FDA clears Lymphoseek as lymph-node targeting agent

The FDA has approved an injectable diagnostic imaging agent to help physicians pinpoint lymph nodes that drain potentially invasive tumors to better manage patients with metastatic breast cancer and melanoma.

Lymphoseek (technetium Tc 99m tilmanocept) injection is indicated for breast cancer and melanoma patients scheduled for surgery to remove lymph nodes where cancer cells have likely spread to help physicians determine extent of metastases. It is common for metastatic disease to develop in lymph nodes that drain tissues where tumors are present.

Lymphoseek is not a cancer-imaging biomarker but a lymph-node targeting agent, according to the agency. Information gleaned from lymph-node removal can be used to provide better patient management, including tumor staging and therapy monitoring, and it could potentially provide more accurate patient prognoses.

The radiopharmaceutical, produced by Dublin, Ohio-based Navidea Biopharmaceuticals, is injected locally and targets receptors in lymph nodes where cancer has most likely taken up residence. A handheld radiation detector is then used to locate the distribution of radioisotopes among networks of lymph nodes.

There are other lymph-node targeting imaging agents available, including isosulfan blue, which was made available in 1981, and sulfur colloid in 1974. Lymphoseek is the first drug of its kind to be approved during the past 30 years.

FDA approval has followed two clinical trials involving 332 subjects with either breast cancer or melanoma. All patients were administered Lymphoseek, another lymph-node targeting drug and blue dye. Pathological studies concluded that both the blue dye and Lymphoseek were able to home in on patients’ lymph nodes with Lymphoseek finding greater numbers than blue dye. No major complications or adverse effects were associated with the imaging agents’ use besides localized pain where the drug was injected.