Eradicating Cancer: How Personalized Vaccines are Changing Cancer Treatment

This blog post simplifies an article posted by the Yale School of Medicine, and explores the technologies mentioned in the article.

Earlier this year in February a clinical trial was led by David Braun, MD, PhD, to explore the usage of Personalized Cancer Vaccines (PCVs) in patients with advanced kidney cancer. Let’s explore what PCVs are and how they work:

What is a Personalized Cancer Vaccine?

Rather than being a vaccine used for prevention, this is a therapeutic vaccine, which means it is used for patients who already have cancer. This vaccine trains the patient’s immune system to target leftover cancer cells using neoantigens as an identifier. 

What makes it “personalized” is that the vaccine is custom-built based on the patient’s unique tumor DNA.

How do they work?

To understand PCVs, we first need to define neoantigens: Neoantigens are identifier proteins found on the surface of some cancer cells that result from mutations in the tumor’s DNA. These proteins are “new” to the body—hence the prefix “neo”—and do not exist on healthy cells, making them ideal targets for the immune system.

To train the immune system, the mutation is sequenced and through this, a prediction of the neoantigen structure is made. This is administered to the patient using the personalized cancer vaccine.

Ok, back to the clinical trials at Yale. In this study, PCVs were used for nine patients with Stage III or Stage IV kidney cancer. For seven out of the nine patients, the vaccine worked. Their immune systems were able to find and fight off the remaining cancer cells, leaving them cancer free for at least three years.

Why does this all matter?

Current immunotherapy drugs for kidney cancer help activate the immune system, but they don’t give it a clear target. This sometimes leads to the immune system attacking healthy body cells, a disease called autoimmunity. Pair this with chemotherapy, a treatment designed to attack all fast dividing cells, not just cancer cells. That includes hair follicle cells, the cells of the gut lining, bone marrow cells, the list goes on. 

PCVs aim to direct the immune system precisely toward the cancer, using unique markers only found in the tumor.

Although this was a small, phase I trial, the success lays the groundwork for larger studies. It signals the potential for PCVs to become part of future cancer treatment plans.