy is a common treatment option for patients with colorectal lung metastases (CLM). Challenges exist with margin assessment and identification of small nodules, especially during minimally invasive surgery. Intraoperative fluorescence imaging has the potential to overcome these challenges. The aim of this study was to assess feasibility of targeting CLM with the carcinoembryonic antigen (CEA) specific fluorescent tracer SGM-101. Methods: This was a prospective, open-label feasibility study. The primary outcome was the number of CLM that showed a true positive fluorescence signal with SGM-101. Fluorescence positive signal was defined as a signal-to-background ratio (SBR) ≥ 1.5. A secondary endpoint was the CEA expression in the colorectal lung metastases, assessed with the immunohistochemistry, and scored by the total immunostaining score. Results: Thirteen patients were included in this study. Positive fluorescence signal with in vivo, back table, and closed-field bread loaf imaging was observed in 31%, 45%, and 94% of the tumors respectively. Median SBRs for the three imaging modalities were 1.00 (IQR: 1.00–1.53), 1.45 (IQR: 1.00–1.89), and 4.81 (IQR: 2.70–7.41). All tumor lesions had a maximum total immunostaining score for CEA expression of 12/12. Conclusion: This study demonstrated the potential of fluorescence imaging of CLM with SGM-101. CEA expression was observed in all tumors, and closed-field imaging showed excellent CEA specific targeting of the tracer to the tumor nodules. The full potential of SGM-101 for in vivo detection of the tracer can be achieved with improved minimal invasive imaging systems and optimal patient selection. Trial registration: The study was registered in ClinicalTrial.gov under identifier NCT04737213 at February 2021.</p

Étude du trafic intracellulaire de protéines membranaires de la famille de la néprilysine

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Les anticorps, outils de choix pour la chirurgie guidée par fluorescence

La chirurgie guidée par fluorescence se développe en clinique depuis plusieurs années. Si l’utilisation de colorants non ciblés peut être utile dans certaines pathologies, des agents de contraste spécifiques sont indispensables en oncologie. Comme le montrent les dernières études cliniques, les anticorps monoclonaux ont toutes les caractéristiques pour jouer un rôle majeur dans ce domaine d’imagerie médicale, à condition que la cible antigénique soit pertinente

SGM-101: An innovative near-infrared dye-antibody conjugate that targets CEA for fluorescence-guided surgery

International audiencePURPOSE:Fluorescence-guided surgery (FGS) provides surgeons with new opportunities to improve real-time cancer nodule detection and tumor margin visualization. Currently, the most important challenge in this field is the development of fluorescent dyes that specifically target tumors. We developed, characterized and evaluated SGM-101, an innovative antibody-dye conjugate in which the fluorochrome BM104, which has an absorbance band centered at 700 nm, is coupled to a chimeric monoclonal antibody (mAb) against carcinoembryonic antigen (CEA).METHODS:The dye to mAb ratio, binding to CEA and photobleaching of SGM-101 were determined. FGS was performed and results analyzed using different mouse models of human digestive tumors.RESULTS:SGM-101 allowed the detection of tumor nodules in three different colon cancer models: LS174T human colorectal adenocarcinoma cell-induced peritoneal carcinomatosis (PC) and liver metastases, and orthotopic grafts of HT29 human colorectal adenocarcinoma cells. In the PC model, submillimeter-sized nodules were detected during SGM-101-based FGS and SGM-101 predictive positive values ranged from 99.04% to 90.24% for tumor nodules >10 mg and nodules <1 mg, respectively. Similarly, in the orthotopic model of pancreatic cancer using BxPC3 (pancreas adenocarcinoma) cells, SGM-101 could clearly delineate tumors in vivo with a tumor-to-background ratio of 3.5, and penetrated in tumor nodules, as demonstrated by histological analysis. Free BM105 dye (BM104 with an activated ester for conjugation to the antibody) and an irrelevant conjugate did not induce any NIR fluorescence.CONCLUSION:These preclinical data indicate that SGM-101 is an attractive candidate for FGS of CEA-expressing tumors and is currently assessed in clinical trials

Image-Guided Surgery in Patients with Pancreatic Cancer: First Results of a Clinical Trial Using SGM-101, a Novel Carcinoembryonic Antigen-Targeting, Near-Infrared Fluorescent Agent

