CHICAGO — The International Contrast Ultrasound Society (ICUS) has filed two Citizen Petitions with the U.S. Food and Drug Administration seeking broader approval of contrast-enhanced ultrasound (CEUS) and the removal of boxed safety warnings from three FDA-approved ultrasound contrast agents.
The first petition requests a whole-body indication for approved microbubble ultrasound contrast agents, replacing the current organ-specific approval system. The second seeks the removal of boxed warnings from Definity, Lumason and Optison, arguing that decades of clinical experience and extensive safety research support the changes.
“Contrast-enhanced ultrasound has evolved dramatically over the past two decades, and our petitions provide strong evidence supporting the updating of regulations so they keep pace with science and clinical practice,” said Dr. Steven Feinstein, Co-President of ICUS.
Currently, FDA approvals for ultrasound contrast agents are limited to the heart and liver. ICUS maintains that scientific research and clinical experience support their use in imaging other organs, including the kidneys, pancreas, spleen, thyroid, breast and reproductive organs.
Dr. Stephanie Wilson, Co-President of ICUS and Clinical Professor of Radiology and Gastroenterology at the University of Calgary, said broader approval would allow physicians to examine multiple organs using the same contrast agent and ultrasound procedure.
“A whole-body indication would allow physicians to follow disease wherever it appears, using the same contrast agent and the same ultrasound examination,” Wilson said.
The second petition challenges boxed warnings introduced in 2007. ICUS argues that subsequent safety studies involving millions of patients demonstrate that serious adverse reactions are extremely rare. The organization is requesting that remaining safety information be moved to the standard Warnings and Precautions sections of product labels.
“The black box no longer reflects the current state of the science,” said Dr. Jordan Strom, an ICUS board member, Associate Professor of Medicine at Harvard Medical School and Director of the Echocardiography Laboratory at Beth Israel Deaconess Medical Center in Boston.
“When a warning exaggerates risk, it distorts vital information on which health care decisions are made,” Strom added.
Dr. Richard Barr, an ICUS board member and Professor of Radiology at Northeast Ohio Medical University, said the proposed regulatory changes could expand access to affordable imaging, particularly for patients with kidney disease, pregnant women and others who may face limitations with CT or MRI examinations.
CEUS uses intravenously administered, gas-filled microbubbles to improve ultrasound visualization of blood flow and tissue perfusion. The procedure can be performed at the bedside without exposing patients to ionizing radiation or using iodinated or gadolinium-based contrast agents.
ICUS said broader FDA approval could also encourage additional physician training and adoption of the technology, which is already supported for certain off-label applications by clinical guidelines and reimbursed by Medicare and many private insurers.
The petitions are requests for regulatory changes and do not alter existing FDA approvals or labeling requirements unless the agency takes action.
