XS Innovations bringing a new standard to dialysis care
XS Innovations is tackling a major challenge for people with end-stage kidney disease: keeping their blood vessel access open for dialysis. Most patients need a special connection between an artery and a vein in their arm, called an arteriovenous fistula (AVF), to ensure enough blood flows during treatment. However, this connection often causes problems like heart strain, vessel narrowing, or occlusions. These issues lead to serious health risks, repeated hospitalizations, increased healthcare costs, and a heavy burden on patients’ well- being.
To address this, XS Innovations is developing an implantable valve that allows healthcare professionals to open and close the AVF as needed—so the fistula can be closed when dialysis isn’t taking place.
By reducing the time, the AVF stays open, the team expects fewer complications, leading to lower costs, better quality of life, and improved outcomes for dialysis patients.
Prof. dr. Joris Rotmans, internist-nephrologist at the LUMC and co-founder of XS Innovations, managed to set up a multidisciplinary research collaboration to develop his idea of a dynamic valve for the prevention of AVF complications. Years of effort and promising results led to a venture with a diverse and experienced team, €1,8 million raised and more in vivo data on the way. Together with XS Innovation’s CEO and co-founder Toon Stilma, Joris shares the founding story.
J O R I S :
“I’ve worked on AVFs for over twenty years, starting with my PhD. Initially, I studied why AVFs fail—why vessels get blocked. Later, I shifted to improving outcomes. Together with Koen van der Bogt, vascular surgeon at LUMC and HMC, we explored new therapies like cell therapy, pharmacological interventions and tissue engineered blood vessels. During the years to follow, I realized that the continuous high and turbulent blood flow is the main factor responsible for complications such as narrowing or aneurysm formation in the AVF.
We teamed up with TU Delft researchers to create a device limiting these negative effects. Together with Tim Horeman, associate professor and Nick White, PhD student and R&D engineer at XS Innovations, and we conceived a valve that opens and closes via a magnetic system. Once we had a prototype, I felt this could be the solution. Though unproven clinically, it was the best idea so far. That’s when I decided to commit fully—not just publish but develop a product with a strong team. To give perspective: the first design was drafted around 2017. It feels fast, but we’re eight years in now.”
T O O N :
“I first encountered the technology during its university development. Nick was finishing his PhD, and the team secured an NWO Take-off 1 grant to explore commercial feasibility. With that grant, we assessed whether it made sense to create a company. At the time, I led Roland Berger Tenzing, a network supporting entrepreneurs on niche topics. We had experience in nephrology collaborations and were eager to support Joris’ project. The technology impressed me: an urgent medical need, few alternatives, and an elegant, straightforward invention.”
J O R I S :
“I had launched a spin-off before but without Take-off funding. This grant gave us crucial business support. Through a colleague, I connected with Roland Berger, who brought valuable kidney-tech expertise. Toon’s help was very useful. Together with Alexandra Kleijn senior consultant at Roland Berger, we managed to create a detailed business which formed the basis for the next steps towards the foundation of XS Innovations.
T O O N :
“A turning point came when we truly believed in forming a company with a strong team. The Take-off work tested team dynamics and confirmed we had fun, ambitious people with solid academic backgrounds and networks.”
J O R I S :
“That pivotal moment was fueled by encouraging experimental results showing the concept worked, alongside recognition that the device needed optimization. We realized to apply it clinically, we needed a robust, professionally developed product with a specialized manufacturer. This was product development, not science. Traditional academic grants no longer fit, so we decided to continue as a spin-off.”
T O O N :
“We had a good idea, team, and draft business plan. Funding was limited early on, but small grants—including a TTT voucher—helped. Patent filings and university negotiations took time but went smoothly with mutual trust. Step by step, we moved toward company formation. A major challenge was converting an academic prototype to an FDA/MDR-compliant device. This meant redoing drawings, specs, and supplier arrangements under strict rules. It felt like double work but was essential. Academic curiosity sometimes clashes with regulatory rigidity—step one, two, three, then back to one if something fails.”
J O R I S :
“Although regulatory documentation is crucial, it had not been a primary focus of mine as a scientist. Fortunately, other team members possess the necessary expertise and experience to handle this aspect effectively. Early support from the RegMed XB/DCVA voucher was very helpful to take the first steps with professionalizing the quality management.”
T O O N :
“Financing early-stage development was another significant challenge. Even essential expenses like legal fees for license agreement reviews were difficult to cover without external support. That’s where the TTT vouchers played a vital role—they not only prevented us from having to pay out of pocket but also added important credibility when approaching other potential funders. The TTT program was especially valuable because it bridged the gap between the academic world, which primarily relies on grants and subsidies, and the commercial landscape dominated by private investments. For young companies like ours, TTT provided a crucial stepping stone that helped us transition smoothly from research to market readiness.
There are interested investors, but those who act quickly are rare. Jaap de Bruin from F1RST fund helped us organize a syndicate of early-stage investors including Graduate Entrepreneur Fund, LEH, Delft Enterprises, UNIIQ, TTT Innovation Industries, and of course F1RST, raising €1.1 million. This funding allowed us to establish the company, hire key staff, and secure a 12–18 month runway—giving us breathing room so we didn’t have to constantly chase new capital. It wasn’t easy, but thanks to the team’s efforts, the expertise of Joris and our CMO Koen van der Bogt, and the relative simplicity of the technology, we managed to convince investors.
Still, we encountered some disconnects between our development stage and investor expectations—for example, being asked for tax declarations before the legal entity even existed, which didn’t make sense.”
J O R I S :
“Adjusting to investor conversations was a big shift for me. Academics focus on science; investors want business models, market potential, and exit strategies. Terms like ‘value inflection points’ and ‘investor readiness’ were new. Medical questions often come through investors rather than specialists, so we must explain complex biology clearly. We feel we’re moving quickly toward the clinic. Although the company started just over a year ago, progress has been remarkable. Balancing my roles as CSO, university researcher, and company lead is challenging—time management is a constant struggle as pressure to move faster is always there.”
T O O N :
“We’re preparing the next investment round, by which time we’ll show the company is fully operational, advancing toward FDA approval, with key test results expected this summer.
After summer, robust preclinical data from cadaver and sheep studies will confirm the device’s safety, functionality, and positive impact on heart and vessels. We plan to start the First in Human study in late 2026, aiming for 10–12 implantations over a year to demonstrate clinical effectiveness. For this phase, we seek EUR 6.5 million, partly government grants and loans, partly from our existing investors and other VCs. We hope to secure funding from existing TTT syndicate investors, while also engaging other VCs. In summary, with a validated prototype, we are now seeking financing to make the critical step toward clinical translation.”
XS Innovations was supported by a voucher from the RegMed XB/DCVA TTT program and received funding from F1RST, partner in the TTT program. Thanks to the funds made available by the Ministry of Economic Affairs, the team of XS Innovations could make major steps in company formation and product development.
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