FDA Approves Revised Label for Rubidium Compound CardioGen-82

The Food and Drug Administration approved revised labeling for CardioGen-82 this month, signaling a return to the market soon for an important compound in cardiovascular nuclear medicine. CardioGen-82 consists of a small generator that’s supplied to facilities by the manufacturer every four weeks. The generator is then used to produce rubidium, a tracer material in a preferred method of cardiovascular imaging. When it comes to diagnosing myocardial profusion, rubidium has clear advantages as a tracer to technetium-99 used in SPECT exams, according to Timothy Bateman, MD, a cardiology expert at Mid American Heart Institute in Kansas City. “W can do things with it we can’t do with SPECT, such as quantify the blood flow in milliliters per minute per gram of tissue to the heart muscle,” Bateman says. “It’s extremely important for a fair subset of patients.” The Heart Institute was a pioneering user of rubidium in cardiovascular imaging since the early 1990s. It was still one of the nation’s biggest users of CardioGen-82 up until Bracco Diagnostic, the sole producer, voluntarily removed it from the market in July 2011 after warnings by the FDA. Two facilities, out of more than 150 that used the product, may have exposed patients to high levels of strontium, a byproduct of making the rubidium in the small generators on-site. Bateman says having it off the market for eight months already has probably done more harm to patients than leaving it on the market would have done. An FDA investigation earlier this year found it was mainly failure by the two facilities in their testing procedures that led to the higher exposures. As part of its relabeling, the FDA is requiring a so-called “boxed warning” and enhanced testing information. When strontium levels reach a certain limit, it triggers additional testing. “Previously, eluate testing was done only once a day; with the revised labeling, the testing is still done daily, but additional tests are performed that day if a generator eluate has reached the Alert Limit," according to an FDA press release.