Middleton, Wisconsin, is not the place most people imagine when thinking about breakthroughs in cancer treatment, but that is where Leo Cancer Care just closed a $40 million round led by Catalio Capital Management. With Dr. Nicholas von Guionneau stepping in as a board observer, the company now has the fuel and strategic guidance to accelerate commercialization of its upright radiotherapy technology. This is not incremental progress; it is the kind of funding that transforms FDA clearance into real-world patient care.
Leo Cancer Care was co-founded in 2014 by Stephen Towe and Thomas “Rock” Mackie. Stephen Towe, now CEO, turned a personal tragedy into professional resolve. He lost his father to bowel cancer as a teenager, and that loss pushed him into a career defined by finding better ways to treat patients. After studying math and physics at Keele University and contributing to the Elekta Unity MRI-guided radiotherapy system, he co-founded Leo Cancer Care, where the patient, standing, not lying down, became the focal point.
Rock Mackie brings heavyweight credibility to this vision. With more than three decades in radiation therapy, he is best known for founding TomoTherapy and co-developing Pinnacle, the planning system that became a global standard. His career has been about turning science into scalable tools for clinicians, and Leo Cancer Care is the latest chapter in that playbook.
The company’s flagship systems, Marie® and Grace™, are more than products; they are reimaginings of how treatment should work. Marie, named for Marie Curie, applies upright positioning to particle therapies like proton and carbon ion. By rotating the patient instead of the beam, Marie eliminates gantries, cutting facility size and costs by up to 80 percent. Grace, named for Grace Hopper and unveiled at ASTRO 2025, takes the same upright approach into photon therapy. Both shrink the footprint of treatment, opening doors for hospitals and clinics that previously could not afford such infrastructure.
July 2025 marked a turning point when Marie® earned FDA 510(k) clearance. Suddenly, what had been an engineering vision became a clinical reality. McLaren Proton Therapy Center is preparing to treat the first upright patients, while UW Health has already validated the installation. These early adopters are proof points that upright therapy is not just a concept; it is becoming practice.
The funding will accelerate international expansion, with Singapore, Japan, and South Korea high on the list. The Singapore Economic Development Board already joined the investor group, underscoring the importance of Asia-Pacific growth. Meanwhile, partnerships with Mevion, RaySearch, Sumitomo Heavy Industries, and TibaRay give the company the kind of beam-agnostic flexibility that future-proofs its systems.
Leo Cancer Care is targeting a $10 billion radiotherapy market by stripping away the excess and focusing on precision, comfort, and accessibility. The company has raised $65.3 million to date, but the real story is not the money; it is the stance. Patients deserve to face treatment upright, and now the industry has no choice but to stand up and take notice.
