UPDATE: Aug. 31, 2021: Results from Abbott Laboratories' recent Amplatzer Amulet trial may not just help the company take away market share from rival Boston Scientific but may drive growth for the entire left atrial appendage closure market.
Wall Street analysts were not necessarily surprised by the results as the FDA recently approved the device, but most were in agreement that the data could be strong enough to boost both Abbott and Boston.
J.P. Morgan analysts wrote that physicians agreed that Boston's next-gen Watchman FLX would have likely matched up better in the trial, but having a second device option was good for the market.
"Simply having another device in the bag that could be more appropriate for patients with different anatomies or who are less tolerant of oral anticoagulation is viewed as a significant win," the analysts wrote. "With all of this information taken into account, we believe the LAAC market has more than enough room for two players to see success over the coming years."
The results of the head-to-head trial with Boston's Watchman device were published Monday in the journal Circulation and presented at the European Society of Cardiology Congress.
Amulet was non-inferior to Watchman for the primary safety endpoint, according to the data. Major bleeding was similar between the two devices at 10.6% for Amulet and 10% for Watchman, as was all-cause death at 3.9% and 5.1%, respectively. Procedure-related complications were higher for Amulet at 4.5% compared to 2.5% for Watchman.
Abbott plans to focus its initial launch at larger centers in the third quarter and then expand to a broader launch in the fourth quarter, according to J.P. Morgan.
"Management highlighted that it already had a large and established salesforce ready as of today, with plans to further expand it as the launch ramps and we approach future catalysts such as [clinical trials] CATALYST and CHAMPION that would represent major steps towards making LAAC more of a standard of care," the analysts wrote.
J.P. Morgan and Evercore ISI agreed that the question is now if the data is strong enough to change treatment guidelines to favor LAA closure.
- Abbott Laboratories' new Amplatzer Amulet left atrial appendage (LAA) occluder has beaten Boston Scientific's rival Watchman device against one co-primary endpoint in a head-to-head clinical trial.
- The study linked Amulet to a higher rate of LAA closure than Watchman, although it was only non-inferior against the other co-primary endpoints. Fewer patients required anticoagulants after receiving Amulet.
- Abbott's data could support efforts to win market share from Boston Scientific. Recent polls have predicted Abbott will take around 20% of the market by 2023, despite most physicians at that time thinking Watchman was better at ensuring complete closures.
Abbott won FDA approval for Amulet earlier this month, ending Boston Scientific's monopoly on the LAA occluder market and setting up a fight for share with important implications for each company. Analysts expect Watchman to account for close to 10% of Boston Scientific sales by 2023. If, as two surveys of physicians suggest, competition from Amulet causes Watchman growth to slow to the high single digits, the effect of Abbott's rival will be evident in Boston Scientific's top-line results.
With the fight for market share now underway, Abbott has released data at the European Society of Cardiology Congress 2021 that could support its push to switch physicians to Amulet. The data come from a clinical trial that randomized 1,878 non-valvular atrial fibrillation patients to receive Amulet or Watchman.
In the Amulet cohort, 98.9% of patients had LAA closure at day 45, compared to 96.8% of people who received Watchman. The difference was statistically significant, meaning the trial found Amulet was superior to Watchman in that regard.
Amulet performed better than expected by some observers. In a note sent to investors earlier this month, analysts at SVB Leerink said "we do not expect the upcoming results to compare favorably against Watchman from a superiority perspective at a high level."
One outstanding question is whether LAA closure superiority will affect physician behavior. The 56 electrophysiologists polled by SVB Leerink ranked complete closure as the least important of six factors. The electrophysiologists put the most importance in the prevention of future procedures.
In terms of clinical outcomes, Amulet and Watchman are more closely matched, with Abbott finding no statistical difference in composite endpoints that looked at rates of ischemic stroke or systemic embolism through 18 months, and procedure-related complications, all-cause death or major bleeding through 12 months. The press release shared by Abbott lacks numbers for those co-primary endpoints.
Abbott did share data on oral anticoagulation regimes after implantation, a factor that the surveyed electrophysiologists ranked as the third most impactful outcome. Eighty-two percent of people were discharged on anticoagulant therapy, warfarin plus aspirin, after receiving Watchman. In contrast, 20% of Amulet patients were discharged on anticoagulants. Most Amulet patients took clopidogrel plus aspirin in a dual antiplatelet therapy.