Technetium (99mTc) fanolesomab

Technetium (^99mTc) fanolesomab (trade name NeutroSpec, manufactured by Palatin Technologies) is a mouse monoclonal antibody formerly used to aid in the diagnosis of appendicitis. It is labeled with a radioisotope, technetium-99m (^99mTc).

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History and use

NeutroSpec was approved by the U.S. Food and Drug Administration (FDA) in June 2004 for imaging of patients with symptoms of appendicitis. It consisted of a monoclonal antibody against CD15, labeled with technetium-99 so as to be visible on a gamma camera. Since anti-CD15 antibodies bind selectively to neutrophils, it could be used to localize the site of an infection.

Deaths and associated recall

The FDA received reports from Palatin of 2 deaths and 15 life-threatening adverse events in patients who had received NeutroSpec.

These events occurred within minutes of administration of NeutroSpec and included shortness of breath, low blood pressure, and cardiopulmonary arrest. Affected patients required resuscitation with intravenous fluids, blood pressure support, and oxygen. Most, but not all, of the patients who experienced these events had existing cardiac and/or pulmonary conditions that may have placed them at higher risk for these adverse events. A review of all post-marketing reports showed an additional 46 patients who experienced adverse events that were similar but less severe. All of the reactions occurred immediately after NeutroSpec was administered.^[1]

Marketing of the product was suspended in December 2005.

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