01—Abstract
Summary
Summary of the 8-K filed March 30, 2026. Cited figures are marked; the original filing is the authoritative source.
Boston Scientific (BSX) furnished an 8-K on March 30, 2026 disclosing two late-breaking clinical trial results presented at ACC.26 on March 28, 2026, and simultaneously published in The New England Journal of Medicine.
No financial results, guidance changes, or deal terms were disclosed; the filing is purely clinical and regulatory-pipeline news furnished under Item 8.01 (Other Events). The HI-PEITHO trial evaluated the EKOS Endovascular System (ultrasound-facilitated catheter-directed thrombolysis) in 544 patients with intermediate-risk pulmonary embolism. The EKOS plus anticoagulation arm achieved a composite primary endpoint event rate of 4.0%a versus 10.3% for anticoagulation alone (P=0.005), a 61% relative reduction, with no intracranial bleeding through 30 days.
Management is positioning the data to support EKOS plus anticoagulation as a first-line therapy, which would challenge the current anticoagulation-only standard of care. The CHAMPION-AF trial evaluated the WATCHMAN FLX left atrial appendage closure device against NOACs in 3,000 patients with non-valvular atrial fibrillation.
The device was statistically superior on non-procedural bleeding (10.9%b vs. 19.0%) and non-inferior on stroke, cardiovascular death, or systemic embolism (5.7% vs. 4.8%) at 36 months. Management plans to use these data to seek an expanded indication and coverage as a first-line stroke-prevention option, a potentially significant commercial opportunity for the WATCHMAN franchise, though regulatory and reimbursement outcomes remain uncertain and the trial's efficacy was non-inferior rather than superior.
02—Key points
Key Highlights
- HI-PEITHO (EKOS system, intermediate-risk PE, n=544): primary composite endpoint 4.0% vs. 10.3% for anticoagulation alone (P=0.005), a 61% relative reduction; cardiorespiratory decompensation 3.7% vs. 10.3%; no brain bleeds through 30 days.
- CHAMPION-AF (WATCHMAN FLX vs. NOACs, n=3,000): met all primary and secondary endpoints at 36 months, with superior non-procedural bleeding protection (10.9% vs. 19.0%, a 45% relative reduction).
- CHAMPION-AF efficacy was non-inferior, not superior: stroke, CV death, or systemic embolism 5.7% vs. 4.8% (P<0.001 for non-inferiority as reported).
- Management intends to use CHAMPION-AF data in a submission to expand the WATCHMAN indication and coverage to first-line stroke risk reduction, potentially supporting updated clinical guidelines globally.
- Both trials were presented as late-breaking sessions at ACC.26 and published simultaneously in The New England Journal of Medicine, lending high-profile peer-reviewed validation.
- The filing contains no quantitative financial results, revenue impact, guidance update, or regulatory approval; commercial impact is not yet quantified.
- Several investigators disclosed as paid consultants to Boston Scientific, a potential consideration when weighing the independence of trial presentations.
03—Questions
Frequently Asked Questions
Does this 8-K include any financial results or guidance changes?
No. The filing is furnished under Item 8.01 (Other Events) and only attaches two press releases on clinical trial results. It contains no earnings, revenue, margin, or guidance information.
What is the commercial significance of the CHAMPION-AF results?
If approved, an expanded first-line indication would open WATCHMAN use to patients who currently take NOACs, a large potential patient pool. However, the trial showed non-inferiority on efficacy, and any label expansion, guideline update, and reimbursement coverage depend on future FDA and payer decisions that are not guaranteed or timed in this filing.
How strong is the HI-PEITHO evidence for EKOS?
The trial was randomized and controlled, met its primary endpoint with a statistically significant result (P=0.005), and was published in NEJM. Its 544-patient sample across 59 sites is meaningful but moderate in size, and follow-up extends to one year, so longer-term outcomes remain to be reported.
What are the main risks or limitations investors should consider?
Key considerations include the evolving competitive landscape against NOACs and other PE and LAAC therapies, uncertainty around regulatory and reimbursement outcomes, the non-inferior (rather than superior) efficacy signal in CHAMPION-AF, and the fact that the trials were sponsored or partly consulted by the company. The filing's forward-looking statements caution that results may differ materially.
Is there any new information about the timing of regulatory submissions?
The press release says the CHAMPION-AF data will be used in a submission to expand the indication, but it does not specify a filing date, expected approval timeline, or whether a submission has been made. Investors should monitor future earnings calls and regulatory updates for timing.
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