Boston Scientific sets FDA date for closely watched Watchman

Boston Scientific is preparing to make its case for Watchman to an FDA advisory panel.--Courtesy of Boston Scientific

Boston Scientific is ticking closer to judgment day for its much-scrutinized Watchman device, securing an FDA advisory hearing for a stroke-fighting implant that has faced doubts throughout its development.

The Circulatory System Devices Panel will meet Dec. 11 to vote on whether the agency should approve Watchman, taking a hard look at Boston Scientific's safety data in light of the device's 2010 FDA rejection. The agency is not required to follow the advice of its advisers but quite often does.

Watchman, designed to prevent strokes in atrial fibrillation patients, has charted an up-and-down path through development since Boston Scientific acquired the technology for $375 million in 2011. After the FDA took issue with the high rate of procedural complications in its PROTECT AF pivotal trial, Boston Scientific embarked on a new study, called PREVAIL, and brought down Watchman's 7-day serious complication rate by 49%.

On the down side, PREVAIL missed its second efficacy endpoint, finding Watchman to be just about equivalent to blood-thinning drugs in preventing strokes. However, in four-year follow-up data, PROTECT AF found Watchman to be statistically superior to drug therapy, and now Boston Scientific is counting on the combined results of both studies to shepherd its device to FDA approval.

Whether that'll be enough to please the FDA's advisers remains to be seen, and even if the device wins approval, many analysts worry that Watchman's shaky efficacy will hamper its indications, clearing it only for patients at high risk for bleeding or who can't tolerate anti-coagulants.

Watchman works by sealing off the left atrial appendage and catching blood clots before they can flow up to the brain, and, if approved, it would be the first device of its kind on the U.S. market. St. Jude Medical ($STJ) is in the midst of a pivotal trial for its similar Amplatzer Cardiac Plug, but the company is likely at least two years behind Boston Scientific.

- read the FDA's notice