Naji Gehchan: Welcome to SpreadLove in Organizations, the healthcare leadership podcast where we explore leadership with purpose.
This episode is in partnership with the Termeer Institute, a nonprofit organization working to vibrantly connect and empower the world of healthcare innovators until every patient has a cure.
I’m Naji Gehchan, your host, joined today by Hanne Callewaert, CEO and co-founder of AstriVax Therapeutics.
Hanne has over 20 years of life sciences industry expertise. Previously, she was Chief Operating Officer at the publicly listed biotech company Oxurion, where she led multidisciplinary teams. She also gained extensive vaccine development expertise through several roles at GSK Vaccines.
Hanne started her career at De Clercq & Partners as a patent attorney trainee. She holds a Master’s degree in Biomedical Sciences, a Master’s degree in Intellectual Property Law, and a PhD in Medical Sciences from KU Leuven.
Hanne, it’s great to have you with me today on my show.
Hanne Callewaert: Thank you so much, Naji. The pleasure is all mine.
Naji Gehchan: Let’s start where we always do. I’d love to learn more about your personal story and what made you co-found AstriVax Therapeutics.
Hanne Callewaert: Okay. Well, let me go a bit back in time and talk more about vaccines. After my PhD, and after a short sidestep into patent law, I joined GSK Vaccines. I spent 10 years of my career there, which was an incredible experience.
That’s really where I started to appreciate the impact of vaccines on public health. Vaccines are not just protecting individuals; they really transform population health. They prevent disease, reduce transmission, and create herd immunity. I think vaccines are one of the most powerful tools in global health ever. You can really compare their impact to clean drinking water or wearing a seatbelt.
At GSK, I intentionally worked on different types of vaccines: viral vaccines, bacterial vaccines, and maternal immunization protection. After 10 years, I had the chance to move into biotech, but I still remember telling my colleagues that I’d probably come back to vaccines at the end of my career because the impact is just so significant.
After spending five years in ophthalmology and oncology, I met one of the co-founders, Professor Johan Neyts. To make a long story short, we kept talking about the fantastic technology he and Kai Dallmeier had developed. We started looking at spinning it out and building a business plan around it.
The technology is a platform technology. You could call it the next generation after mRNA vaccines, maybe 10 years after Moderna and BioNTech. That’s how it all started. We collaborated, spoke with many investors, secured seed financing, spun out the technology, and started AstriVax Therapeutics in 2022.
Naji Gehchan: Oh wow. Before we go deeper into the platform and building a company from scratch, I want to ask you something more personal.
You came from the patent world, then worked in big pharma, fell in love with vaccines, and now you’re an entrepreneur building a startup from scratch. What has connected all those chapters for you personally? What created this love for vaccines?
Hanne Callewaert: I think the connecting factor is that I’m an extremely curious person. I really want to learn every single day and expand my knowledge.
Since I was a child, I’ve been fascinated by medical sciences and understanding how everything works, but also by the impact you can have. The connection between my education and all the work I’ve done is really about asking: How can we make lives better? How can we prevent diseases? How can we treat them?
Even the patent side, for me, was about understanding how you valorize innovation in a sustainable way. I wanted to understand how scientific discoveries could actually become products that reach patients.
The reason I didn’t stay in patents is that I’m much more of an all-rounder. I like understanding many things broadly rather than becoming an ultra-specialized expert. With all my respect for patent attorneys, they are deep experts in an incredibly difficult field. I realized I wouldn’t be happiest staying there professionally.
Naji Gehchan: Tell me more about what you do now with AstriVax. I think most people know the term mRNA vaccine because of COVID, but many don’t really understand what it means. Could you explain vaccines in simple terms and what makes your platform different?
Hanne Callewaert: Absolutely.
A vaccine, in very simple terms, is a biological molecule that you give to a human being in order to activate the immune system. You’re essentially training the immune system to recognize a pathogen. Once the immune system recognizes that pathogen, it can clear it and prevent disease.
In therapeutic settings, it can also train the immune system to kill infected cells.
There are many different kinds of vaccines. You have live viral vaccines, where the virus is attenuated but still resembles the pathogen. You have dead viruses, protein-based vaccines, and what I call template vaccines, which are newer genetic vaccines like mRNA, self-amplifying RNA, or DNA vaccines.
These vaccines contain genetic instructions. Once injected, the body reads those instructions and produces the biologically active component itself. It’s like giving the body a book that it reads and translates into action.
mRNA vaccines were the front-runners in this area, especially Moderna and BioNTech.
