Surgery and chemotherapy can treat pancreatic cancer, but cancer cells may remain in the body and cause the disease to return.
Researchers are exploring whether cancer vaccines could help the immune system identify and destroy these remaining cells, which could potentially lower the risk of recurrence.
A new study examined whether the experimental vaccine camupepimut could help reduce this risk in people who had already undergone surgery and chemotherapy.
The findings are published in Nature Medicine.
According to the American Cancer Society, pancreatic cancer makes up around 3% of cancer cases per year in the United States.
Pancreatic cancer is one of the most difficult cancers to treat, partly because it often does not have many early warning signs and is not often diagnosed until after it has already spread.
Read more:Migraine: Does HT cause longer-lasting attacks in postmenopause?
Pancreatic ductal adenocarcinoma (PDAC) is the most common form of pancreatic cancer. It has a high risk of recurrence, even after surgery and chemotherapy.
Mutations in the KRAS gene occur in around 90% of PDAC cases, which can cause cells to grow uncontrollably and contribute to cancer development.
With this in mind, researchers developed the vaccine camupepimut to target several common KRAS mutations. The vaccine delivers its components to the lymph nodes, where it helps immune cells recognize cancer cells with KRAS mutations.
The researchers described camupepimut as an “off-the-shelf” treatment that could potentially work for people with several KRAS mutations.
Unlike personalized cancer vaccines, which are developed based on an individual’s tumor, this approach could make the vaccine more widely available.
For the randomized phase 2 AMPLIFY-7P trial, the research team enrolled 144 participants with KRAS-mutated pancreatic cancer (stages 1 to 3). They had surgery and chemotherapy treatment before enrolling in the trial.
Read more:Does vitamin B12 really help prevent heart disease?
None of the participants showed signs of recurrence on imaging tests when they entered the trial.
The researchers divided participants into two groups:
The team focused on disease-free survival, or how long they lived without their cancer returning or dying. They also examined immune responses and treatment safety.
The researchers found that the vaccine triggered a strong immune response in nearly everyone in the vaccine group.
The vaccine activated T cells that target KRAS mutations in nearly 99% of the test group. The vaccine also increased T-cell activity by more than ninefold in 82.2% of those evaluated.
Despite these strong immune responses, the vaccine did not meet the study’s primary endpoint for disease-free survival.
Read more:Breast cancer: GLP-1 use may substantially lower risk
The median disease-free survival was 23.8 months in the vaccine group compared with 21.2 months in the observation group.
At 6 months, 75.7% of the vaccine group remained disease-free, compared with 61.7% of the control group.
Although this difference suggested a possible early benefit, it did not reach statistical significance. The researchers also did not find a statistically significant improvement in disease-free survival over the full follow-up period.
After conducting further analyses, the researchers believe that certain people might benefit more from the vaccine.
For example, participants who had no detectable circulating tumor DNA (ctDNA) at the start of the trial appeared to experience better disease-free survival after vaccination. Detectable ctDNA can indicate that cancer cells remain in the body after treatment.
Read more:Autism and menopause: Autistic women have more severe symptoms
The team also observed an association between stronger T-cell responses and longer disease-free survival.
The researchers reported that the vaccine was generally well-tolerated, with no treatment-related deaths or adverse events that caused any of the participants to discontinue treatment.
The team plans to investigate camupepimut further in a phase 3 trial, potentially using additional booster doses and combining the vaccine with other treatments.
Anton Bilchik, MD, PhD, surgical oncologist, chief of medicine and Director of the Gastrointestinal and Hepatobiliary Program at Providence Saint John’s Cancer Institute, who was not involved in the study, told Medical News Today that the findings are “extremely important” despite the lack of a statistically significant survival benefit.
“It shows that a very resistant cancer such as pancreatic cancer is capable of responding to a vaccine provided the patient develops a strong immune response,” Bilchik explained.
He noted that the study’s small size and limited vaccination period may have influenced the results.
Read more:Lung cancer: Can a new blood test warn of recurrence early on?
“We should therefore interpret these results with optimism recognizing that more studies need to be done to evaluate the benefit in different subsets of patients and in determining the survival benefit when the vaccine is given for a longer period,” Bilchik told us.
Jason Williams, MD, founder and director of interventional oncology and immunotherapy at Williams Cancer Institute, who was also not involved in the study, explained that activating the immune system is only part of the challenge.
“Seeing the cancer is the first step,” Williams said. “Clearing it is another.”
He suggested that combining the vaccine with other treatments could help overcome pancreatic cancer’s ability to suppress the immune system.
“The immune system needs more than one signal: It has to see the target, and the tumor has to stop shutting it down. A larger randomized trial will have to show patients stay cancer-free longer.”
– Jason Williams, MD
