Peptide-Based Cancer Vaccines May Offer Effective Protection Against Aggressive Tumors

New research in immunotherapy is exploring vaccines to treat cancer, whether preventative or reactive against current tumors.

Ferry Ossendorp, PhD, talks to Pharmacy Times at the 2022 International Cancer Immunotherapy Conference about innovative new research being done in the field of peptide-based vaccines to treat cancer and individualize this treatment.

Q: How did your previous studies guide you to look at cancer vaccines as a treatment?

Ferry Ossendorp, PhD: Basically, I started working on this topic in the 90s, already a long time ago, briefly a century, because I know my first observations that if you know the antigen of a certain tumor, and you will vaccinate a mouse, for instance, that you can really protect the mouse against this very aggressive tumor. That was, for me, really an eye opener. Only a small peptides with only one epitope can do the job, basically. So, that gave me the insight that should be possible (sufficient about cancer), that you may be able to feed them with immunotherapy.

Q: Can you describe the role of peptide-based cancer vaccines as adjuvant treatment?

Ossendorp, PhD: T cells and T lymphocytes are the cells that can really recognize cancer cells. They can recognize really small peptides that are presented on the cell surface of the tumor cells. And they can even show, let's say, on the outside what is wrong in the tumor cell. So small mutations, which are inside tumor cells can be presented from the outside. If you notice peptides, then you can use them to vaccinate and induce the right T cells, which are really tumor-specific; with the vaccine, for instance, that should be possible and that's what we're working on.

So peptides are really the small parts of proteins that are processed and presented on the outside of a tumor cell. And therefore, we're working on these peptides and we can make them synthetically. If you know the right sequence, you can make them synthetically and define certain vaccines or certain drugs to make the immune system really specific for the cancer cells.

Q: How does this vaccine impact the tumor immune environment?

Ossendorp, PhD: So you have to discriminate, basically, between prophylactic vaccine, where you fractionate an individual before having cancer, or therapeutic vaccines. And that is, of course, more difficult.

So in a prophylactic setting, you still have a healthy immune system. You can vaccinate and then increase your immunity against a certain type of cancer. That can be done, for instance, with HPV. So HPV induced cervical cancer and the prophylactic vaccines can be used to protect girls women for for this type of oncogenic viruses.

In a therapeutic setting, it's more difficult. There, you already have an existing tumor. Then you have to elevate, let's say, existing immunity or induce novel immunity to try to treat the tumor. And that is now what I'm working on. And of course, the tumor is really creating a sort of suppressive environment and therefore, this comes all together. Now every activity and these new immunotherapies are in the clinic now. Vaccination combinations with this type of immunotherapy become a reality in my perspective.