Heart imaging agents continue to be scrutinized by the FDA. Source: Visionary Surgery

After relaxing its black-box warning for echocardiography contrast agents in May, the FDA Tuesday called for more studies to determine their safety and effectiveness due to reports of more agent-related deaths.

An FDA panel composed of outside medical experts met Tuesday to discuss contrast agents, including how the agency should assess the drugs' safety, in particular, GE Healthcare’s Optison and Lantheus Medical Imaging’s Definity, the only two FDA-approved echocardiography contrast agents. The panel did not vote on any regulatory action.

In October 2007, the agency added a black-box warning on ultrasound contrast agents, after receiving about 200 reports of serious allergic reactions, seven of which resulted in death.

Since October, the FDA has approved labeling changes for Definity that remove most of the warnings added in October, and the agency is working with GE to make similar changes for Optison, which has caused GE to update its prescription information.

Panel members agreed that “psuedo-complications” prompted the deaths and other adverse events, but questioned the drugs’ effectiveness in saving patients’ lives, prompting some to suggest that the FDA change the pre-approval guidelines.

The current guidelines require companies to prove anatomical benefits before approval, said Dwaine Rieves, MD, director of the FDA’s division of medical imaging, during the meeting. Rieves told the panel that the agency wanted advice on what safety concerns to consider as companies seek expanded indications for the agents. 

On Friday, the FDA reported that it has received four reports of patients dying since October 2007 after receiving an echocardiography study with Definity.

One patient with congestive heart failure died within five minutes of receiving the drug; another had a cardiac arrest within minutes after administration of Definity and was revived, according to the FDA report.

In the report, the agency noted that “post-marketing reports of serious adverse reactions over the recent past have mainly cited the use of Definity, since Optison was not marketed between November 2005 and late October 2007.”

The FDA said it is working with the Optison and Definity manufacturers to develop a risk assessment and management program, which has resulted in the commencement of two clinical studies.