Boston Scientific (NYSE:BSX) executives highlighted new data from two randomized clinical trials during an American College of Cardiology conference call, describing the results as potentially “practice transforming” for pulmonary embolism (PE) and stroke prevention in atrial fibrillation (AF). The company discussed HI-PEITHO, which evaluated ultrasound-assisted catheter-directed thrombolysis with the EkoSonic system in intermediate-risk PE, and CHAMPION-AF, which compared the WATCHMAN FLX left atrial appendage closure device with long-term oral anticoagulation in non-valvular AF.
Investor Relations Vice President Lauren Tengler said the company issued two press releases earlier in the day covering the data presentations. Management also reiterated that the call included forward-looking statements and noted it was not an offer or solicitation related to the company’s proposed transaction with Penumbra.
HI-PEITHO: EkoSonic plus anticoagulation vs anticoagulation alone
The primary endpoint was a seven-day composite of PE-related death, recurrent PE, or cardiovascular decompensation/collapse. Jaff said the trial met its primary outcome with a p value of 0.005 favoring EkoSonic plus anticoagulation over anticoagulation alone.
He also emphasized safety findings, stating that concerns around thrombolytic therapy have historically centered on bleeding and intracranial hemorrhage. According to Jaff, HI-PEITHO showed:
- No difference in major bleeding at seven days and 30 days, using either ISTH or GUSTO definitions.
- No intracranial hemorrhages in the trial.
Jaff framed the results as shifting the historical approach for intermediate-risk PE, which he characterized as “watchful waiting” with anticoagulation and monitoring.
CHAMPION-AF: WATCHMAN FLX vs oral anticoagulation at three years
Brad Sutton, Chief Medical Officer of AF Solutions, reviewed three-year data from CHAMPION-AF, which he called the largest prospective randomized trial in its space. Sutton said the study involved 141 sites globally and about 300 operators. Patients had CHA2DS2-VASc scores of 2 or greater for men and 3 or greater for women and were randomized to WATCHMAN FLX or oral anticoagulation; patients in the device arm could receive either DAPT or NOAC therapy with or without aspirin for three months.
Sutton said CHAMPION-AF met its prespecified primary efficacy endpoint of non-inferiority for a composite of cardiovascular death, stroke, and systemic embolism. He noted that event rates were low and that the “absolute difference on an annualized basis” for ischemic stroke between therapies was 0.33%.
For safety, Sutton said the primary safety endpoint was non-procedural bleeding (major and clinically relevant non-major bleeds), and that the trial demonstrated superiority for appendage closure versus anticoagulation. He stressed that clinically relevant non-major bleeds were not “nuisance bleeds,” but events that require escalation of care such as emergency room visits or medication changes.
Although procedural bleeding was not part of the primary safety endpoint, Sutton said a secondary analysis including procedural bleeding still favored WATCHMAN FLX, citing a 34% relative risk reduction in bleeding over three years versus oral anticoagulation.
Clinician perspectives: adherence, safety profile, and stroke vs bleeding trade-offs
During Q&A, study co-chair Dr. Marty Leon of Columbia University said guidelines “tend to lag behind clinical practice” and characterized the CHAMPION-AF results as a “strong endorsement” for use in a broader population than current guidance. Leon highlighted the balancing of an annualized 0.33% increase in ischemic stroke or systemic embolization versus an approximately 2.6% reduction in bleeding as a basis for “meaningful conversations with patients,” particularly given non-adherence to DOACs.
Leon also noted that in the NOAC group, about 200 patients crossed over, and said more than half of those crossovers were driven by patients or referring physicians seeking left atrial appendage closure “even before there was any data,” which he argued reflects sentiment about lifelong anticoagulation.
On adoption, Ken Stein, the company’s Chief Medical Officer, said the trial enrolled patients with low bleeding risk on average (he cited an average HAS-BLED score of 1.6) and argued an important takeaway was that “there is just a lot of clinically important bleeding” even among patients considered good candidates for NOAC therapy. Leon emphasized procedural safety, pointing to a 1% overall procedural significant complication rate in the study as supportive of broader application.
Asked about ischemic stroke rates and longer-term risk, Leon said the ischemic stroke curves showed a difference at three years of 3.2% versus 2%, with separation beginning around six months and appearing relatively flat from one to three years. Stein cautioned against over-interpreting certain endpoints at three years, noting a five-year endpoint exists because it is not adequately powered at three years.
Regulatory and reimbursement path: label expansion, CMS coverage, and market sizing
Management repeatedly pointed to expected next steps tied to broader adoption. Stein said the company believes the data support a label expansion and that Boston Scientific plans to submit to the FDA. He also said the company is working with professional societies on focused consensus updates that could come before guideline changes.
Regarding reimbursement in the U.S., Stein said that after an FDA process, the company would work with CMS to expand reimbursement through the national coverage decision (NCD), adding that the company hopes any revised NCD would cover the full label.
Sutton reiterated the company’s view of the market opportunity, stating that about 5 million patients are indicated today and that the company believes CHAMPION-AF “paves the way to quadruple that number” to 20 million by 2030 and beyond, with the bulk in the U.S. He said the company is pursuing label expansion to position the therapy as a first-line alternative to oral anticoagulation and is seeking expanded coverage from CMS and commercial payers. Tengler said the data support the company’s previously stated expectation of 20% market growth over its long-range plan.
On real-world anticoagulant adherence, Sutton said compliance in the trial approached 90% and described it as a best-case scenario, while he characterized real-world compliance as closer to 60%. He added that cost-effectiveness analyses have historically favored a one-time procedure over lifelong anticoagulation, while noting the landscape could evolve with generics and potential new drug classes such as Factor XI inhibitors.
About Boston Scientific (NYSE:BSX)
Boston Scientific Corporation (NYSE: BSX) is a global medical device company that develops, manufactures and markets a broad portfolio of products used in less-invasive medical procedures. Founded in 1979 by John Abele and Peter Nicholas, the company is headquartered in Marlborough, Massachusetts, and focuses on technologies that enable physicians to treat a wide range of cardiovascular, digestive, urologic, pulmonary and chronic pain conditions without open surgery.
Boston Scientific’s activities span product development, clinical research, regulatory affairs and commercial sales.
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