Following the FDA’s request, Palatin Technologies Inc., the makers of NeutroSpec, an imaging agent used to diagnose appendicitis, are withdrawing the product from the market.
There have been now been two deaths and 20 “serious and life-threatening” complications linked to the use of the agent, according to the FDA. Those complications occurred within minutes of injection of the drug and have included cardiopulmonary failure, central nervous system reactions, and infusion reactions.
Some patients have required admission to intensive care. There have also been reports of 46 similar but less severe adverse reactions.
According to an FDA official, the “company made the decision to suspend marketing based on the events being life-threatening and the availability of other means to diagnose appendicitis that don’t carry these risks. They are urging health-care providers to stop using existing stocks, and to contact the company regarding their return."
The FDA deputy director of the Office of New Drugs, Dr. Sandra Kweder stated: "Most of the patients, but not all of them, did have some sort of underlying cardiac or lung condition that might somehow have placed them at high risk for an event but they may not have been ill at that time. We don’t know the specific way that NeutroSpec and these adverse events are related, but the consistent characteristics of events in the patients make it likely they were due to NeutroSpec.”
NeutroSpec (Technetium 99m Tc Fanolesomab) is described as a murine or mouse monoclonal antibody tagged with Technetium, a radioactive molecule. The Technetium allows the agent to be seen on an imaging scan by binding to white blood cells thereby producing a hot spot on the image that identifies the site of the infection.
NeutroSpec was approved in July 2004 by the FDA to help diagnose appendicitis in patients aged 5 years and older who don’t have the typical signs of appendicitis. The drug is manufactured by Palatin Technologies Inc. and marketed by Mallinckrodt.
The approval was based on a rather limited study of 523 individuals. In that small sample, very few patients suffered shortness of breath or declines in blood pressure. According to Kweder, "None of the cases were severe."
The FDA is urging all health-care providers to stop using NeutroSpec and to contact either Palatin Technologies Inc. or Mallinckrodt about returning existing stocks.
The FDA plans to take information about NeutroSpec to an advisory committee meeting in 2006. Kweder expects NeutroSpec to be available as an investigational new drug in cases where there are no alternatives until the FDA’s advisory committee meeting takes place.