What we developed is a DNA-based system. It’s plasmid DNA that encodes the sequence for a live attenuated virus. Live attenuated vaccines are incredibly effective, but historically they’ve been difficult to manufacture and less stable. We wanted to bring that power into a more modern DNA platform.
The additional advantage is that we kept space on the plasmid to insert an additional gene of interest. That makes it a true platform technology. You can insert different antigens and tailor immune responses.
When injected, the system produces a live attenuated viral vector alongside the antigen of choice, creating a potent immune response. We call this our launched immunotherapy technology.
Naji Gehchan: I love it. What are the major differences you expect between your DNA-based platform and mRNA technologies?
Hanne Callewaert: I strongly believe every vaccine technology has pros and cons. It’s important to understand where each one is best deployed.
Our technology has several advantages. First, DNA is relatively simple to manufacture. Compared to mRNA, the process is much simpler and involves fewer manufacturing steps.
DNA is also much more stable. You can expose it to elevated temperatures and still maintain functionality. We all remember during the pandemic how challenging cold-chain logistics were for mRNA vaccines.
Biologically, because we induce a live attenuated virus response, we can generate long-lasting immune responses, especially strong T-cell responses. We may even achieve that with a single dose.
This is why we want to use the platform therapeutically, not just preventively. That’s a novel concept in vaccinology: treating already infected individuals with therapeutic vaccines.
For that, you need T-cell responses capable of killing infected cells.
Naji Gehchan: That’s fascinating. So you’re not only looking at prevention, but also boosting immune responses in already infected patients.
Hanne Callewaert: Exactly.
Our lead candidate focuses on treating patients infected with human papillomavirus, HPV, to help clear the virus. We see this as a major unmet need.
Preventive HPV vaccines are fantastic, but many people remain unvaccinated for different reasons. HPV is sexually transmitted, and while many people naturally clear the virus, a significant number remain persistently infected.
Certain strains, like HPV-16 and HPV-18, are strongly associated with cervical cancer. More than 90% of cervical cancers are caused by HPV infection.
Our hypothesis is simple: if prevention didn’t happen, then treatment should occur before cancer develops.
Naji Gehchan: That makes complete sense. How did HPV become the mission focus for the company specifically?
Hanne Callewaert: We looked at the capabilities of the platform and generated early clinical data showing that the technology is well tolerated and capable of inducing strong T-cell responses.
We evaluated several viruses, but HPV stood out because of its direct correlation with cancer. It also gives us measurable viral endpoints in clinical trials, allowing us to track efficacy through viral clearance and regression of precancerous lesions.
Naji Gehchan: I want to ask you something broader around vaccines.
Vaccines obviously saved millions of lives during the pandemic, but they also became highly debated. Now, when people hear RNA, DNA, or genetic technologies, there are a lot of myths and fears.
What would you say to people listening who may still have concerns about vaccines or genetically engineered therapies?
Hanne Callewaert: It’s a very relevant question because it’s on many people’s minds.
Every medicine that reaches the market undergoes extremely rigorous evaluation. Vaccines especially are evaluated carefully because they are often administered preventively to healthy populations.
The benefit-risk profile is always critical.
One thing that makes vaccines harder for some people to accept is that the benefit is often collective rather than immediately individual. With treatments, people feel the direct benefit because they are already sick. Vaccines are different because they protect populations through herd immunity.
I actually had a personal experience with this.
At one point, I had to travel to The Gambia while working at GSK, so I received the yellow fever vaccine, Stamaril. Shortly afterward, I developed vaccine-induced meningitis and encephalitis, an ultra-rare event.
It took me weeks to recover and months to feel fully normal again.
But despite that experience, I never lost my faith in vaccines. Vaccines remain one of the most powerful tools we have to protect populations from devastating diseases.
One challenge today is that, because vaccines have been so successful, many people no longer remember how devastating diseases like polio once were.
Naji Gehchan: That’s such an important point. Diseases like polio caused paralysis and death, and vaccines changed the world.
Hanne Callewaert: Exactly. Without vaccines, we would still live in fear of diseases like polio.
Viruses are often underestimated. People think of a runny nose or fever, but viruses can kill and can also cause long-term consequences like cancer.
That’s what we work on with HPV.
Naji Gehchan: You started AstriVax in 2022, right after the pandemic. What has the journey been like building a vaccine company through all the highs and lows?
