FDA Approves New Radioactive Diagnostic Imaging Agent to Help Locate Lymph Nodes in Patients with Certain Cancers
The FDA has approved technetium Tc 99m tilmanocept (Lymphoseek Injection), a radioactive diagnostic imaging agent that helps doctors locate lymph nodes in patients with breast cancer or melanoma who are undergoing surgery to remove tumor-draining lymph nodes.
Tilmanocept is an imaging drug that helps locate lymph nodes; it is not a cancer-imaging drug. It is the first new drug used for lymph node mapping to be approved in more than 30 years. Other FDA-approved drugs used for lymph node mapping include sulfur colloid (1974) and isosulfan blue (1981).
“Removal and pathological examination of lymph nodes draining a primary tumor is an important diagnostic evaluation for some patients with breast cancer or melanoma,” said Shaw Chen, MD, Deputy Director of the Office of Drug Evaluation IV in the FDA’s Center for Drug Evaluation and Research. “To use [tilmanocept], doctors inject the drug into the tumor area and later, using a handheld radiation detector, find lymph nodes that have taken up [the agent’s] radioactivity.”
Safety and Efficacy
Tilmanocept’s safety and effectiveness were established in two clinical trials of 332 patients with melanoma or breast cancer. All patients were injected with the agent and blue dye, another drug used to help locate lymph nodes.
Surgeons subsequently removed suspected lymph nodes for pathologic examination. Confirmed lymph nodes were examined for their content of blue dye and/or tilmanocept. Results showed the agent and blue dye had localized most lymph nodes, although a notable number of nodes were localized only by tilmanocept.
The most common side effects identified in clinical trials was pain or irritation at the injection site.
Technetium Tc 99m tilmanocept is marketed by Navidea Biopharmaceuticals, Inc, based in Dublin, Ohio. ■