From Virtual Company to International Superdeal
Funding new biotechnological developments in cancer research is often a challenge. At the Rotterdam-based startup Sairopa, things went more smoothly. This allowed the development process for two anti-cancer antibodies, which show promise as potential immunotherapy drugs, to start in a more targeted manner. These antibodies work through various mechanisms aimed at supporting the immune system in fighting cancer.
“It all started with my brother,” says Gurvinder Chahal. “Dharminder has been active in biotech investments for about twenty years and saw a unique opportunity here. He collaborates extensively with Van Herk Investments, and that was also the case with this company. Van Herk and Dharminder together invested the first €17.5 million in 2021 to set up Sairopa. We chose to focus on developing two specific antibodies, and that was the start of Sairopa.”
Family business
At its core, Sairopa is a family business, but the Chahal brothers quickly received support from people familiar with the field. “The funny thing is that the antibodies were originally developed in the Netherlands. After mergers and acquisitions, they ended up in the United States. We reached out to the Dutch scientists who had been involved to help us further. This created a small team of experts. In the early days, we were mainly a virtual company, meeting online every Tuesday evening to discuss how we could quickly and efficiently bring the selected antibodies to patients.”
Different mechanisms within the immune system
Sairopa develops new cancer treatments by activating the patient’s immune system. “The antibody ADU-1805 helps the immune system recognize cancer cells more effectively, enabling a more targeted attack. The other antibody, ADU-1604, enhances the immune system’s activity itself, so it can clear cancer cells more efficiently,” explains Gurvinder.
An Expensive Business
Money is crucial in the biotech industry. In 2022, Sairopa managed to secure an option with the American company Exelixis, which contributed to continuing the clinical programs. “Eventually, we faced a deadline: €17.5 million is a lot of money, but in the expensive biotech business, you can go through it in two years, especially if you want to conduct clinical trials. So we had to make a choice: do we stop one of the programs, raise new funds from Van Herk, or find a Pharma or Biotech partner to pursue it together? We chose the latter, and I’m quite proud of that.”
Making impact
Chahal is particularly proud of the product Sairopa is developing: “The idea that a lab-developed molecule is safe, can be combined with existing drugs, and could contribute to longer survival or recovery in oncology patients is very special for us as a Rotterdam-based company. When we finalized the collaboration with Exelixis, we only had one FTE; now our team consists of ten to twelve permanent employees, supported by a similar number of consultants, particularly in pharmacology and the preclinical research phase.”
Home City
Despite its success, the company is still headquartered in Rotterdam. A conscious choice? Chahal: “Our investors are from Rotterdam. And we are from Rotterdam. We also wanted a location with a bit of a community feel. That’s why we went to the CIC, near Central Station.”
Sairopa now also has a second office in Oss. “Many of our clinical staff come from there, so it’s practical,” Chahal explains. “But the corporate office remains in Rotterdam. That has always been our home city.”
Life Science & Health Ecosystem
Rotterdam has a vibrant life science & health ecosystem. Sairopa benefits from this, although new partnerships are primarily sought abroad. “Within the Rotterdam ecosystem, the network is especially valuable. You learn from each other and see how other companies get things done in the Netherlands. We are ultimately still a Dutch BV. We are part of the Life Sciences & Health network of Rotterdam Square, a member of Hollandbio, and other organizations that help with challenges in the Dutch biotech sector. For example, we are currently in talks with the government about the innovation box and how it could help Sairopa advance innovative research.”
“Additionally, the network is crucial for finding employees. The biotech world is very small; everyone knows each other. Most of the people who work with us come from other biotech companies. So, you need a good reputation and treat your people well, so they want to work for you. If you have certain expertise, you can work anywhere in this sector. There is just a lot of work.”
Plans for the future
Chahal looks forward to the next steps. “In the short term, we will start larger trials, testing our molecule with one of the antibodies on three or four tumor types. That is the crucial part: what we have conceptualized on paper could soon really be used to improve the survival chances of cancer patients. How amazing would that be!”
Date: December 16, 2025
