SGM-101: Fluorescent Agent in Intraoperative Lung Cancer Resection Imaging

In JAMA Network Open, researchers evaluated SGM-101, a carcinoembryonic antigen-related cell adhesion molecule type 5 (CEACAM5) receptor-targeted near-infrared fluorochrome, as a fluorescent agent in intraoperative molecular imaging to improve localization of subcentimeter ground glass opacities during minimally invasive thoracoscopic lung cancer resections.

According to the study’s lead author, Feredun Azari, the team was able to show promising SGM-101 localization to CEACAM5-positive turmos with real-time detection of near-infrared fluorescence in situ, ex vivo, and with immunofluorescence microscopy during lung cancer surgery.

This non-randomized, proof-of-principal controlled trial enrolled patients with known CEACAM5-positive gastrointestinal tumors indicative of lung metastasis as positive controls, and patients with lung nodules suggestive of primary lung malignant neoplasms as the investigative group.

Novel Fluorescent Agent Shows Promise in Lung Cancer Resection

Participants were infused with 10 mg SGM-101 up to 5 days before the index resection, and pulmonary nodules were imaged with a near-infrared camera system including a dedicated thoracoscope. The primary end point of the trial was localization of SGM-101 to pulmonary nodules and its association with CEACAM5 glycoprotein expression in the tumor.

The 5 male and 5 female patients enrolled in the phase I study had a median age of 66 years (interquartile range [IQR], 58-69) and a combined total of 14 lesions with median lesion size of 0.91 cm (IQR, 0.90-2.00). One patient in the control group did not undergo surgery due to cardiac clearance findings unrelated to SGM-101.

In the remaining 4 control patients, the mean lesion size was 1.33 ± 0.48 cm, 2 patients had elevated serum CEA, and 2 had normal serum CEA. The authors reported that patients with 2+ and 3+ tissue CEACAM5 expression demonstrated “excellent tumor fluorescence,” with a mean tumor-to-background ratio of 3.11 ± 0.45 cm.

Comparatively, in the investigation arm, the mean lesion size was 0.68 ± 0.22 cm and no increases in serum CEA levels were observed. Of note, the absence of SGM-101 fluorescence was associated with benign lesions and lack of CEACAM5 staining.

Ultimately, “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,” the authors summarized.

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