|Boston Scientific's Watchman posted improved safety results in its latest trial.--Courtesy of Boston Scientific|
After all the hand-wringing over the results of its Prevail study, Boston Scientific ($BSX) revealed that Watchman proved safer than earlier data suggested, putting to rest rumors that the company was downplaying a failed trial.
According to the study, Watchman posted a higher rate of implant success in Prevail than in the previous Protect AF trial, and the device's 7-day serious complication rate dropped by 49%. Prevail missed its second efficacy endpoint, performing just about equal to standard-of-care blood-thinning drugs in preventing stroke, but it made the third, reducing the rates of ischemic stroke and systemic embolism after 18 months.
Boston Scientific is counting this as a victory. With Protect AF, the company demonstrated that Watchman could prevent strokes in atrial fibrillation patients just as well as warfarin, but the high rate of complications alarmed the FDA. Now, after slashing the number of device-related problems with Prevail, Boston Scientific is ready to pool its data and submit for agency approval.
The company estimates the market for Watchman at about $500 million a year, and, if the FDA is satisfied with the device's latest safety numbers, Watchman would be the only product of its kind on the market in the U.S. St. Jude Medical ($STJ) kicked off a pivotal trial last week for its similar Amplatzer Cardiac Plug, but is likely at least two years behind Boston Scientific.
However, because Watchman failed to beat blood thinners in efficacy, it's unlikely to kick down any doors with respect to market share. The device is well-suited for patients at high risk for bleeding or who are contraindicated for anti-coagulants, but, until Boston Scientific can demonstrate that Watchman trumps drugs in stroke prevention, the device is unlikely to become the standard of care.
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- read Boston Scientific's statement