Hanne Callewaert: It’s been an incredible journey.
We started with a very small group and expanded to around 30 people. We moved very quickly into the clinic, thanks to an exceptional team with experience from pharma and academia.
For me, building a company is really about building the team. Cultural fit matters enormously. Every hire was evaluated not only for capability, but also for alignment with our values.
We’ve moved fast, achieved milestones, generated data, and now we’re fundraising again.
Yes, vaccine sentiment has become cyclical. People quickly forget the consequences of pandemics and viral diseases. But I believe we will continue convincing the right people who understand the importance of this work.
Naji Gehchan: When you think about the next 10 years in infectious disease, vaccines, and biotech, what gives you the most hope?
Hanne Callewaert: For me, it’s clearly the rise of therapeutic vaccines.
Preventive vaccines are already highly established. Of course, there’s still room for optimization, but now we’re entering a new era where vaccines can treat infections, not just prevent them.
That’s where I think the next decade will focus.
Naji Gehchan: And what about cancer vaccines? There’s been huge excitement around them.
Hanne Callewaert: What we focus on are cancers driven by viruses. Ideally, we want to intercept disease before cancer fully develops.
That doesn’t exclude eventually moving into cancer itself, but our immediate focus is persistent viral infection and precancerous disease.
Cancer vaccines outside viral oncology remain a very challenging space. There have been some successes, but also many failures. Still, advances in machine learning and epitope screening may improve outcomes over time.
Naji Gehchan: I’m going to give you a few words, and I’d love your first reaction to each.
First: leadership.
Hanne Callewaert: Leadership, for me, is growing into it every day.
I believe strongly in leading by example, both professionally and personally. I’m also a mother of four children, and honestly, that’s probably my first leadership role. Children are brutally honest and give immediate feedback.
I try to bring that same transparency into the company. I believe in genuine leadership, no hidden agendas, and helping people grow.
Even as a small company, we try to expose people to different disciplines so they leave having learned more than when they joined.
Leadership is continuous learning. You’re never a finished product.
Naji Gehchan: What about team?
Hanne Callewaert: Team is everything.
You can have a fantastic technology, but if the team doesn’t work well together, it won’t matter.
We’ve been high-performing because people understand the bigger picture. I set a high bar for myself and for others, but it’s also important to celebrate together and stay transparent.
People need to understand how their work connects to the larger mission.
Naji Gehchan: The next word is Termeer Institute.
Hanne Callewaert: I’m incredibly grateful to have been part of the 2024 cohort.
I wasn’t very familiar with it initially, but fellow CEOs encouraged me to apply. It became much more meaningful than I expected.
We still stay in touch weekly through a very active WhatsApp group. We share ideas, concerns, celebrations, all in a very safe environment.
Being a CEO can be an incredibly lonely role. Having that community makes it easier.
Naji Gehchan: And the final one: Spread Love in Organizations.
Hanne Callewaert: One of our core company values is caring.
That means caring for patients, but also caring for each other. If you want to be high-performing and bring treatments to patients, you need to genuinely care about the people around you.
That’s how strong organizations are built.
Of course, we’re all still learning. I’m sure I’ve made many mistakes, but I hope I’ve done more good than harm.
Naji Gehchan: I’m sure you have. Any final word of wisdom for leaders around the world?
Hanne Callewaert: It’s still tough out there.
As a leader, you need resilience because there are many setbacks, and often very few people you can openly talk to.
I think leaders need to connect more and be honest about how hard life can sometimes be as a CEO, but also how rewarding it can be.
It’s important to care for each other because if the leader isn’t doing well, eventually the organization won’t either.
This is not a sprint. It’s a marathon. I’m still learning every day how to sustain myself through it.
Naji Gehchan: Thank you so much. This was a wonderful discussion.
Congratulations on everything you’ve built and everything AstriVax is doing. Hopefully, your platform will help millions of patients affected by HPV.
Thank you again for being with me today, Hanne.
Hanne Callewaert: Thank you so much, Naji. This was a very nice conversation. Thanks for having me.
Naji Gehchan: Thanks for listening to the show! For more episodes, make sure to subscribe to Spreadloveio.com or wherever you listen to your podcasts. Let’s inspire change together and make a positive impact in healthcare, one story at a time.
Follow us on LinkedIn and connect with us on spreadloveio.com. We’re eager to hear your thoughts and feedback. Most importantly, spread love in your organizations and spread the word around you to inspire others and amplify this movement, our world so desperately needs