Vaccine targeting pancreatic cancer shows promise in new study of clinical trial

When a routine scan led to Barbara Brigham’s pancreatic cancer diagnosis in 2020, all she could think about was how she wanted more time. Her husband had just passed away. She loved her local library job. Her three children were still growing their own families. 

She turned to her care team at Memorial Sloan Kettering Cancer Center to learn about her options. Brigham had first come to the cancer center when she was diagnosed with a small, non-cancerous cyst on her pancreas. Every year, she had a scan to make sure there were no new cysts. It was that annual scan that found the early-stage pancreatic cancer.  

Brigham and her youngest son went to Sloan-Kettering the next day to meet with Dr. Vinod Balachandran, a surgical oncologist who specializes in pancreatic cancer. While laying out her options to fight the cancer, he mentioned that he was running a clinical trial that he believed she would be the “perfect candidate” for. 

The trial would combine standard surgery and chemotherapy treatments — which are the standard of care for pancreatic cancer — with a customized mRNA vaccine. Each vaccine would be designed based on the patient’s individual tumor. The idea was that the vaccines could hopefully help the body’s immune system attack the cancer, Balachandran told CBS News. 

“I looked at my son, and my son said, ‘Absolutely.’ So we decided to do that,” Brigham said. “The prognosis was not good when I was diagnosed. You know you’re going to have a limited amount of time. I just wanted to extend that time.” 

Helping an immune system recognize cancer  

The inspiration for the clinical trial came from the small handful of long-term pancreatic survivors, Balachandran said. Only about 10% of people diagnosed with pancreatic cancer survive for more than five years. 

About a decade ago, Balachandran and other researchers turned their attention to these “long-term” survivors. Multiple studies found that the long-term survivors’ immune systems generated “spontaneous immune response” to the cancer, meaning the immune system could recognize that the cancer was a threat and react accordingly. Typically, it’s “challenging” to teach the immune system to recognize cancer, said Balachandran, because “the immune system is hardwired not to recognize our own body.” 

“This led to this question of, ‘If this is what is happening in the best case scenario, could we then replicate the success in other pancreatic cancer patients?’ Namely, could we teach other patients’ immune systems to recognize their cancers in a very similar way as to what is happening naturally in the long-term survivors?” Balachandran said. 

The phase 1 clinical trial looked at 16 patients with early-stage pancreatic cancer like Brigham’s. To be eligible for the trial, a patient’s cancer had to only be in the pancreas and be removable with surgery. Those conditions occur in just between 20% and 25% of pancreatic cancer patients, Balachandran said, and mirrored the conditions of most long-term survivors. During surgery, a patient’s tumor was removed, then sent to Sloan-Kettering’s research partners at the German biotechnology company BioNTech. From the tumor, BioNTech would make the vaccine, which would be given to the patient alongside several weeks of immunotherapy and chemotherapy. 

The vaccine targeted mutations created by pancreatic cancer. As cancer cells rapidly divide in the body, they accumulate genetic errors, Balachandran said. Those errors could serve as “red flags to the immune system,” he said, so it became a matter of alerting the immune system to those cells and teaching it to recognize them. 

Sparking “strong immune responses” 

Of the 16 patients included in the trial, eight had “strong immune responses,” Balachandran said. The difference seemed to hinge on what kind of surgery they had to remove their pancreatic cancer: People who had their spleen removed as part of their treatment did not generate a strong immune response, Balachandran said, likely because of the important role the organ plays in immune function. 

Earlier data published by Balachandran showed that of the eight people who had strong immune responses, none of them had their cancer recur 18 months after treatment. On average, people whose early-stage pancreatic cancer is treated with chemotherapy and surgery see their cancer recur in a year or less.

Now, new research published in Nature looked at the same patients 3.2 years after their treatment. The follow-ups found that only two of the eight patients who had a strong immune response saw their cancer return. 

Meanwhile, seven of the eight non-responding patients had their cancers return within that 3.2-year window, Balachandran said.

While the data seems promising, Balachandran cautioned that it’s “still hard to attribute causality” to the vaccine, especially because of the trial’s small size. 

Dr. Suneel Kamath, a gastrointestinal oncologist at the Cleveland Clinic who was not involved with the trial, pointed out that the survival rate of the patients in the trial is similar to the survival rate of people who have early-stage pancreatic cancer treated with surgery and chemotherapy. 

“This was a nice kind of proof-of-concept study to show that we can make a vaccine for this disease, and it really does actually create an immune response, and an immune response that lasts,” Kamath said. “That’s a very nice backbone to build off of.” 

Another, larger clinical trial is now underway, Balachandran said. This randomized trial will only focus on early-stage pancreatic cancer patients with intact spleens, to confirm what role that organ plays in the process, he said. It will also help confirm if there is a link between the vaccines and better outcomes for pancreatic cancer patients. 

mRNA vaccines as cancer treatment 

Many other researchers are focusing on how mRNA vaccines could be used to treat cancer. Such research was underway well before the coronavirus pandemic thrust mRNA vaccination into the spotlight, said Kamath, who is working with the company Moderna on a different mRNA vaccine trial looking at pancreatic and gastric cancer. 

Part of what makes mRNA vaccines suitable for cancer treatment is how easily they can be customized, Kamath said. Balachandran said that it took about nine weeks for a vaccine to be made for each patient in the clinical trial. That included international shipping on both sides, he said. 

“The beauty of mRNA vaccines, as we saw with COVID development, is they’re very fast to make. It easy to generate. Once you found a new target, it’s very quick to make a vaccine for that particular target,” Kamath explained. “It’s really exciting, because when we talk about curing cancer, it’s not really a single monolithic disease. There are probably hundreds of different targets for every cancer type. And so the ability to make vaccines against a lot of those different targets very quickly is really powerful.” 

Part of that research is learning which cancers are better candidates for mRNA vaccines to be used as part of the treatment, Kamath said. Things like melanoma, which causes a lot of mutations in the body, are easier to direct the immune system against. Kidney and lung cancers are other promising options, he said. 

Something like pancreatic cancer, which has fewer mutations, is more difficult, but has been the subject of previous research. Balachandran said part of his goal in looking at pancreatic cancer was to see if mRNA vaccines could make a difference “among the most challenging cancers in oncology.” 

“Hopefully this can provide some important lessons and clues and how we can do this in other cancer types,” Balachandran said. 

“Such a wondrous thing” 

For Brigham, participating in the clinical trial gave her what she wanted: More time with her family and loved ones — more than four years after she was diagnosed with pancreatic cancer. On average, for people whose pancreatic cancer is caught “before the tumor grows much or spreads,” survival time is about three to three and a half years, according to Johns Hopkins. 

 In the past few months, Brigham celebrated several milestones. Her youngest son welcomed his first child — her eighth grandchild — in late 2024, and she recently joined her extended family for her brother’s 60th wedding anniversary. 

Brigham has not had any recurrences since she took part in the trial. The removal of part of her pancreas did make her diabetic, because the organ produces insulin, but she says it’s manageable. 

“The trial was such a wondrous thing,” Brigham said. “It has just given me such a renewal in my life. Sometimes it’s a little difficult, but it’s worth it, absolutely worth it.”