Boston Scientific has announced positive 12-month results from the PINNACLE FLX clinical trial assessing the safety and efficacy of the next-generation WATCHMAN FLX Left Atrial Appendage Closure (LAAC) Device for patients with non-valvular atrial fibrillation (NVAF). Presented as a late-breaking clinical trial at HRS 2020 Science, the study evaluated performance of the WATCHMAN FLX device as an alternative to oral anticoagulation therapy, including non-vitamin K antagonist oral anticoagulants (NOACs), for stroke risk reduction in patients with NVAF.
The prospective, non-randomised PINNACLE FLX trial included 400 patients in the USA with NVAF who were eligible for anti-coagulation therapy to reduce the risk of stroke but had an appropriate rationale to seek a non-pharmaceutical alternative. The trial met its primary safety endpoint—defined as occurrence of a major procedure-related complication within seven days following the procedure or time of hospital discharge, whichever was later—with a low adverse event rate of 0.5%. The study also met its primary effectiveness endpoint, with data demonstrating a 100% rate of effective LAA closure at 12 months post-procedure with peri-device flow <5mm.
“We believe the next-generation WATCHMAN FLX technology contributed to the excellent overall clinical performance seen in this study, notably the very low rate of safety events and high rate of effective closure,” said Shephal Doshi, the study’s co-principal investigator and cardiologist at Pacific Heart Institute at Providence St. John’s Health Center, Santa Monica, USA. “In fact, we saw that 90% of patients showed absolutely no detectable leakage around the device at their 12-month follow up, which compares favourably to the rates of peri-device flow observed in the PROTECT-AF and PREVAIL trials with the predicate WATCHMAN device and may translate into improved long-term clinical outcomes.”
Data from the trial also demonstrated an implant success rate of 98.8% and that no patients experienced peri-procedural death, device embolization or pericardial effusion requiring cardiac surgery, all of which is favourable in the context of previous clinical studies, Boston Scientific said in a press release announcing the results. In addition, 96.2% of patients were able to discontinue oral anticoagulation following their 45-day follow up. Secondary endpoints from the PINNACLE FLX study, including the occurrence of ischemic stroke or systemic embolism, will be reported after 24 months of patient follow-up.
“As we have seen in previous clinical trials, WATCHMAN technology is well-established as a safe and effective therapeutic option for patients with NVAF at increased risk for stroke and systemic embolism who need an alternative to a lifetime on anti-coagulant medications,” said Ian Meredith, global chief medical officer, Boston Scientific. “We are pleased with the performance exhibited by the next-generation WATCHMAN FLX device in the PINNACLE FLX study, which mirrors positive European physician experience to date and underscores our commitment to advancing this technology for safe treatment of a broader population of eligible patients with NVAF.”
The next-generation WATCHMAN FLX device received CE mark in March 2019 and is designed to advance procedural performance and safety while expanding the treatable population of patients with NVAF. The new frame allows for optimal device engagement with the tissue for long-term stability and a faster, complete seal of the LAA, Boston Scientific said in its press release.
The company plans to further evaluate the WATCHMAN FLX device for patients with NVAF via continued enrolment in the ongoing OPTION trial – comparing the device to oral anticoagulants in patients who also undergo a cardiac ablation procedure – as well as in the CHAMPION-AF clinical trial, which will study a broader anticoagulant-eligible patient population to evaluate the device against NOACs for embolic stroke prevention.