NR-LU-10 monoclonal antibody scanning: A helpful new adjunct to computed tomography in evaluating non-small-cell lung cancer

Computed tomographic scanning has improved the noninvasive staging of lung cancer but has the deficiency of not distinguishing benign from malignant lesions. This prospective trial evaluated the usefulness of a new radiolabeled monoclonal antibody, NR-LU-10, as an adjunct to computed tomography by assessing its clinical applicability and accuracy in detecting malignancy in primary lung tumors and mediastinal nodes. NR-LU-10 is a technetium 99m-labeled Fab fragment of a murine immunoglobulin G2b monoclonal antibody that recognizes a 40 kD glycoprotein expressed in lung and other epithelial cancers. Methods: (1) Patients with potentially resectable non- small-cell lung cancer were eligible; (2) all patients had computed tomographic scans of the chest; (3) whole body and single photon emission computed tomographic imaging were performed 14 to 17 hours after intravenous infusion of 20 to 30 mCi of NR-LU-10; (4) subsequent mediastinoscopy or thoracotomy with complete mediastinal nodal mapping provided pathologic correlation. Results: Twenty-four patients were entered, 14 men and 10 women. No allergic reactions or other adverse effects were seen. Interference from a prior ventilation-perfusion scan precluded adequate imaging in 1 patient, but high-quality images were obtained in the other 23 patients. The 22 primary malignant tumors all had uptake and there was no uptake in 1 lung nodule found to be benign. In 21 patients who had surgical correlation of mediastinal nodal involvement, NR-LU-10 was false-positive in 5 and false- negative in 1; results of computed tomography were false-positive in 6 and false-negative in 1. In this preliminary study, NR-LU-10 antibody scanning was safe and easily performed, it produced high-quality images of the lung and mediastinum, and it was accurate in detecting primary non-small-cell lung cancers. Further evaluation of its value in staging the mediastinum is needed, in particular, its role as an adjunct to computed tomography to help distinguish benign from malignant lesions.