Medical Device Daily Washington Editor

GAITHERSBURG, Maryland – The circulatory systems device panel of the FDA's Center for Devices and Radiological Health met last Thursday to consider an additional indication for the CoolGard 3000 Thermal Regulating System from Alsius (Irvine, California).

The panel did not hold an approval vote on Thursday, but it did review study data and listened to a company presentation before suggesting its recommendations to Alsius.

According to the FDA presenters who reviewed the Alsius application, questions remain about the safety and effectiveness of endovascular cooling for the proposed indication.

The company appeared before the panel to revise the system's indications for use to include the induction, maintenance and reversal of mild hypothermia in the treatment of unconscious adult patients with spontaneous circulation after out-of-hospital cardiac arrest when the initial rhythm was ventricular fibrillation.

The system previously has been cleared for two separate indications.

In 2003, the CoolGard 3000 and the Cool Line Catheter Thermal Regulation System were approved for use in fever reduction in patients with cerebral infarction and intracerebral hemorrhage and requiring access to the central venous circulation and intubated and sedated (Medical Device Daily, Aug. 25, 2003).

Then, in November 2003, the system – using either the company's Icy or Fortius catheter models – was approved for use in cardiac surgery patients to achieve or maintain normal body temperature during surgery and in recovery or intensive care. It also was approved to induce, maintain, or reverse mild hypothermia in neurosurgery patients during surgery and in intensive care.

In the CoolGard system, the catheters provide a combination of central venous access and regulation of core body temperature. The catheter features heat exchange balloons in which cool or warm sterile saline continuously flows in a "closed loop" fashion.

The system remotely senses changes in patient temperature and adjusts the temperature of the sterile saline flowing within the balloons as needed.

The company says that the result is efficient regulation of patient temperature by controlling temperature from the inside-out.

Alsius presented an analysis from several surface cooling studies, along with specific clinical data using the CoolGard system from a 13-patient, uncontrolled feasibility study in the U.S., and a prospective non-randomized single-site observational registry in Europe.

Issues concerning the panel were highlighted by panelists' pointed questions about the lack of trial data – specifically that the trial enrolled so few patients and that it was not controlled. The panel urged the company to secure more system-specific data.

"I don't think there was nearly enough data provided," said John Somberg, MD, a panel member who is with the American Institute of Therapeutics (Lake Forest, Illinois).

Richard Page, MD, a physician at the University of Washington School of Medicine (Seattle) said he was "optimistic," but he would also like to see more data or a "more thorough" study.

"If we were voting today, I would vote no," said panel member Norman Kato, MD, a surgeon with the Cardiac Care Medical Group (Encino, California) "I think that the data on hypothermia is interesting, but not enough."

Brent Blumenstein, PhD, a panel member and statistician with TriArc Consulting (Seattle) took a harder line, calling the mix of data "Hamburger Helper," in that the company was taking information from many different trials and trying to present it as something more substantial than it really is.