Members of the US Food and Drug Administration (FDA) Circulatory System Devices Panel of the Medical Devices Advisory Committee have voted in favour of the Watchman left atrial appendage closure (LAAC) device (Boston Scientific), by a close vote of 6 to 5 (with 1 abstention) concluding that the potential benefits of Watchman outweigh the potential risks. Furthermore, the Panel voted that there is reasonable assurance that the device is safe (12 yes to 0 no). However, on the question of reasonable assurance of effectiveness, the Panel vote was unfavourable (6 yes to 7 no).
The Committee’s vote followed a review of the most recent clinical data and analysis from two randomised control trials, PROTECT AF and PREVAIL, as well as from the CAP (Continued access protocol) and CAP2 registries.
Boston Scientific is seeking approval for Watchman for the indication of prevention of thromboembolism in patients with non-valvular atrial fibrillation.
The Panel provided substantial input and guidance related to the proposed Indications for Use and target patient population. According to a company press release, there was widespread agreement among the Panel members that Watchman provides a much needed alternative to long-term anticoagulation for some patients. While not bound by this vote, the FDA takes Advisory Panel comments and recommendations into account when reviewing the Watchman device application.
“There is a strong clinical need for a proven device alternative to long-term warfarin therapy for my high stroke risk patients with non-valvular atrial fibrillation,” says Vivek Reddy, director of the Cardiac Arrhythmia Service at Mount Sinai Medical Center and co-principal investigator of the PROTECT AF and PREVAIL studies of Watchman. “I am encouraged that the Panel recognised the importance of having the Watchman device as an option for appropriate patients.”
The FDA’s Circulatory System Devices Panel of the Medical Devices Advisory Committee met previously in two occasions to vote for the Watchman device approval. In 2009, the Panel voted in favour of the device approval (7 to 5). The Panel also recommended the creation of a registry and extended follow-up of the current clinical trials. In December 2013, with partial results from PREVAIL, the Panel voted favourably by a majority (13 to 1) that the benefits of the device outweighed the risks. The Panel also voted favourably (13 to 1) on its safety and efficacy (13 to 1). The third meeting was called to give the FDA Panel more complete follow-up from PREVAIL. According to a report by Heart.org, these data from PREVAIL include eight new ischaemic strokes seen among the patients treated with Watchman compared with zero in the comparator group. In the initial PREVAIL results one of two primary endpoints were met; but now with the longer follow-up including the ischaemic stroke data, the report of Heart.org states that neither of the primary efficacy endpoints met the pre-specified non-inferiority endpoint.
The Watchman device was approved for sale in Europe in 2005 and is currently approved in more than 70 countries worldwide. In the USA, the Watchman device is investigational and not available for sale.