Boston Scientific announces strategic investment in MiRus LLC

Rhea-AI Summary

Boston Scientific (NYSE: BSX) agreed to invest $1.5 billion for an approximately 34% stake in MiRus, gaining an exclusive option to acquire its SIEGEL balloon-expandable TAVR system. The nickel-free valve uses a proprietary rhenium alloy and is being studied in the STAR pivotal trial in up to 1,025 patients.

Boston Scientific may later acquire 100% of the MiRus TAVR business through additional cash payments totaling $3 billion, plus potential sales-based and valve-asset payments. The company expects the 2026 earnings per share impact to be immaterial. The SIEGEL TAVR system remains investigational and not yet approved.

Positive

• Invests $1.5 billion for approximately 34% equity stake in MiRus
• Secures exclusive option to acquire MiRus TAVR business for $3 billion
• Option structure could lead to 100% ownership of SIEGEL TAVR business
• STAR pivotal trial plans enrollment of up to 1,025 severe aortic stenosis patients
• Potential future payments tied to SIEGEL TAVR net sales create upside alignment

Negative

• SIEGEL TAVR system is investigational and not approved in any country
• Total cash outlay could reach at least $4.5 billion if option exercised
• Investment expected to be immaterial to adjusted earnings per share in 2026

News Market Reaction – BSX

+6.15%

87 alerts

+6.15% Session close to close

+2.7% Peak in 5 hr 18 min

$83.71B Market Cap

0.5x Rel. Volume

In the May 18 session, BSX gained 6.15%, reflecting a notable positive market reaction. Argus tracked a peak move of +2.7% during that session. Our momentum scanner triggered 87 alerts that day, indicating high trading interest and price volatility.

Data tracked by StockTitan Argus on the day of publication.

Market Context

The stock moved +6.2% in the session following this news. A strong positive reaction aligns with Bos...

Analysis

The stock moved +6.2% in the session following this news. A strong positive reaction aligns with Boston Scientific’s strategy of adding differentiated structural heart technologies, as seen with the MiRus TAVR investment of $1.5 billion and an additional $3 billion option structure. Historically, solid earnings and approvals have at times produced robust gains but also occasional reversals. Investors would need to monitor future clinical milestones, integration execution and capital allocation discipline as enthusiasm around the SIEGEL valve’s 8 French delivery profile and pivotal trial progress evolves.

Key Figures

MiRus investment: $1.5 billion Equity stake: 34% Option payments: $3 billion +5 more

8 metrics

MiRus investment $1.5 billion Cash investment for ~34% equity stake in MiRus LLC

Equity stake 34% Approximate ownership interest in MiRus LLC

Option payments $3 billion Additional aggregate cash to acquire 100% of MiRus TAVR business

STAR pivotal trial size up to 1,025 patients Severe symptomatic aortic stenosis patients across surgical risk levels

Valve sizes 23 mm, 26 mm, 29 mm Available SIEGEL TAVR valve sizes evaluated in the STAR trial

Delivery sheath size 8 French Expandable sheath for all valve sizes

Sheath reduction 50% smaller Approximate reduction vs current commercially available TAVR delivery sheaths

Aortic valve narrowing severe, symptomatic Target patient population for SIEGEL TAVR system

Historical Context

5 past events · Latest: May 06 (Positive)

Pattern 5 events

Date	Event	Sentiment	24h Move	Catalyst
May 06	Peer earnings (PEN)	Positive	+1.0%	Penumbra Q1 2026 revenue growth and segment expansion ahead of BSX acquisition.
May 04	Conference & earnings call	Neutral	+0.6%	Planned participation in Bernstein conference and scheduling of Q2 2026 earnings call.
Apr 22	Q1 2026 earnings	Positive	+9.1%	Strong Q1 2026 net sales, EPS performance and multiple approvals/clinical wins.
Mar 30	Q1 call announcement	Neutral	-9.0%	Announcement of upcoming webcast to discuss Q1 2026 results.
Mar 30	FDA 510(k) clearance	Positive	-9.0%	FDA 510(k) clearance for Asurys Fluid Management System supporting endoscopic urology.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Pattern Detected

Recent BSX news often saw positive reactions to strong earnings, but a prior FDA clearance and a neutral conference-call notice both coincided with -9.02% moves, showing occasional negative reactions even on favorable updates.

