Phase 1 immunolymphoscintigraphy with an In-111-labeled antimelanoma monoclonal antibody

A phase 1 study was conducted using a monoclonal antimelanoma antibody-DTPA conjugate labeled with indium-111, for immunolymphoscintigraphy in patients with metastatic melanoma. The imaging agent, labeled with 1 mCi (37 MBq) In-111, was administered as an interstitial interdigital injection to six patients scheduled to undergo lymph node dissection for suspected metastatic malignant melanoma. No adverse effects were observed in any of the patients either during or after the infusion as determined by clinical and laboratory parameters. Antibodies to the murine immunoglobulin were produced in some patients. Regional lymph nodes were visualized whether tumor-bearing or not, and light microscopic autoradiography showed In-111 activity associated with histiocytes. One of two patients harboring both tumor-bearing and tumor-free lymph nodes exhibited preferential localization in tumor-bearing nodes. The authors conclude that this study demonstrates safety of the radiopharmaceutical and that further study is needed to improve its usefulness for diagnosis of lymph node metastases.