The U.S. Food and Drug Administration today approved Lymphoseek (technetium Tc 99m tilmanocept) 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.
Lymph nodes filter lymphatic fluid that flows from the body’s tissues. This fluid may contain cancer cells, especially if the fluid drains a part of the body containing a tumor. By surgically removing and examining the lymph nodes that drain a tumor, doctors can sometimes determine if a cancer has spread.
Lymphoseek is an imaging drug that helps locate lymph nodes; it is not a cancer imaging drug. Lymphoseek 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, M.D., deputy director of the Office of Drug Evaluation IV in the FDA’s Center for Drug Evaluation and Research. “To use Lymphoseek, doctors inject the drug into the tumor area and later, using a handheld radiation detector, find lymph nodes that have taken up Lymphoseek’s radioactivity.”
Lymphoseek’s safety and effectiveness were established in two clinical trials of 332 patients with melanoma or breast cancer. All patients were injected with Lymphoseek 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 Lymphoseek. Results showed Lymphoseek and blue dye had localized most lymph nodes, although a notable number of nodes were localized only by Lymphoseek.
The most common side effects identified in clinical trials was pain or irritation at the injection site.
Lymphoseek is marketed by Navidea Biopharmaceuticals, Inc. based in Dublin, Ohio.