Recent Company History

Over the last few months, Boston Scientific reported strong Q1 2026 net sales of $5.203 billion with a 9.09% next-day move, announced multiple earnings and conference call webcasts, and gained FDA 510(k) clearance for the Asurys Fluid Management System. A prior clearance and call notice both aligned with a -9.02% move, indicating that regulatory and communication events have sometimes faced selling pressure. Against this backdrop, the MiRus strategic investment adds another cardiology-focused growth initiative to that trajectory.

Key Terms

aortic stenosis, pivotal trial, porcine tissue, nitric oxide-coated, +3 more

7 terms

aortic stenosis medical

"patients with severe, symptomatic aortic stenosis considered to be at low, intermediate or high risk"

Aortic stenosis is a narrowing of the heart’s aortic valve that makes it harder for blood to leave the heart, similar to a door that won’t open fully or a garden hose with a pinched end. It matters to investors because the condition drives demand for diagnostic tests, medicines, surgical procedures and medical devices; changes in treatment options, clinical trial results or regulatory approvals can quickly affect the revenue and valuation of companies in the healthcare and medical-device sectors.

pivotal trial medical

"MiRus recently initiated the STAR pivotal trial that is evaluating the safety and effectiveness"

A pivotal trial is a key test of a new medicine or treatment to see if it works and is safe enough to be approved by health authorities. It's like a final exam for a new product, and passing it is essential for bringing the treatment to the public.

porcine tissue medical

"The SIEGEL TAVR valve is designed with leaflets made of dry porcine tissue and a nitric oxide-coated"

Porcine tissue is biological material taken from pigs that is processed for use in medical products such as implants, wound coverings, heart valve replacements or laboratory reagents. Investors watch porcine tissue because it affects a company’s product pipeline, regulatory approvals, manufacturing and supply chains, and customer acceptance—similar to how a food supplier’s business depends on reliable sources and public taste, changes in availability, safety checks or cultural concerns can change commercial prospects.

nitric oxide-coated medical

"leaflets made of dry porcine tissue and a nitric oxide-coated rhenium frame, which has a radial strength"

A nitric oxide-coated product is a medical device or material that has been covered with a layer designed to release small amounts of nitric oxide, a naturally occurring gas that can kill microbes and relax blood vessels. Think of it like a slow-release protective spray that helps prevent infections and improve how a device interacts with the body. Investors care because such coatings can increase a product's safety and clinical effectiveness, affect regulatory approval, extend patentable features, and potentially boost commercial value and market adoption.

radial strength medical

"a nitric oxide-coated rhenium frame, which has a radial strength greater than cobalt or titanium."

Radial strength is the measure of how well a tubular medical device (such as a stent or similar implant) resists being compressed inward by external pressure. It matters to investors because higher radial strength typically means the device will better hold open a blood vessel or passage under real-world forces, influencing clinical success, regulatory approval, manufacturing cost and market competitiveness — like a sturdy tent pole keeping a tent upright in wind.

investigational device regulatory

"The SIEGEL™ Balloon Expandable Transcatheter Aortic Valve Replacement (TAVR) system is an investigational device"

An investigational device is a medical instrument, implant, or tool that is being tested in humans but has not yet received full regulatory approval for general use. Think of it as a prototype on a monitored test drive: investors watch these devices closely because trial results, safety findings, and approval decisions determine whether the product can reach patients, generate revenue, or create regulatory and commercial risk.

aortic valve replacement medical

"Balloon Expandable Transcatheter Aortic Valve Replacement (TAVR) system is an investigational device"

Aortic valve replacement is a medical procedure that removes a damaged valve at the heart’s main outflow and puts in a new one so blood can flow properly, much like swapping a worn door hinge so the door opens smoothly. It matters to investors because demand, safety and cost for these replacements drive sales and profits for device makers, affect hospital revenue and influence regulatory and reimbursement decisions that shape a company’s growth.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Agreement includes exclusive option to acquire novel, balloon-expandable transcatheter aortic valve made with proprietary rhenium alloy

MARLBOROUGH, Mass., May 18, 2026 /PRNewswire/ -- Boston Scientific Corporation (NYSE: BSX) today announced it has invested $1.5 billion in return for an approximately 34% equity stake in MiRus LLC, a privately-held company developing and commercializing proprietary biomaterials, implants and procedural solutions for the treatment of cardiovascular and orthopedic diseases, including the SIEGEL™ Balloon Expandable Transcatheter Aortic Valve Replacement (TAVR) system. As part of the investment agreement, Boston Scientific also received an exclusive option to acquire the MiRus TAVR system, subject to additional payments and the completion of certain milestones. The SIEGEL technology is built on a proprietary rhenium alloy and is the first nickel-free, balloon-expandable TAVR valve intended to restore function and normal blood flow of severely narrowed aortic valves.

