Boston Scientific Corporation (NYSE: BSX) announced a $1.5 billion investment for approximately 34% equity stake in MiRus LLC, a privately-held company developing cardiovascular and orthopedic medical devices. The investment includes an exclusive option to acquire MiRus's SIEGEL balloon-expandable transcatheter aortic valve replacement system.

The SIEGEL valve features a proprietary rhenium alloy frame and represents what the companies describe as the first nickel-free, balloon-expandable TAVR valve. The device uses dry porcine tissue leaflets and a nitric oxide-coated rhenium frame designed for treating severely narrowed aortic valves. All valve sizes can be delivered through an 8 French expandable sheath.

MiRus recently initiated the STAR pivotal trial evaluating the safety and effectiveness of three SIEGEL valve sizes in up to 1,025 patients with severe, symptomatic aortic stenosis at various surgical risk levels. The company presented findings from an early feasibility study last year.

Boston Scientific may exercise its option to acquire the MiRus TAVR business through additional cash payments totaling $3 billion, contingent on MiRus achieving certain clinical and regulatory milestones. This would result in 100% ownership of the TAVR business, subject to customary closing conditions. If exercised, MiRus would receive additional payments based on net sales over a specified period, and Boston Scientific would gain an exclusive option to acquire mitral and tricuspid replacement valve assets.

The investment is expected to have immaterial impact on Boston Scientific's adjusted earnings per share for 2026. The SIEGEL TAVR system remains an investigational device not yet approved for commercial distribution.