Leo Cancer Care Raises $65 Million Series D for Upright Radiotherapy Platform

Leo Cancer Care, a developer of radiotherapy and imaging systems that treat patients seated upright rather than lying down, has closed a $65 million Series D financing round, the company announced from Middleton, Wisconsin, and London on July 8.

The company described the round as oversubscribed. It was led by Silicon Valley investor Yu Galaxy and included new investors such as Eventide Asset Management, alongside existing backers. Leo did not disclose a valuation.

Where the money goes

Leo said the funding will scale manufacturing, accelerate commercial deployment and support continued clinical and product development across its platform, which spans proton therapy, photon therapy and imaging built around the same upright design. The company said its upright imaging system is FDA-cleared, with planned future applications across radiology in addition to treatment planning and delivery.

Its Marie proton therapy platform fixes the radiation beam in place and rotates the seated patient, rather than rotating a multi-tonne gantry around a patient lying down. Leo said that design allows a treatment room around five times smaller than a conventional gantry-based system, a comparison it said is based on actual facility drawings, so proton therapy can be installed inside existing radiotherapy vaults.

The company said Stanford Medicine delivered what Leo describes as the world's first compact upright proton therapy treatment on June 4, 2026, and that Dana-Farber Cancer Institute and McLaren Health Care are among the institutions bringing the upright platform into their programs.

Speaking to BioXconomy, CEO and co-founder Stephen Towe said the money would go to three priorities: manufacturing capacity to fill orders from cancer centers, commercial rollout in more than ten countries where Leo has or is pursuing regulatory clearances, and further clinical and product development.

An unnamed strategic partner

Alongside the financing, Leo said it has entered "a major strategic partnership with an international healthcare giant," with details to be announced separately in the coming weeks. Towe told BioXconomy that the round also brought "one of the world's most respected names in medical technology" onto the company's cap table. Neither company was named.

Towe also told the publication that Eventide "brings an outstanding track record of supporting innovative medtech companies as they transition from private financing into the public markets."

"For decades, the industry has tried to lower the cost of cancer care by making equipment cheaper and stripping out capability," Towe said in the release. "This financing lets us accelerate that platform strategy across proton, photon and imaging."

PR Yu, founder of Yu Galaxy and a long-time investor in the company, said in the release that Leo "is poised to revolutionize cancer treatment in more than ten countries, with many installations the first in their region or country."

Towe acknowledged in the BioXconomy interview that the company had "operated through a challenging global economic environment, and the journey has not always been straightforward." Leo's release includes a forward-looking statement noting that its plans for deployments, partnerships, manufacturing scale and international expansion are subject to risks and uncertainties.