GAITHERSBURG, Md., April 23 - A novel parachute-shaped cardiac device is comparable to warfarin (Coumadin) for treating patients with atrial fibrillation (Afib), an FDA advisory committee decided today.
The Circulatory Devices Committee voted 7 to 5 to recommend that the FDA approve the Watchman, made by Atritech, to prevent stroke, cardiovascular death, and systemic embolic events in Afib patients.
The device is about one inch in diameter and placed across the left atrial appendage to permanently block off the left atrial appendage, thought to be the major source of thromboembolization in patients with Afib.
The company's clinical studies indicated that the device led to a 32% reduction in the combined rate of stroke, cardiovascular death, and embolic events compared with prolonged warfarin therapy, the current standard.
Overall, there was a 39% less chance of dying among patients who received the Watchman compared with those who did not, according to Atritech.
Warfarin is the current standard preventive therapy for nonvalvular Afib, but managing patients with warfarin is notoriously difficult, said Julie Swain, M.D., a cardiovascular surgeon with the FDA.
All patients in the company's trial were on warfarin for at least 45 days, making a head-to-head comparison of the Watchman versus warfarin impossible.
Artritech's trial data showed there is a 99% chance the device works just as well as warfarin, and an 84% chance it is superior.
However, the committee rejected the company's proposal to market the device as an "alternative" to warfarin.
It agreed instead that the device and the drug appear to be comparable. It recommended that the device could be approved for "warfarin-eligible" patients with nonvalvular Afib.
"The question of whether you can use this device without warfarin is really up in the air," said Dr. Swain.
The committee did not suggest other restrictions on the patient population for which the device could be approved.
The five panelists who voted against recommending approval mainly expressed worries about the higher upfront safety risks associated with the device.
Particularly concerning was the higher rate of ischemic strokes in the Watchman group compared with the warfarin-only group. There were 14 ischemic strokes in the Watchman group and five in the warfarin group (3% versus 2%).
However, the rates of more severe hemorrhagic strokes were lower with the Watchman than with warfarin-only (0.2% versus 2.5%).
The panel recommended physicians undergo a training program before implanting the device, noting poorer outcomes -- including higher rates of pericardial effusion -- in the company's trials among less-experienced operators.
"Once the early morbidity gets worked out as people get experience with this, it offers an option for people who have to stay on [warfarin] for many, many years, and they could do it more safely with this device, perhaps," said panelist Gary Abrams, a neurologist at the University of California San Francisco Medical Center.
The panel also recommended that implantation occur only at facilities with cardiac surgery capabilities and that the sponsor perform a large registry study and follow the trial's original participants for five years.
In closing remarks, panel chair William Maisel, M.D., a cardiologist at Beth Israel Deaconess Medical Center in Boston, took a look back to the novel heart device of several years ago: drug-eluting stents.
(See FDA Stent Panel Agrees that Benefits of On-Label Use Outweigh Risk)
He said the Watchman has some of the same issues that the drug-eluting stent advisory panel -- which he chaired -- grappled with: a potentially huge patient population, trials with low rates of very serious events, and a lack of postmarketing data.
"I think the lessons from that are that it may sound like a great idea to roll it out quickly, but I hope the sponsor will be careful about where the device goes," Dr. Maisel said.
The FDA is not required to follow recommendations of its advisory panels, but it usually does.