Heart imaging contrast agents need to be subjected to more studies in order to insure their safety, a Food & Drug Administration (FDA) advisory panel said yesterday. The contrast agents, sold under the brand names Definity and Optison, have been linked to more than 200 serious cardiac reactions and 11 deaths.
Definity, marketed by Lantheus Medical Imaging, and Optison, distributed by GE Healthcare, are used during echocardiograms, ultrasound imaging procedures that take a detailed, moving picture of the heart. In October 2007, the FDA said that it knew of at least 7 deaths associated with the administration of either Definity or Optison. Four of those fatalities occurred either during infusion or within 30 minutes following the administration of the contrast agent. The FDA said that most of the serious but non-fatal reactions also occurred in the same time frame.
As a result of these reports, the FDA requested that the labeling on Definity and Optison be modified to include a black box warning about the cardiac problems associated with these agents. The agency also said that Definity and Optison should not be used in who were acutely ill, such as those with congestive heart failure.
However, many cardiologists complained that that restriction robbed them of an important diagnostic tool. Last month, in response to those complaints, the FDA dropped the ban on giving the agents to acutely ill patients. The FDA also changed monitoring requirements for the drugs. The black box warning had originally called for monitoring all patients for 30 minutes after they receive the agents, but the revised warning said only patients with pulmonary hypertension or unstable cardiopulmonary conditions need to be monitored.
But the agency continued to be concerned about the safety of Definity and Optison, and earlier this week said that Definity had been linked to four more deaths since October 2007.
Yesterday, the FDA convened an advisory panel of outside medical experts to discuss the heart imaging agents. The agency wanted advice on what safety issues to consider as companies seek to use imaging agents to diagnose other conditions such as liver problems.
The panel said that ideally, companies selling or seeking to sell such contrast agents would launch a randomized placebo-controlled study of thousands of patients to assess the potential for heart risks. However, the panel also said the companies could conduct less-thorough observational studies if the other was not practical.
According to Dwaine Rieves, the FDA’s director of medical imaging products, both GE Healthcare and Lantheus have already agreed to review post-marketing data for safety issues. But he said that that the panel’s recommendations could affect the advice given to companies seeking future FDA approvals.
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