For decades, vaccines have been seen as tools to prevent disease, protecting us from measles, flu, and even certain types of cancer like HPV. But what if a vaccine could treat cancer that already exists? IO Biotech is making significant strides under the leadership of Dr. Qasim Ahmad, Chief Medical Officer. At the 2025 ASCO (American Society of Clinical Oncology) Annual Meeting, he highlighted the company’s groundbreaking work on a new class of therapeutic cancer vaccines. These innovative vaccines are designed to train the immune system to directly combat tumors.
At the heart of this innovation is T-win®, a groundbreaking vaccine platform that could change how we treat cancer.
What Makes T-win® Vaccines Unique?
T-win® vaccines represent a first-in-class approach to cancer immunotherapy. Unlike existing immune-oncology treatments that block a single pathway or target one type of tumor antigen, T-win® vaccines have a dual-action mechanism:
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- They target immune-suppressive cells like Tregs (regulatory T cells) and TAMs (tumor-associated macrophages) within the tumor microenvironment (TME).
- They help reprogram the tumor’s environment, making it more inflammatory and supportive of an anti-tumor immune response.
This means T-win® vaccines not only help the immune system attack cancer cells directly, but they also disable the cancer’s defenses, allowing treatments to work more effectively.
How Do These Cancer Vaccines Work?
Here’s how the process works in simple terms:
- T-win® vaccines are made from peptides (small protein fragments) that match antigens commonly found on suppressive immune cells in tumors—like IDO1, PD-L1, and arginase-1.
- Once injected under the skin, the vaccine activates T cells that recognize and kill cells expressing those suppressive proteins.
- This activation helps kill tumor cells directly and weakens the suppressive shield tumors use to hide from the immune system.
“The vaccine activates and expands the T-cells… which engage and kill the tumor… It also modulates the tumor microenvironment, making it more pro-inflammatory,” Dr. Ahmad tells BlackDoctor.org.
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This strategy allows the immune system to see and respond to the cancer more effectively, improving the impact of both the vaccine and other immunotherapies.
Why “Off-the-Shelf” Matters
Unlike personalized cancer vaccines, which can take weeks to produce and are tailored to each patient’s specific tumor mutations, T-win® vaccines are off-the-shelf. They are designed to target common immune-suppressive antigens seen across many types of cancer.
This makes them:
- Faster to administer (available when patients need them).
- Applicable to more patients (not limited by rare mutations).
- Easier to combine with other therapies (due to their safety profile).
As Dr. Ahmad notes, “For the mRNA-based vaccines… you actually have to individualize their vaccine for the patient, which can take between two to six weeks. Our vaccine is available immediately.”
Where Are We Now? Clinical Progress
IO Biotech’s lead T-win® vaccine program is currently in Phase 3 clinical trials for advanced melanoma. Based on earlier data:
- Patients had an 80% response rate.
- 50% had complete responses.
- Progression-free survival reached 26 months—far beyond the 10–11 months typically seen with current therapies.
“These results were quite overwhelming,” Dr. Ahmad adds. “They led to breakthrough designation in 2021, and we are now running global trials in the U.S., Europe, Australia, and South Africa.”
Additional trials are underway for lung cancer, head and neck cancer, and bladder cancer, with future plans to expand into pancreatic, gastric, and genitourinary cancers.
What’s Next?
IO Biotech is also exploring combinations with checkpoint inhibitors and other therapies, believing that the broad utility of the T-win® platform can drive meaningful improvements in survival across several cancers.
“Once we get the Phase 3 results,” Dr. Ahmad explains, “we believe it will give us a boost to expand into other indications and combinations.”
Final Thoughts
The idea of using the immune system to fight cancer isn’t new, but doing so by modifying the entire tumor environment is. T-win® vaccines could become a powerful tool in transforming not just one kind of cancer, but many.
By turning the immune system into both a hunter and a healer, IO Biotech’s approach offers hope for faster, safer, and more effective treatment for people facing some of the most challenging cancers today.
