Personalized mRNA vaccine shows lasting immune response in pancreatic cancer trial

The encouraging news is not that pancreatic cancer has been solved. It is that a custom-made mRNA vaccine helped some patients build an immune response that still looked durable nearly four years later, a rare signal in one of the deadliest cancers. In a phase 1 trial at Memorial Sloan Kettering Cancer Center, 16 people with resected pancreatic ductal adenocarcinoma received autogene cevumeran, also known as BNT122 or RO7198457, after surgery and standard treatment. The vaccine was personalized to each patient’s tumor mutational profile and paired with atezolizumab and modified FOLFIRINOX chemotherapy. In the updated Nature report, 8 of the 16 patients mounted vaccine-induced T-cell responses, and those responders had longer recurrence-free survival than non-responders, whose median recurrence-free survival was 13.4 months.

The biology behind the result is what makes researchers cautious and hopeful at the same time. In responders, vaccine-induced CD8+ T-cell clones were estimated to live an average of 7.7 years, with some projected to persist for roughly a century, and the study found that these immune cells could still be detected years after vaccination. Memorial Sloan Kettering reported that tumor-specific immune cells persisted in some patients for nearly four years, while the National Cancer Institute said 6 of the 16 patients were still cancer-free, some more than three years after surgery. The earlier phase 1 data also showed the treatment was safe, with no serious side effects reported.

That matters because pancreatic cancer remains brutally difficult to treat. Fewer than 13% of people diagnosed with the disease live more than five years, and around 90% of cases are found only after the cancer has already advanced. The trial was designed around a central problem in pancreatic oncology: these tumors often offer the immune system relatively few obvious targets, making durable immune control hard to achieve. The vaccine’s appeal is that it tries to turn each patient’s own cancer mutations into a tailor-made target list.

The next test is much larger and much slower. A phase 2 randomized trial is already recruiting and is expected to enroll about 260 patients in the United States, Europe and Asia Pacific, comparing autogene cevumeran plus atezolizumab and mFOLFIRINOX against mFOLFIRINOX alone. ClinicalTrials.gov lists the study as recruiting, with a last update posted March 12, 2026 and an estimated completion date of January 1, 2031. That timetable is a reminder that even the strongest early signal still has to survive years of testing before it can become routine care.