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A Systemic Approach to Oncolytic Viruses to Treat Solid Tumors and Metastases

KaliVir Immunotherapeutics’s CEO Dr Helena Chaye discusses how the biotech is developing a systemically delivered oncolytic virus therapy with the goal of serving patients with metastatic disease.

March 11, 2025
A Systemic Approach to Oncolytic Viruses to Treat Solid Tumors and Metastases

What is the work you’re leading at KaliVir as CEO?

Our goal is to develop viral treatments that can reach and eliminate cancer cells in the body, bringing us closer to a cure for all cancer patients.

We are developing systemically deliverable oncolytic virus immunotherapies that harness viruses to infect and destroy cancer cells. Our approach combines the viruses' natural cancer-killing abilities with novel mechanisms that stimulate anti-tumor immunity and reshape the tumor environment, maximizing effectiveness across all tumor types. 


Where do you see this having the greatest patient benefit? 

We see particularly promising opportunities for patients with metastatic disease who need systemic treatment options, those who have developed resistance to existing immunotherapies and patients with "cold" tumors that traditionally don't respond well to immunotherapy. The ability to deliver our therapy intravenously makes it especially valuable for patients with hard-to-reach tumors or multiple tumor sites. 

We're particularly excited about the potential impact on aggressive solid tumors where current treatment options are limited. Initially, we're focusing on solid tumors. Ultimately, we envision this as part of a comprehensive treatment strategy that could benefit patients at various stages of their cancer journey, from first-line therapy to those who need additional options after other treatments have failed.

"Our approach combines the viruses' natural cancer-killing abilities with novel mechanisms that stimulate anti-tumor immunity and reshape the tumor environment."


What gap in treatment does this approach mitigate? 

First, most existing therapies using oncolytic viruses must be injected directly into tumors, which severely restricts their use to accessible tumors and excludes many patients with metastatic disease. Our approach enables intravenous delivery, reaching tumors throughout the body. 

Second, while traditional oncolytic viruses often lose effectiveness due to the body's natural antiviral immune response, we've engineered our platform to maintain its therapeutic impact even in the presence of antiviral immunity.

Third, many existing viral therapies carry limited therapeutic payloads, reducing their cancer-fighting potential. We've enhanced our viruses with multiple potent mechanisms to attack cancer cells and stimulate anti-tumor immunity.

Finally, current therapies often lack precise tumor targeting, leading to reduced effectiveness. Our platform incorporates specific targeting mechanisms to help our viruses home in on cancer cells while sparing healthy tissue.

"We envision this as part of a comprehensive treatment strategy that could benefit patients at various stages of their cancer journey, from first-line therapy to those who need additional options after other treatments have failed." 


Oncolytic viruses are typically injected intratumorally; how are you achieving a systemic administration? 

We’ve overcome this limitation by using viral strains that have already been shown in the clinic that they can be delivered systemically - vaccinia virus' natural ability to travel through the bloodstream. 

We've enhanced this capability by engineering our viruses to express specific chemokine receptors, guiding the virus to tumors through B-cell mediated targeting. This allows us to deliver our therapy through standard IV administration and for repeat treatment in the presence of neutralizing antibodies, making it possible to reach metastatic tumors throughout the body.


How else are you improving upon existing oncolytic virus immunotherapies?

Most require direct injection into tumors, struggle to spread throughout the tumor and can be neutralized by the body's natural antiviral defenses.   

We addressed this limitation head-on by utilizing vaccinia virus natural ability to infect B-cells. Our viruses encode a chemokine receptor that is expressed on the surface of infected B-cells such that they now carry the virus to cancer cells expressing the correlating ligand to the chemokine receptor. 

Additional proprietary modifications to the vaccinia virus backbone include extracellular degrading enzymes to enhance spread of virus within the tumor mass, redirecting anti-virus immune response to anti-tumor immune response. KaliVir also has IP for novel therapeutic payloads to validated targets. This lets us develop targeted treatments that can effectively penetrate tumors while maintaining their therapeutic impact even in the presence of antiviral immunity.


If your work in systemic oncolytic viral delivery is successful, what could the impact be for the broader IO community? 

By proving that systemically delivered viral therapies can effectively target tumors throughout the body, we could open new treatment possibilities for patients with metastatic disease who currently have limited options. In addition, our work could provide crucial insights into how to better engage the immune system against cancer. Our platform's ability to both directly attack cancer cells and stimulate anti-tumor immunity could offer valuable lessons about combining different therapeutic approaches. This could inform the development of more effective combination treatments across the immuno-oncology field.

Perhaps most importantly, success in our approach could establish a new paradigm for cancer treatment – one where we can reliably deliver powerful immunotherapies throughout the body while maintaining their therapeutic impact. This could encourage broader innovation in systemic delivery methods for other types of cancer therapies, ultimately expanding the toolkit we have to fight cancer.


What are current challenges for your role as CEO, for the stage that KaliVir is currently in, and the larger environment-level challenges? 

As a growing clinical stage company, we're navigating several interconnected challenges. From an organizational perspective, our key focus is maintaining momentum in our development programs while strategically expanding our team and capabilities. This means making careful decisions about resource allocation and ensuring we have the right expertise at the right time.

We're seeing increased interest in novel cancer therapeutics, which creates both opportunities and the need to differentiate ourselves in a competitive space. We're addressing these challenges by continuing to strengthen our strong relationships with strategic partners, maintaining clear communication with our stakeholders and staying focused on our core mission of developing transformative cancer treatments. 

Importantly, we're remaining adaptable while keeping our long-term goals in sight. The field of oncolytic virus immunotherapy is rapidly evolving, and we're positioning ourselves to not just respond to changes but to help shape the future of cancer treatment.


What made you passionate about entering this field and keeps you passionate?

I wanted to bridge the gap between scientific discovery and real-world impact, which drew me to law school to study intellectual property. While I initially thought patent law would keep me connected to innovation without being at the bench, my time in law school actually revealed my true calling in biotech business development.

I am excited by the prospect of developing a best-in-class oncolytic vaccine that can be manipulated to switch from being a pathogen to something that we can use to treat patients and then treat cancer.


What was a piece of career advice that helped you during your career that you would pass on to young people, particularly young women, entering careers in science? 

Don’t be afraid to take on new challenges, even if you have never done it before. Don’t be afraid to “fail.” There are learnings to be had with each experience – whether failure or success.  If your path that you have laid out takes detours, do not get discouraged. Find mentors and listen. 


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