Boston Scientific (NYSE:BSX) today released combined 5-year outcomes data from both the Prevail and Protect-AF study of its Watchman left atrial appendage closure device, touting it as a safe and effective an alternative to long-term warfarin therapy for patients with non-valvular atrial fibrillation.
Five-year data from the Prevail study was published online today in the Journal of the American College of Cardiology.
In both trials, the Marlborough, Mass.-based company compared the Watchman device to warfarin treatment for stroke prevention in patients with non-valvular AF with follow-ups out to five years. A combined analysis of both studies include data from a total of 1,114 randomized patients
For the Prevail trial, the initial composite co-primary endpoint of stroke, systemic embolism or cardiovascular and unexplained death was found to not achieve non-inferiority, while the second co-primary endpoint of post-procedure ischemic stroke and systemic embolism did achieve non-inferiority, according to study results.
Data from the Warfarin arm of the trial indicated an unusually low ischemic stroke rate of 0.73%, though after a meta-analysis, the composite endpoint was similar between groups, as was all-cause stroke.
While the ischemic stroke and systemic embolism rates were higher with the Watchman LAAC, the difference did not reach statistical significance, according to results, while differences in hemorrhagic stroke, disabling and fatal stroke, cardiovascular and unexplained death, all-cause death and post-procedure bleeding were favorable to the Watchman.
“If you look at the type of stroke, there were more ischemic strokes with the Watchman device than with Warfarin, but this did not reach a conclusive end. On the other hand, there were statistically significantly fewer hemorrhagic strokes – 80% fewer hemorrhagic strokes. That drove important clinical outcomes. There was a 55% decrease in the worst type of stroke,” Dr. Vivek Reddy told MassDevice.com in an interview.
Reddy said that despite the limited size of the Prevail study, the addition of 5-year data and the reduction of deadly strokes were a significant marker for the safety and efficacy of Boston Scientific’s LAAC device.
“The data presented today lend additional credence to the long-term safety and efficacy for the Watchman device. The totality of the data from both randomized trials and observational studies convincingly demonstrates ischemic stroke reduction similar to that observed with warfarin, when accounting for differences in CHA2DS2-VASc score,” Boston Scientific rhythm management chief medical officer Dr. Kenneth Stein said in a press release.
The company also presented a budget impact study of the Watchman device exploring straight-cost differences between its use and warfarin and non-warfarin oral anticoagulants in a poster presentation the day before, revealing a significant cost difference for not only the providers, but for patients.
Results from the comparison study, which was also led by Dr. Reddy, indicated that at 5 years, LAAC Medicare costs were $21,557, lower than non-warfarin anticoagulants, but higher than the $10,034 for warfarin therapy.
For the patient, however, Watchman LAAC was significantly lower, at $3,871 at 5 years. Warfarin therapy clocked in at $6,644 for the patient at 5 years while NOAC therapy cost patients $10,329.
Data indicated that LAAC with Watchman becomes the least costly option at 9 years and continued to be cost-saving over time, while LAAC becomes cheaper than LOAC therapy at 4 years, and also trends towards further savings.
At 10 years, LAAC with the Watchman was found to be the least costly to Medicare at $34,097, versus $40,147 with Warfarin or $65,515 with NOACs. Complications were shown to comprise 41% and 30% of LAAC and NOAC costs, respectively, compared to a much higher 83% rate with Warfarin.
“The analysis that we did up was pure how much do things cost – cost on the health system. What we did that was really interesting – we took into account that business costs are being incrementally shifted from payers to beneficiaries. We said, let’s find out what the total costs are. With the Watchman strategy, with the Warfarin strategy, or with NAOC strategies. Let’s also figure out what are the costs to insurers and what are the costs to patients? We did this at five years and at ten years because that’s standard in the field. What you see is it turns out appendage closure is actually much cheaper to the overall system. It’s cheaper also to patients,” Dr. Reddy said in an interview.
In May, Boston Scientific released 1-year results from the Ewolution registry study of its Watchman LAAC device, touting a high implant success rate and stroke reduction in patients with non-valvular atrial fibrillation patients.