International audienceBACKGROUND:Near-infrared (NIR) fluorescence is a promising novel imaging technique that can aid in intraoperative demarcation of pancreatic cancer (PDAC) and thus increase radical resection rates. This study investigated SGM-101, a novel, fluorescent-labeled anti-carcinoembryonic antigen (CEA) antibody. The phase 1 study aimed to assess the tolerability and feasibility of intraoperative fluorescence tumor imaging using SGM-101 in patients undergoing a surgical exploration for PDAC.METHODS:At least 48 h before undergoing surgery for PDAC, 12 patients were injected intravenously with 5, 7.5, or 10 mg of SGM-101. Tolerability assessments were performed at regular intervals after dosing. The surgical field was imaged using the Quest NIR imaging system. Concordance between fluorescence and tumor presence on histopathology was studied.RESULTS:In this study, SGM-101 specifically accumulated in CEA-expressing primary tumors and peritoneal and liver metastases, allowing real-time intraoperative fluorescence imaging. The mean tumor-to-background ratio (TBR) was 1.6 for primary tumors and 1.7 for metastatic lesions. One false-positive lesion was detected (CEA-expressing intraductal papillary mucinous neoplasm). False-negativity was seen twice as a consequence of overlying blood or tissue that blocked the fluorescent signal.CONCLUSION:The use of a fluorescent-labeled anti-CEA antibody was safe and feasible for the intraoperative detection of both primary PDAC and metastases. These results warrant further research to determine the impact of this technique on clinical decision making and overall survival

Carcinoembryonic Antigen–Related Cell Adhesion Molecule Type 5 Receptor–Targeted Fluorescent Intraoperative Molecular Imaging Tracer for Lung Cancer

International audienceImportance Localization of subcentimeter ground glass opacities during minimally invasive thoracoscopic lung cancer resections is a significant challenge in thoracic oncology. Intraoperative molecular imaging has emerged as a potential solution, but the availability of suitable fluorescence agents is a limiting factor. Objective To evaluate the suitability of SGM-101, a carcinoembryonic antigen–related cell adhesion molecule type 5 (CEACAM5) receptor–targeted near-infrared fluorochrome, for molecular imaging–guided lung cancer resections, because glycoprotein is expressed in more than 80% of adenocarcinomas. Design, Setting, and Participants For this nonrandomized, proof-of-principal, phase 1 controlled trial, patients were divided into 2 groups between August 1, 2020, and January 31, 2022. Patients with known CEACAM5-positive gastrointestinal tumors suggestive of lung metastasis were selected as proof-of-principle positive controls. The investigative group included patients with lung nodules suggestive of primary lung malignant neoplasms. Patients 18 years or older without significant comorbidities that precluded surgical exploration with suspicious pulmonary nodules requiring surgical biopsy were included in the study. Interventions SGM-101 (10 mg) was infused up to 5 days before index operation, and pulmonary nodules were imaged using a near-infrared camera system with a dedicated thoracoscope. Main Outcomes and Measures SGM-101 localization to pulmonary nodules and its correlation with CEACAM5 glycoprotein expression by the tumor as quantified by tumor and normal pulmonary parenchymal fluorescence. Results Ten patients (5 per group; 5 male and 5 female; median [IQR] age, 66 [58-69] years) with 14 total lesions (median [range] lesion size, 0.91 [0.90-2.00] cm) were enrolled in the study. In the control group of 4 patients (1 patient did not undergo surgical resection because of abnormal preoperative cardiac clearance findings that were not deemed related to SGM-101 infusion), the mean (SD) lesion size was 1.33 (0.48) cm, 2 patients had elevated serum CEA markers, and 2 patients had normal serum CEA levels. Of the 4 patients who underwent surgical intervention, those with 2+ and 3+ tissue CEACAM5 expression had excellent tumor fluorescence, with a mean (SD) tumor to background ratio of 3.11 (0.45). In the patient cohort, the mean (SD) lesion size was 0.68 (0.22) cm, and no elevations in serum CEA levels were found. Lack of SGM-101 fluorescence was associated with benign lesions and with lack of CEACAM5 staining. Conclusions and Relevance This in-human proof-of-principle nonrandomized controlled trial demonstrated SGM-101 localization to CEACAM5-positive tumors with the detection of real-time near-infrared fluorescence in situ, ex vivo, and by immunofluorescence microscopy. These findings suggest that SGM-101 is a safe, receptor-specific, and feasible intraoperative molecular imaging fluorochrome that should be further evaluated in randomized clinical trials. Trial Registration ClinicalTrials.gov Identifier: NCT04315467ClinicalTrials.gov identifier: NCT04315467