by
Brendon Nafziger, DOTmed News Associate Editor | January 16, 2012
The Food and Drug Administration said last week a preliminary investigation suggests "improper usage" of CardioGen-82 generators led to the increased patient radiation exposure that triggered
last summer's product recall.
In a safety announcement on Jan. 12, the FDA said ongoing tests carried out by the nuclear medicine agent's manufacturer, Bracco Diagnostics Inc., have shown manufacturing "deficiencies" noted by the agency do not seem related to the heightened radiation exposure detected in some patients.
"None of the tested generators showed signs of [strontium] breakthrough. FDA continues to work with the manufacturer to resolve their manufacturing deficiencies," the agency said.
CardioGen-82 generators produce rubidium-82 chloride injections, the only commercially available PET agent for myocardial perfusion studies, according to the Society of Nuclear Medicine.
Thus far, studies run by Bracco on 375 patients surveyed from 43 clinical sites identified 54 patients who needed follow-up tests because of abnormal screening results, the FDA said in its letter. However, the 54 patients come from only two sties, which lack sufficient "documentation of compliance with the CardioGen-82 labeling recommendations" for radiation overexposure testing, the FDA said.
"FDA continues to work with the manufacturer and other federal agencies to better characterize the problems that led to excessive radiation exposure to patients at certain clinical sites. FDA is also working with the manufacturer to revise the CardioGen-82 labeling to better describe how to use the generator and to implement a plan for the return of CardioGen-82 to the market," the agency said.
The CardioGen-82 generator was recalled in July, after two patients set off very sensitive radiation detectors at the U.S. border. The U.S. Dept. of Homeland Security notified the FDA, and eventually the patients -- one of whom was apparently briefly stranded in Canada -- were sent to Oak Ridge National Laboratories in Tennessee, where they underwent full-body scans.
A third patient also set off alarms, and it turned out the patients had all undergone PET stress tests using the substance several months earlier -- and two actually had their scans at the same Florida heart clinic.
The FDA said the problem that led to the recall, which was voluntarily ordered by Bracco, was likely caused by a "strontium breakthrough," meaning radioactive strontium isotopes used to create the PET agent were inadvertently injected into the patients.
However, the amount of radiation detected in the patients was low and unlikely to pose "significant risks," the FDA said.
Last month, Bracco told customers in a letter that it hopes to resume, with the FDA's permission, "controlled and phased" shipments of its generators during the first quarter.
