SILVER SPRING, Md.--(BUSINESS WIRE)--A representative of the International Contrast Ultrasound Society (ICUS) told a Food and Drug Administration advisory panel Monday that ultrasound contrast agents are safe and useful diagnostic tools.
New studies reflecting use in more than 5 million patients show that ultrasound contrast agents present an extremely small risk to patients while improving the accuracy of ultrasound diagnoses and, in many cases, avoiding the need for risky and expensive downstream testing, Dr. Paul Grayburn told a joint meeting of the FDA's Renal Drugs Advisory Committee and the Drug Safety and Risk Management Advisory Committee. Grayburn, a professor of medicine and cardiologist at Baylor University Medical Center in Dallas, is a member of the ICUS executive board and associate editor of the Journal of the American College of Cardiology. He also serves as a reviewer for numerous professional journals and the National Institutes of Health.
A majority of advisory committee members appeared to vote in favor of a non-binding recommendation to remove boxed warnings on both of the ultrasound contrast agents approved for use in the United States: Definity (Lantheus Medical) and Optison (GE Healthcare). The informal hand vote taken at the end of the meeting was in response to a question posed by the FDA and based on "the totality of all new safety information."
While some panelists expressed concerns relating to statistical limitations of certain studies, others expressed confidence in the overall safety profile of the contrast agents and concluded that labeling warnings outside the "black box" were sufficient and appropriate -- especially when compared to greater risks associated with alternative imaging.
"We are concerned that overuse of boxed warnings may diminish their overall effectiveness and, in specific cases, may jeopardize appropriate care by unduly chilling the use of a product that is quite safe and can save lives," Grayburn said after the meeting. "This would be especially problematic as decision-making moves into the hands of hospital risk management committees."
Ultrasound contrast agents may be injected into an arm vein during an echocardiogram when images are inconclusive -- which occurs in an estimated 10-30 per cent of patients, according to Grayburn. He said that ultrasound contrast agents do not contain dye, and do not expose patients to ionizing radiation or the risk of nephrotoxicity. He told the panel that these products are significantly safer than alternative imaging, and said the panel should consider the risks associated with non-use of contrast agents -- including risks of misdiagnosis and downstream alternative testing or procedures.
Grayburn said that the Intersocietal Commission for Accreditation of Echocardiography Laboratories (ICAEL) has independently examined the risks and benefits of ultrasound contrast agents and, as of July 2010, now mandates their use in all suboptimal echocardiograms. Grayburn stated that ICAEL's standard of care is consistent with the totality of current safety information.
ICUS is an international professional society comprised of cardiologists, radiologists, vascular imaging specialists, and other imaging professionals. Launched in 2008, ICUS has members in more than 55 countries and is the only professional society exclusively focused on use of ultrasound contrast agents to improve patient care.