Researchers discuss promising new study on personalized vaccines for pancreatic cancer

A team of researchers at Memorial Sloan Kettering Cancer Centre in New York published a paper in Nature this week describing promising results in a small clinical trial testing the use of personalized vaccines to treat pancreatic cancer. The story made headlines around the world, including an in-depth feature in The New York Times. 

The paper described how novel, personalized vaccines created by the team provoked an immune response in one-half of the 16 patients who participated in the study. These patients, who had their tumours surgically resected prior to the vaccine doses and received immunotherapy after it, showed no relapse of their cancer after 18 months—a promising result for an aggressive cancer with a very low, five-year survival rate. 

We spoke to two MOHCCN experts, Dr. Daniel Renouf, a clinician-scientist and medical oncologist at BC Cancer specializing in precision oncology for pancreatic cancer, and Dr. Nicole Beauchemin, a cancer survivor, retired cancer researcher based in Montreal and co-chair of our Patient Working Group, to better understand this important study and its potential for impact on the science of precision medicine and the lives of cancer patients. Both are excited by the findings. 

How it works 

Drs. Renouf and Beauchemin say that one of the most fascinating developments presented in this study are the vaccines themselves, which were created using novel mRNA technology like that used in some COVID vaccines. 

Interestingly, these vaccines were personalized to each study participant, meaning that the genetic data from each patient’s tumour was used to develop the "neoantigens" (mRNAs encoding novel parts of proteins from the surface of tumour cells), which were used in the vaccine.  

Once inside the patient’s body, this personalized mRNA generated fragments of proteins like those on the surface of their tumour cells. These proteins were considered foreign to the patient’s immune system, which in response produced specific cells – in this case T cells – that were primed to recognize, attack and destroy anything resembling those proteins. 

“Just as with a vaccine against micro-organisms and viruses, the patient's immune system was ready to eliminate any cancer cells that showed up with those proteins, essentially halting cancer recurrence,” explains Dr. Beauchemin.  

Importantly, the study showed that these personalized vaccines could be created quickly (under six weeks) by building on the mRNA/liquid nanoparticle approach used in many millions of SARS-CoV-2 vaccines, an approach that the researchers and vaccine manufacturers believe has the potential to be applied to other cancers which have multiple mutations. 

Exciting results; but more information needed 

The fact that the findings demonstrated some patients had an expansion of T-cell populations, and those patients had a longer median, recurrence-free survival is promising, according to Dr. Renouf.  

As a clinician-scientist who treats patients with pancreatic cancer daily, he knows that one of the major goals in pancreatic cancer research is to see if new treatments – such as immunotherapy – could be made available for patients diagnosed with this deadly disease. 

"Pancreatic cancer is generally considered an “immune cold” tumour, meaning the immune system does not react to it, so the fact that this group has found a way to activate T cells in some patients which could then be treated with immunotherapy is very exciting,” he says. 

However, Dr. Renouf believes that there is still a lot of work to be done before knowing what real-world impact this finding could have. 

“While the data presented is quite intriguing, the main limitation of this study is that the sample size is very small – only 16 patients were treated with the vaccine – and follow up was relatively short,” he says. “There also needs to be a better understanding of the characteristics of the patients that developed a T-cell expansion post vaccine/immunotherapy, and those who didn’t, so we can actually determine who will benefit from this treatment and who won’t.” 

However, he remains optimistic about the prospect this strategy may bring. “The fact that a larger randomized trial of this strategy is planned means that we will hopefully have good data showing how big of an impact these vaccines may have.” 

Dr. Beauchemin concurs.   

“There needs to be more studies of course, in different types of aggressive cancers, in different stages of cancers, in different ethnic and genetic backgrounds,” she says. “But to see the results of this clinical trial with patients living well beyond two years instils hope for future successful therapies, where patients can lead long productive lives.” 

From her own experience as a cancer survivor and researcher, she knows that these kinds of developments are important steppingstones towards improving survival and quality of life for patients, who will benefit from personalized precision medicine strategies such as this. 

“This vaccine is an amazing example of personalized precision oncology and treatment,” says Dr. Beauchemin. “Precision oncology is the full recognition that no two humans are perfectly alike and that even with conventional chemotherapy treatments, the patient's response can be quite different. Designing new approaches and treatments that take into consideration individual patient's tumour specificity leads to more effective treatments and patient survival.”