Medical Device Daily

To treat atrial fibrillation (AF), the main therapy is often medication, with a drug like Coumadin. However, in about 60% of patients with AF, medication does not stop the symptoms, primarily an uncontrollable rapid heartbeat that can produce various co-morbidities and result in a serious decline in health.

This problem is driving companies to seek a variety of treatments, most, to date, being fairly invasive.

Among the several companies seeking a less-invasive treatment for AF is ProRhythm (Ronkonkoma, New York), Richard Fischer, company CFO, told Medical Device Daily.

The company reported that the first patient in its first pivotal trial recently was treated using its High Intensity Focused Ultrasound (HIFU) Ablation System, meaning that the energy produced and used is focused in a small area.

The initial procedure — which the company characterized as a critical milestone for it — was performed at Beaumont Hospital (Royal Oak, Michigan).

“Ablations for AF are done on an off-label basis by very experienced electrophysiologists today by using a standard RF [radiofrequency] catheter and trying to do point-by-point ablations around vein osteums, so they try to connect the dots of the [pulmonary vein],” Fischer said.

ProRhythm’s product involves the use of a balloon catheter, used to apply a “relatively short burst of [ultrasound] energy, between 40 and 60 seconds,” to create a lesion that “blocks the extraneous electrical signals” that ultimately are thought to cause AF.

The company compares this to the focusing of sunlight to create an intense spot of heat as a method of ablation, targeting a site that avoids damage to surrounding tissue.

The AF ablation procedure is one of what are commonly called Pulmonary Vein Isolation (PVI), the company said, although none of these treatments have been approved by the FDA. Rather, like some drugs, they are used in an “off-label” basis.

During this first procedure in the pivotal trial at Beaumont Hospital, performed by Dr. David Haines, the physician was able to position the HIFU Ablation Catheter at each of the four pulmonary veins and successfully block electrical conduction from each of the pulmonary veins to the left of the heart.

“The system was able to deliver energy to the intended locations in a highly efficient and effective manner,” said Haines, director of the Heart Rhythm Center at Beaumont. “We are hopeful that the HIFU procedure will allow the patients to lead a life that is free of atrial fibrillation.”

Fischer told MDD that the study — in which ProRhythm intends to enroll about 100 patients — will likely take a year to complete, depending on the time required for full enrollment. At that point, the FDA is requiring 12-month follow-up on all patients, at best taking the company through the end of 2008 for submission to the FDA.

“The initiation of the pivotal study is a critical step along the path toward commercialization of our HIFU technology in the” U.S. said Reinhard Warnking, president/CEO of ProRhythm. “The acute results of the first procedure mirror the results seen in the feasibility phase of the trial.”

Electrophysiologist Dan Dan, MD, who practices at Piedmont Hospital (Atlanta), is participating in the ProRhythm clinical trial. The problem of AF is only going to increase with the aging population, he said, because it is a condition that is “more prevalent with advancing age.”

The good news in that scenario is that people are more aware of AF and recognize its symptoms than they were 10 years ago, he said.

Dan said he wanted to participate in ProRhythm’s trial because he was “very interested” in its technology, describing it as “relatively straightforward.”

“It’s a very powerful technology and makes very good lesions, [that is] lesions that can be controlled . . . [which] is very important to long-term success,” he said. “And also the use of the balloon actually facilitates good lesions in the left atrium that isolates the pulmonary veins, which are the major culprits for this disease.”

Formerly named TransSurgical, the company adopted the name ProRhythm in 2004.

Fischer said that originally the company had more than one focus, as suggested by the name TransSurgical, and had pursued the thought that by administering focused ultrasound extracorporeally on a tumor site, it could produce a viable treatment not requiring incisional surgery.

Fischer said that when Warnking joined the company in 2001, he shifted the focus to HIFU for AF, having decided that was the “best opportunity” for commercial success.

The company said that globally, more than 6 million people are affected by AF but that drugs and other available treatments are very expensive and frequently don’t help the problem.

“That’s why a lot of the emerging medical device companies are trying to find the so-called ‘Holy Grail’ of a minimally-invasive device that could [provide] hopefully a permanent cure for it and avoid the use of drugs and all the side effects,” Fischer told MDD.

Other companies are pursuing a similar strategy of seeking minimally-invasive “cures” for AF. Among those are CryoCor (San Diego) and CryoCath (Montreal), which Fischer said were both conducting pivotal trials currently for their treatments which use freezing energy to create lesions on the pulmonary veins.

In November, CryoCor filed a premarket application (PMA) with the FDA for the treatment of atrial flutter using its disposable catheter system in the cryoablation treatment. It said at the time that it was also conducting a pivotal trial using the treatment for AF (MDD, Nov. 30, 2006).

At about the same time, CryoCath said it had received notification from the FDA allowing the company to expand its STOP trial for its pivotal investigational device, also using cryoablation. The company said it can now enroll up to 150 patients in up to 20 centers (MDD, Nov. 30, 2006).