Historically, pancreatic cancer is one of the deadliest malignancies. New data from the six-year follow-up of a clinical trial using a personalized mRNA vaccine offers a measure of hope. Professor Irit Ben Aharon, a world-renowned oncologist at Rambam Health Care Campus, comments on these findings.
Often diagnosed at an advanced stage, pancreatic cancer has a five-year survival rate of less than 13%. No routine screening test exists for early detection, and only about 20% of patients are eligible for surgery—a prerequisite for participation in this type of clinical trial.
Rather than attacking disease directly, messenger RNA (mRNA) consists of small pieces of genetic code that instruct the body to produce specific proteins, helping the immune system recognize and fight illness. Its applications are being studied across a range of fields, including genetic disorders, heart disease, and cancers such as pancreatic cancer.
Initial results from a small early-phase clinical trial of 16 patients led by Dr. Vinod Balachandran, Director of the Cancer Immunology Center at Memorial Sloan Kettering Cancer Center (MSK) in New York, were published in Nature on February 19, 2025.
Three-year Follow-up
At a median follow-up of 3.2 years, eight of the patients developed a strong immune response and showed significantly lower relapse rates while the other half did not respond as well. More recently, researchers presented six-year follow-up data at the annual meeting of the American Association for Cancer Research in San Diego. The gap between the two groups is striking: seven of the eight responders remain alive, compared to only two of the eight non-responders, with a median survival of 3.4 years. The long-term data suggest that the immune response has remained active for six years, an encouraging finding from this small study.
Referring to the study, prominent oncologist, Professor Irit Ben Aharon, Director of the Joseph Fishman Oncology Center at Rambam, emphasizes that timing is critical. After surgeons remove the primary tumor and patients complete standard chemotherapy, a key window opens for adjuvant treatment—in this case, the mRNA vaccine. Targeting microscopic residual disease at this stage may reduce recurrence.
“The recurrence rate after surgery is very high. By targeting microscopic disease, researchers aim to eliminate the residual cancer cells that may lead to relapse,” says Ben Aharon. “Equally important is the mechanism itself: each vaccine is tailored to the unique profile of the patient’s tumor, targeting its specific antigens rather than applying a one-size-fits-all approach.”
The vaccine does not eliminate existing tumors; instead, it targets cancer cells that remain after surgery. Clinicians send the removed tumor for genetic analysis and then design a personalized vaccine based on up to 20 unique mutations. These mutations produce neoantigens—foreign proteins that immune cells can recognize as threats. Patients then receive the vaccine alongside standard chemotherapy.
The 2025 Nature study found that vaccine-induced immune cells can be long-lasting, with an average lifespan of about 7.7 years and some persisting for more than a decade. Follow-up data suggest that stronger immune responses are linked to longer survival. However, cancer recurrence in some patients underscores that, while promising, the vaccine is not a complete solution.
What Does the Future Hold?
“Despite its promise, significant work remains,” Ben Aharon adds. “The study involved a small cohort of 16 patients, with only about half responding strongly. Larger, more advanced trials must validate these findings and identify which patients are most likely to benefit—particularly those who develop a robust immune response without recurrence. The results inspire optimism but require careful interpretation.”
Professor Ben Aharon notes that researchers still need to better understand how mRNA vaccines work in this setting. However, she points out that the approach offers real hope—that pancreatic cancer may one day be treated by training the patient’s own immune system.
Based on a Hebrew article that first appeared on YNet.
