07 October 2025
From knock on the door to clinical trial
Whether I had a tube of Newcastle Disease Virus for him
A veterinarian and a pig farmer had experimented on themselves with an unconventional treatment. Against the odds, both continued to attend Casper van Eijck’s clinic. Their experience prompted the first study of a virus as a treatment for pancreatic cancer: the substance they had used was Newcastle disease virus (NDV).
Professor Ron Fouchier remembers Casper knocking on his door to ask whether he had a sample of NDV. "He wanted to use it to treat his patients. I had long been interested in genetically modifying viruses for human use and had advised the government on the subject. The idea had clear potential in oncology, but a treatment cannot simply be given to patients. Clinical research follows an extensive process to establish safety and effectiveness first." The laboratory did have the virus because Dr Bernadette van den Hoogen was using it as a control in another study. She says: "In 2010, Casper asked us to investigate NDV for viro-immunotherapy in people with pancreatic cancer. We began the work, and it has been a long journey. Fortunately, we are now close to completing that process."
Only way
Bernadette concentrated on the virus itself. "We grew the virus in the laboratory and tested whether it behaved as expected. We also had to show that the oncolytic virus could be used without causing disease outbreaks in poultry. Earlier studies and our own findings showed that NDV does not cause illness in humans. We have since demonstrated in the laboratory that it can kill both pancreatic cancer and brain tumour cells, and that it is safe for patients and the environment." Meanwhile, Ron and Casper searched for a company capable of manufacturing the virus. Suitable laboratories must meet exacting legal and safety standards. The first facility they found was fully booked, while others charged prohibitive fees or imposed unacceptable conditions, such as demanding all rights to the medicine. Building a dedicated laboratory became the only viable option.
Works really
The resulting ATMP laboratory at Erasmus MC is an important milestone. Ron says: "Having our own production facility is exceptional. Building and commissioning it takes time, but it is the only way forward. Before we can manufacture an oncolytic virus, every stage must be optimised and validated under different regulations. Only then can we move into clinical trials. I knew it would not be as simple as Casper imagined fifteen years ago, but I had not expected such complexity. We advance step by step, process by process." Bernadette adds: "We continue because progress never stops. In 2024, we reached another milestone. After showing in laboratory research that NDV works as an oncolytic virus, we also needed an animal model that could demonstrate the effect. We finally established the right model—a mouse with a pancreatic tumour—and the virus produced an antitumour response. It really works."
Hope happens
Because developing a new treatment takes so long, Ron and Bernadette are pursuing two routes in parallel. The team will soon produce test batches of a straightforward NDV variant, which should require relatively limited additional animal evidence before a clinical trial can begin. At the same time, researchers are comparing several modified variants that may prove even more effective against pancreatic cancer. Running the regulatory work alongside the laboratory research keeps progress as swift as rigorous safety standards allow. What began with Casper van Eijck knocking on a colleague’s door is now approaching production in Erasmus MC’s own laboratory—with the ultimate aim of giving patients a treatment that is both safe and effective.