"The occurrence and recognition of aortic stenosis is growing rapidly and our investment in MiRus continues our pursuit to bring a differentiated TAVR system into our portfolio that we anticipate may improve outcomes for patients living with this life-threatening disease," said Lance Bates, executive vice president and president, Interventional Cardiology and Vascular Therapies, Boston Scientific. "Built upon years of research and proprietary technology, we believe the distinctive design and impressive early clinical results of the SIEGEL valve may set it apart from currently available technology, potentially providing physicians an advanced option to treat a wide array of patients."

The SIEGEL TAVR valve is designed with leaflets made of dry porcine tissue and a nitric oxide-coated rhenium frame, which has a radial strength greater than cobalt or titanium.¹ The open cell design of the frame is intended to eliminate foreshortening and aide precise placement in the heart. Uniquely, the valve is also pre-mounted directly onto the balloon and all sizes – 23 mm, 26 mm and 29 mm – can be precisely delivered through an 8 French expandable sheath, which is approximately 50% smaller² than current commercially available TAVR delivery sheaths and may minimize vascular injuries.

MiRus recently initiated the STAR pivotal trial that is evaluating the safety and effectiveness of the three sizes of the SIEGEL valve in up to 1,025 patients with severe, symptomatic aortic stenosis considered to be at low, intermediate or high risk for surgical complications. Last year, MiRus presented findings from an early feasibility study assessing the safety and performance of the device.

"The SIEGEL valve is a promising technology and has received enthusiastic feedback from physician investigators for its less invasive delivery, nickel-free construct, precise placement resulting from a lack of foreshortening and excellent hemodynamics," said Jay Yadav, M.D., founder and chief executive officer, MiRus. "This collaborative relationship with Boston Scientific alongside the exceptional capabilities of our Atlanta-based team can further accelerate our progress towards broad accessibility for patients and physicians for what we believe will be a transformational treatment."

The investment in MiRus is expected to be immaterial to adjusted earnings per share for Boston Scientific in 2026. Boston Scientific may exercise the option to acquire the MiRus TAVR business by making additional aggregate cash payments totaling $3 billion, at Boston Scientific's option following MiRus' achievement of certain clinical and regulatory milestones, that would result in 100% ownership of the TAVR business, subject to customary closing conditions. If Boston Scientific exercises the option, MiRus will have the right to receive additional payments based on net sales of the SIEGEL TAVR valve over a specified period and Boston Scientific will also have an exclusive option to acquire mitral and tricuspid replacement valve assets from MiRus for an additional payment. 

Caution: The SIEGEL™ Balloon Expandable Transcatheter Aortic Valve Replacement (TAVR) system is an investigational device, which is not yet approved for commercial distribution in any country.

^{1 Per ASTM standards specification
2 Edwards eSheath+ Introducer Set Instructions for Use (2023-08 10058349001 A)}

About Boston Scientific 
Boston Scientific transforms lives through innovative medical technologies that improve the health of patients around the world. As a global medical technology leader for more than 45 years, we advance science for life by providing a broad range of high-performance solutions that address unmet patient needs and reduce the cost of healthcare. Our portfolio of devices and therapies helps physicians diagnose and treat complex cardiovascular, respiratory, digestive, oncological, neurological and urological diseases and conditions. Learn more at www.bostonscientific.com and follow us on LinkedIn.

Cautionary Statement Regarding Forward-Looking Statements
This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Forward-looking statements may be identified by words like "anticipate," "expect," "project," "believe," "plan," "estimate," "intend" and similar words. These forward-looking statements are based on our beliefs, assumptions and estimates using information available to us at the time and are not intended to be guarantees of future events or performance. These forward-looking statements include, among other things, statements regarding the financial and business impact of the investment and the anticipated benefits of the investment, the exercise of the option and the timing thereof, business plans and strategy, clinical trials, product approvals and product performance and impact. If our underlying assumptions turn out to be incorrect, or if certain risks or uncertainties materialize, actual results could vary materially from the expectations and projections expressed or implied by our forward-looking statements. These factors, in some cases, have affected and in the future (together with other factors) could affect our ability to implement our business strategy and may cause actual results to differ materially from those contemplated by the forward-looking statements expressed in this press release. As a result, readers are cautioned not to place undue reliance on any of our forward-looking statements.

