June 30, 2003
As reported in the April issue of JNM’s Newsline, the FDA is requesting marketing applications from the pharmaceutical industry for products containing Prussian blue (ferric hexacyanoferrate[II]). Prussian blue is the only substance determined by the FDA to be safe and effective for treating internal contamination with isotopes such as 137Cs and thallium which are considered likely components of a “dirty bomb.” Because the FDA has already completed the safety and efficacy review work, applicants need only to submit chemistry information for the Prussian blue product they make.
A special pre-publication release from the April 2000 edition of The Journal of Nuclear Medicine (2003:44(4):45N).
On January 31 the Food and Drug Administration (FDA) issued a statement asking manufacturers to submit marketing applications for Prussian blue (ferric hexacyanoferrate[II]), which has been shown to be safe and effective in treating individuals exposed to isotopes such as 137Cs. "Today's action is part of our continuing effort to foster the development and availability of countermeasures to terrorist attacks," said Tommy G. Thompson, secretary of health and human services. "We must and will do more to prepare and protect Americans against the threat of bioterrorism."
After a review of the literature, FDA staff members determined that 500-mg Prussian blue capsules would be safe and effective for the treatment of patients with known or suspected internal contamination with radioactive thallium, nonradioactive thallium, or radioactive cesium. Prussian blue binds with radioactive particles in the gut, slows absorption through the intestines, and more rapidly eliminates the isotopes from the body. No FDA-approved treatments for internal contamination with thallium or radioactive cesium are currently available.
"FDA is working to protect U.S. citizens who may be exposed to radioactive materials released from terrorist attacks using a dirty bomb," said Dr. Mark B. McClellan, FDA commissioner. "FDA's guidance to industry and approved labeling for Prussian blue products gives manufacturers critical information necessary for producing an FDA-approved product to counter terrorism."
In determining the safety and effectiveness of Prussian blue, the FDA evaluated reports of a 1987 incident in Brazil where 250 people were contaminated with 137Cs that had been abandoned after use in a cancer clinic. The reports showed that Prussian blue reduced total exposure. Additional data from the literature, including a study of seven human volunteers contaminated with trace doses of 137Cs and reports on 19 patients in other incidents show a similar reduction in the biological half-life of the cesium after Prussian blue administration.
The FDA is encouraging the submission of New Drug Applications (NDAs) for Prussian blue drug products. Because the FDA has already completed the safety and efficacy review work, applicants need only to submit chemistry information for the Prussian blue product they make. To facilitate the process, the agency has prepared draft labeling and has published a guidance document on how to submit these applications. This guidance is available on the FDA Prussian blue information page (linked below).