- On Wednesday, Boston Scientific will re-present data on its Watchman device to the FDA's Circulatory System Devices advisory panel.
- The Watchman is a novel cathether-delivered left atrial appendage closure device that is intended to be used in place of chronic warfarin therapy to lower risk of stroke in patients with atrial fibrillation.
- The main hurdles to approval have been related to clinical trial data, which, despite being positive at face value, are compromised by a complicated trial design and limited longer-term data.
The thought of having the Watchman as a clinical option when treating patients with atrial fibrillation (AF) is appealing—even FDA advisors are excited by the idea. But in reality, there have been many challenges.
The FDA has postponed the vote on device twice to date, pushing the development time past the 10-year mark. When results were presented from the initial phase III trial, the PROTECT AF trial, it was deemed insufficient to demonstrate long-term safety and effectiveness. The follow-up trial—the PREVAIL trial—had positive results, but had a complicated design with three co-primary endpoints and a Bayesian trial design that was hard to follow.
Although this meeting promises to be challenging, there is a chance that the Watchman may be approved thanks to the strength of the data related to reduction in bleeding and hemorrhagic stroke in patients using the device, as well as the trend toward a lower incidence of cardiovascular mortality. Furthermore, the committee has stated its intent to judge the evidence based on "the totality of data."