Factors that may cause such differences include, among other things:  economic conditions, including the impact of foreign currency fluctuations; future U.S. and global political, competitive, reimbursement and regulatory conditions, including changing trade and tariff policies; geopolitical events, conflicts and tensions; manufacturing, distribution and supply chain disruptions and cost increases; disruptions caused by cybersecurity events; disruptions caused by public health emergencies or extreme weather or other climate change-related events; labor shortages and increases in labor costs; variations in outcomes of ongoing and future clinical trials and market studies; market competition for our products; expected procedural volumes; new product introductions; demographic trends; the closing and integration of acquisitions, including our ability or determination to exercise the option and our ability to achieve the anticipated benefits of the investment or the option (if exercised); clinical trial results; business disruptions (including disruptions in relationships with employees, customers and suppliers) following the announcement and/or closing of the investment or the exercise of the option; intellectual property; litigation; financial market conditions; future business decisions made by us and our competitors; the execution and effect of our business strategy, including our cost-savings and growth initiatives; the conditions to the completion of the investment or the exercise of the option, including the receipt of any required regulatory approvals and clearances, may not be satisfied at all or in a timely manner; and the fact that the exercise of the option may not occur or may be delayed. New risks and uncertainties may arise from time to time and are difficult to predict. All of these factors are difficult or impossible to predict accurately and many of them are beyond our control. For a further list and description of these and other important risks and uncertainties that may affect our future operations, see Part I, Item 1A – Risk Factors in our most recent Annual Report on Form 10-K filed with the Securities and Exchange Commission, which we may update in Part II, Item 1A – Risk Factors in Quarterly Reports on Form 10-Q we have filed or will file hereafter. We disclaim any intention or obligation to publicly update or revise any forward-looking statements to reflect any change in our expectations or in events, conditions or circumstances on which those expectations may be based, or that may affect the likelihood that actual results will differ from those contained in the forward-looking statements, except as required by law. This cautionary statement is applicable to all forward-looking statements contained in this press release.

CONTACTS: 
Laura Aumann 
Media Relations 
(651) 582-4251
laura.aumann@bsci.com  

Lauren Tengler
Investor Relations
+1 (508) 683-4479
BSXInvestorRelations@bsci.com

View original content:https://www.prnewswire.com/news-releases/boston-scientific-announces-strategic-investment-in-mirus-llc-302774205.html

SOURCE Boston Scientific Corporation

FAQ

What did Boston Scientific (NYSE: BSX) announce about its investment in MiRus LLC on May 18, 2026?

Boston Scientific announced a $1.5 billion investment for about a 34% stake in MiRus. According to Boston Scientific, the deal includes an exclusive option to acquire the MiRus SIEGEL TAVR system, expanding its structural heart portfolio.

How much ownership in MiRus does Boston Scientific (BSX) receive from the $1.5 billion investment?

The $1.5 billion investment gives Boston Scientific an approximately 34% equity stake in MiRus. According to Boston Scientific, this strategic minority position aligns it with MiRus while preserving flexibility via an option to acquire the SIEGEL TAVR business later.

What is the SIEGEL TAVR system that Boston Scientific may acquire from MiRus?

The SIEGEL TAVR system is a balloon-expandable, nickel-free transcatheter aortic valve using a proprietary rhenium alloy. According to Boston Scientific, it features dry porcine tissue leaflets, an open-cell frame and delivery through an 8 French expandable sheath across three valve sizes.

What are the terms of Boston Scientific’s option to buy the MiRus TAVR business (BSX)?

Boston Scientific may acquire 100% of the MiRus TAVR business via additional cash payments totaling $3 billion. According to Boston Scientific, exercising the option depends on MiRus achieving specified clinical and regulatory milestones and is subject to customary closing conditions.

How will the MiRus investment affect Boston Scientific’s 2026 earnings per share?

Boston Scientific expects the MiRus investment to be immaterial to its adjusted earnings per share in 2026. According to Boston Scientific, the deal is structured as a long-term strategic move rather than an immediate earnings driver for that year.

What clinical trial is evaluating MiRus’s SIEGEL TAVR valve backed by Boston Scientific?

MiRus has begun the STAR pivotal trial to study the SIEGEL TAVR valve in up to 1,025 patients. According to Boston Scientific, the trial assesses safety and effectiveness in severe, symptomatic aortic stenosis patients across low, intermediate and high surgical risk categories.

Is the SIEGEL TAVR device in the Boston Scientific–MiRus deal already approved for use?

No, the SIEGEL balloon-expandable TAVR system is currently investigational and not approved for commercial use in any country. According to Boston Scientific, ongoing studies, including the STAR pivotal trial, will inform potential future regulatory submissions.