Our investment in CollimateHealth
Radiotherapy is one of medicine's great workhorses. Around half of all cancer patients receive it at some point, and for many it is central to their treatment. But it runs into a stubborn ceiling. In the hardest cases, doctors can't turn the dose up to the level they'd like without also damaging the healthy tissue around the tumour. When a tumour sits next to the brain, the spine, or other critical anatomy, even a small amount of collateral damage can be life-altering. So the dose gets capped - and with it, the odds of controlling the cancer.
That ceiling is exactly what CollimateHealth is built to break.
The core idea sounds almost too simple. Instead of delivering radiation as a uniform sheet of dose, you deliver it as a fine striped pattern: many hair-thin, high-intensity X-ray beams separated by low-dose gaps. Healthy tissue, it turns out, tolerates this remarkably well, while tumours are still strongly damaged. This is microbeam radiotherapy (MRT), and decades of research suggest it can widen the "therapeutic window" - the gap between a dose that helps and a dose that harms - far beyond what conventional radiotherapy can reach. It also does more than kill tumour cells directly: it appears to wake up the immune system and reshape the blood vessels feeding the tumour, which makes it a natural partner for immunotherapy and chemotherapy.
There has been one very large catch. Producing microbeams at the intensities needed has, until now, required a synchrotron - a particle accelerator that can stretch the length of a football field. Extraordinary science, but not something you can wheel into a hospital. For decades that has kept MRT stranded in a handful of research facilities: compelling in the lab and in animal studies, but effectively out of reach for patients.
CollimateHealth's leap is to recreate synchrotron-grade microbeams from a compact source - a specialised X-ray tube paired with a precision collimator that carves the beam into stripes - small enough to fit in a standard treatment room. Put simply, they are shrinking a football field down to the size of a hospital room. If it holds up at clinical scale, that turns a national-facility experiment into a device a cancer centre can actually install and use.
What excites us most is where this could lead in combination. Because microbeams appear to prime the immune system and disrupt a tumour's blood supply, they pair naturally with treatments that attack cancer along those same lines. One of those treatments is being developed by another company in our portfolio, CimCure, whose cancer vaccines train the body's own immune system to destroy the network of blood vessels that tumours depend on. A radiation platform that makes tumours more visible to the immune system, working alongside a vaccine that turns that immune system against the tumour's vasculature - the logic of combining approaches like these is a large part of what makes this field so exciting to us right now.
None of this is easy, and the hard engineering and clinical validation still lie ahead. What ultimately convinced us was the team. CollimateHealth grew out of the Technical University of Munich and the Institute of Cancer Research in London, founded by three people who have lived this problem for years: Hans Maria Heÿn (CEO), Dr. Johanna Winter (CTO), who spent six years building the core technology, and Prof. Stefan Bartzsch (CSO), who has worked on microbeam therapy for over a decade. They are clear-eyed about the risks, disciplined about their milestones, and genuinely thrilled by the work that lies ahead.
We're proud to back Hans, Johanna, Stefan and the CollimateHealth team, alongside our friends at VP Venture Partners, HTGF, XISTA Science Ventures, and caesar. Taking one of oncology's most promising ideas and finally making it fit inside a hospital is exactly the kind of leap we started Positron to support.
