Boston Scientific $BSX disclosed Monday a $1.5 billion investment in privately held MiRus LLC, securing roughly a 34% ownership stake along with an exclusive option to take over MiRus' heart valve operations.
The deal gives Boston Scientific a 34% stake in MiRus and an option to buy its TAVR business for an additional $3 billion
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Boston Scientific $BSX disclosed Monday a $1.5 billion investment in privately held MiRus LLC, securing roughly a 34% ownership stake along with an exclusive option to take over MiRus' heart valve operations.
The deal centers on MiRus' SIEGEL balloon-expandable transcatheter aortic valve replacement (TAVR) system, an experimental device used to treat severe aortic stenosis — a condition in which the heart's aortic valve narrows and restricts blood flow. The SIEGEL valve is not yet approved for commercial sale in any country, the company said.
If certain clinical and regulatory goals are met, Boston Scientific can buy MiRus' TAVR business for an additional $3 billion in cash. If the acquisition goes through, MiRus will receive ongoing milestone payments based on future SIEGEL valve sales for a set period. Boston Scientific would also have the exclusive right to buy MiRus' mitral and tricuspid replacement valve products, with the price to be decided separately.
Unlike competing balloon-expandable TAVR products, the SIEGEL valve uses a rhenium alloy frame and contains no nickel — a design distinction the company highlighted as a key differentiator, the company said. The valve's frame is coated with nitric oxide and features an open-cell design intended to allow precise placement. All three available sizes — 23 mm, 26 mm, and 29 mm — can be delivered through an 8 French expandable sheath, which Boston Scientific said is about 50% smaller than current commercially available TAVR delivery sheaths.
MiRus has started the STAR pivotal trial to test the safety and effectiveness of the SIEGEL valve in up to 1,025 patients with severe, symptomatic aortic stenosis. The trial will include patients at low, intermediate, and high surgical risk.
The deal marks Boston Scientific's return to the balloon-expandable TAVR market, which it exited in May last year, according to Reuters.
"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," Lance Bates, executive vice president and president of Interventional Cardiology and Vascular Therapies at Boston Scientific, said in a statement.
Jay Yadav, MD, founder and CEO of MiRus, called the relationship with Boston Scientific a means to "further accelerate our progress towards broad accessibility for patients and physicians," in a statement.
The company said its adjusted earnings per share for 2026 are not expected to be meaningfully affected by the investment.
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