Medical Device Daily

It's been a long, pothole-filled road for CryoCor (San Diego), but the company's perseverance has finally paid off with FDA approval of its Cardiac Cryoablation System for the treatment of right atrial flutter (AFL), a condition in which the upper chambers of the heart do not pump in-synch with the lower chambers.

The company yesterday reported that the FDA has granted pre-market approval (PMA) for its Cryoablation System, designed to treat cardiac arrhythmias through the use of cryoenergy, or extreme cold, to destroy targeted cardiac tissue, with the goal of restoring normal pumping action. Importantly, this is the first approval of cryoenergy for AFL treatment.

Since early last year, CryoCor has encountered a variety of challenges:

  • a "not approvable" letter from the FDA in February 2006, causing it to amend its PMA filing for the device (Medical Device Daily , Feb. 6, 2006);
  • the agency's decision to require an advisory panel meeting to review the application (MDD, April 10, 2007);
  • and the FDA posting data about the Cryoablation System on its web site — just days before the advisory panel met in June — showing that 6% of patients treated with the device experienced an adverse event (MDD, June 26, 2007), a report that caused its stock to slump.

But CryoCor trekked on, and in June the advisory panel voted 8-2 to recommend, with conditions, approval of the company's PMA application (MDD, June 29, 2007).

Getting the device through to regulatory approval proved to be easier said than done, and CryoCor's CFO Greg Tibbitts told Medical Device Daily that it was a clear compliment to the company's chief medical officer, Helen Barold, MD.

Tibbitts said Barold was able to evaluate the company's trial data to determine, first of all, if the PMA application should be amended and what additional information the company needed to give to the agency to win approval. And, "she helped build the case for the panel members as to why this is a very exciting technology."

"It's been a long road. It's been a hard road. We believe in the technology and we feel vindicated that the agency has accepted the arguments that Helen has crafted," Tibbitts said. "They evaluated the data and agreed that this is a very safe and effective device."

For Barold, the decision to continue pursuing approval of the cryoablation system for the treatment of AFL had to do with the device itself.

"We didn't feel like we should give up because this product is a good product and should be on the market," Barold told MDD.

Electrophysiologists, she added, like to have choices and the company believed they should have the option of a different energy source to treat their patients.

CryoCor plans to begin selling its cryoablation system in the U.S. over the next several months. It said it would place an initial focus on console placement in high-volume ablation centers in the U.S. and is currently evaluating its sales and marketing requirements for this strategy. The company said it has targeted an initial installed base of 120 to 160 consoles by the end of 2008, growing to roughly 300 consoles by 2010.

Barold said there are four other devices approved for the treatment of AFL, and that all of those devices use radio frequency (RF) energy to return the heartbeat to normal. CryoCor's cryoablation system is the first device approved using the freezing technique to treat the condition.

Among the companies who have received FDA approval to treat AFL with a device using RF energy is St. Jude Medical (St. Paul, Minnesota). The company reported in May that the FDA approved its uni-directional therapy Cool Path open-irrigated ablation catheter for use in patients with type 1 atrial flutter. An electrophysiologist uses a catheter to deliver radiofrequency energy to create lesions in specific areas of cardiac tissue, St. Jude said.

The lesions interrupt the abnormal electrical signals that contribute to erratic heart rhythms. An open-irrigated catheter distributes saline fluid into heart tissue through ports in the tip of the catheter to enhance cooling during ablation procedures, reducing the risk of undesirable tissue damage at the procedure site (MDD, May 10, 2007).

In comparing cryoablation to the RF method of treating AFL, Barold said both techniques are good ways of ablating cardiac tissue and achieving the goal of curing AFL. However, she said that the benefit of using cryoablation instead of RF is that it is not painful and therefore does not require as much sedation. This is especially important, she noted, for patients who have problems with sedation.

A second benefit associated with cryoablation, Barold said, is that there is no risk of clot formation along the lesion.

To date, there are no devices approved for the treatment of atrial fibrillation (AF), the other most common form of heart arrhythmia.

Now that CryoCor has received FDA approval of its system for the treatment of AFL, further approvals — including an indication for AF — may be in its future.

"It certainly can't hurt," Barold told MDD. "Once you have approval for one indication, then there is a general acceptance of the technology in general so I think it will help."

Not only will this PMA for the cryoablation system help push the company towards approval for AF, but it will also help physicians to adopt the technology, Barold said.

To comply with the approval conditions, CryoCor will implement a formal training program for clinical sites, as well as conduct a two-arm registry study of 650 patients, collecting safety and long-term effectiveness data on the use of its cryoablation system as compared to approved RF catheters in the treatment of right AFL.

CryoCor has a development deal with Boston Scientific (Natick, Massachusetts), which it reported the day after the advisory panel meeting in June. The two companies plan to collaborate for joint development of therapeutic solutions for AF (MDD, July 2, 2007).