Beyond imaging: Ultrasound microbubbles show promise for drug delivery

In a first-of-its-kind pilot study, ultrasound microbubbles typically used as a contrast agent have shown they may be able to enhance the delivery and absorption of cancer drugs in those with advanced pancreatic cancer, according to findings presented last week at the International Contrast Ultrasound Society (ICUS) annual conference in Chicago.

"Our early findings suggest that commercially-available ultrasound microbubbles, combined with a standard chemotherapy drug, may prolong survival in pancreatic cancer patients," said Odd Helge Gilja, MD, PhD, head of National Centre of Ultrasound in Gastroenterology at Haukeland University Hospital, Chair of Research at Dept. Of Clinical Medicine at University of Bergen, Norway, and President-Elect of the European Federation of Ultrasound in Medicine and Biology, in a press release.

The Phase I study included 10 patients with inoperable tumors, and all received an infusion of gemcitabine, a chemotherapy drug, followed by an infusion of Sonovue, a microbubble contrast agent. A customized ultrasound scanner was then used to induce “sonoporation,” which cause cell membranes to open and reseal to allow for enhanced delivery of the cancer drug.

Using CT to measure the tumors following treatment, Gilja and colleagues reported that preliminary results showed tumor size was reduced or growth was slowed in the patients.

While two ultrasound contrast agents—Definity (Lantheus Medical Imaging) and Optison (GE Healthcare)—are available in the U.S., the FDA has approved them for cardiac imaging only. Additional diagnostic uses are currently being reviewed, however therapeutic application of ultrasound contrast agents have not been submitted for review, according to ICUS.