Boston Scientific Corp. reported positive results for its Emblem subcutaneous implantable defibrillator (S-ICD) system and next-generation Watchman Flx left atrial appendage closure (LAAC) device at the Heart Rhythm Society scientific sessions, which were online only this year due to the COVID-19 pandemic. Data from the UNTOUCHED and PRAETORIAN studies of the Emblem S-ICD demonstrated an inappropriate shock-free rate of more than 95% and affirmed it as a preferred option for most ICD-indicated patients who don’t need a pacemaker. The PINNACLE FLX IDE trial showed the Watchman Flx to be a safe and effective alternative to oral anticoagulation therapies in reducing stroke risk in patients with nonvalvular atrial fibrillation.


The UNTOUCHED and PRAETORIAN data add to the body of evidence showing benefits of the Emblem S-ICD, which won U.S. FDA approval in 2016 and remains the only approved implantable defibrillator without wires touching the heart.

The global, prospective, nonrandomized UNTOUCHED trial assessed Emblem’s safety and efficacy for the primary prevention of sudden cardiac death in patients with left-ventricular ejection fraction (LVEF) less than 35%. The study met its primary endpoint with a 95.9% inappropriate shock-free rate at 18 months post-procedure, which was akin to or lower than rates seen in prior studies of S-ICDs and transvenous implantable cardioverter defibrillators (TV-ICDs).

The results showed an even higher rate – 97.6% – at one year for patients who had the Smart Pass sensing filter on the newer Emblem MRI S-ICD system. The feature filters out some of the most frequent triggers of inappropriate shocks.

“This study conclusively shows high efficacy and safety of the Emblem S-ICD and the current generation Emblem MRI S-ICD with contemporary programming, despite the patients being some of the sickest studied to date, with much lower LVEF, more hypertension and diabetes,” said Michael Gold, principal investigator and professor of medicine at The Medical University of South Carolina in Charleston. “Additionally, the rate of inappropriate shock was lower than that of many studies of TV-ICDs with contemporary programming designed to minimize this rate, validating use of the S-ICD as a first line therapy for the majority of patients in need of a device to manage risk of sudden cardiac death in the absence of pacing indications.”

The prospective, randomized, head-to-head PRAETORIAN study confirmed the S-ICD as a preferred treatment choice for ICD-indicated patients without pacing needs based on its lack of lead-related complications and infections associated with TV-ICDs, while offering comparable performance.


Watchman Flx LAAC platform. Credit: Boston Scientific Corp.

The company also reported strong 12-month results for the Watchman Flx LAAC device from the PINNACLE FLX trial. The prospective, nonrandomized study of 400 patients met its primary safety outcome of major procedure-related complication within seven days of the procedure or hospital discharge, whichever was later, with a 0.5% adverse event rte. It also achieved its main efficacy endpoint, with 100% of LAAs effectively closed at 12 months, with peri-device flow less than 5mm.

Shephal Doshi, co-principal investigator and cardiologist at Pacific Heart Institute at Providence St. John’s Health Center in Santa Monica, Calif., said data compare “favorably 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.”

While the trials were no designed to expand labeling, a Boston Scientific spokesperson told BioWorld the company is “hopeful these results may influence private insurance companies in the U.S. to replace restricted coverage with an open policy to cover S-ICD for any patient who is indicated for an ICD without a pacing indication.” The studies could also help to secure better government coverage of the system in European nations.

More studies underway

Meanwhile, Boston Scientific continues to enroll patients in the OPTION trial, which kicked off in May 2019. The randomized, controlled trial is evaluating the safety and effectiveness of the Watchman Flx LAAC platform versus first-line anticoagulants for stroke risk reduction in patients with nonvalvular atrial fibrillation (NVAF) who undergo a cardiac ablation procedure. The company expects to complete enrollment in 2021 and submit the study results to the FDA in 2024.

Another randomized, head-to-head study, CHAMPION AF, is set to launch next year to assess whether Watchman Flx is an effective first-line alternative to non-vitamin K antagonist oral anticoagulants for embolic stroke prevention in patients with NVAF. The company is currently working with the FDA to finalize details of the trial design.

The Watchman Flx LAAC platform secured CE mark approval and began a limited rollout in March of last year, with a full launch in July 2019. The next-generation device is designed to fit a host of patients with simple and complex anatomies and allows for flexibility during implantation, permitting customized placement with a fully enclosed, rounded frame. It also allows doctors to recapture and reposition the device during the procedure and is designed to improve sealing within the LAA.

“Physicians in Europe have reported satisfaction with the high rate of implant success and sealing of the LAA with the Watchman Flx device,” the spokesperson said. “We continue to plan for the device to become commercially available in the U.S. in the second half of 2020, pending FDA approval.”

Coronavirus impact

Sales of both devices have slowed as hospitals prioritize critically ill patients during the COVID-19 pandemic, the company said.

“Although Watchman procedures are largely deferrable, patients seeking this therapy are eligible based on their need for an alternative to blood thinners, and physician operators we’ve surveyed are confident that postponed procedures will be rescheduled when facility capacity and/or protocols allow for increased elective procedures,” Michael Mahoney, Boston Scientific’s president and CEO, said on a recent earnings call.

During the first three months of 2020, total revenue grew 2% to $2.5 billion, compared with the same period in 2019, but declined 2.9% organically, due to fewer elective procedures during the pandemic. Within its cardiovascular business, sales of interventional cardiology products and peripheral interventions dropped 3% and 2%, respectively. In the rhythm and neuro division, cardiac rhythm management sales fell 10%.

Mahoney predicted that recovery in CRM will be led by S-ICD replacements, the Heartlogic heart failure diagnostic tool and ongoing U.S. launches of the Ingevity+ lead and Latitude 3300 programming system with remote service offerings. The company is also eyeing a mid-year FDA clearance and launch of its Lux Dx implantable cardiac monitor.

In a recent note, Wells Fargo analyst Larry Biegelsen said CRM sales were down by about 50% in April, “The company is currently planning for the most significant negative impact of COVID-19 in Q2, which is in line with MedTech peers that have reported earnings thus far,” he wrote, with a year-over-year decline in the third quarter as well before returning to growth in the fourth quarter.

The investment banking firm lowered its 2020 revenue estimate for Boston Scientific by $970 million to $9.4 billion.

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