According to a study jointly led by researchers at Memorial Sloan Kettering Cancer Center (MSK), a new vaccine is showing promising initial results as a potential standard treatment for certain patients with pancreatic or colorectal cancer. The vaccine targets tumors with mutations in the KRAS gene, a driver in many cancers.
This cancer vaccine is different from another type of pancreatic cancer vaccine that is custom-made for each patient using messenger RNA (mRNA). Both are therapeutic vaccines administered after surgery to prevent or delay cancer recurrence in high-risk patients.
„Having an off-the-shelf vaccine would make treatment for a larger number of patients easier, faster, and more cost-effective,“ said medical oncologist and pancreatic cancer specialist Eileen O’Reilly, MD, who co-led the study and is one of the corresponding authors of the published study in Nature Medicine. „This gives hope to people with pancreatic and colorectal cancer who have run out of effective treatments upon recurrence of their disease.“
Dr. O’Reilly is co-author of the Nature Medicine study, along with Shubham Pant, MD, from MD Anderson Cancer Center, and Christopher M. Haqq, MD, PhD, from Elicio Therapeutics.
Results of clinical trials on the KRAS vaccine for pancreatic and colorectal cancer
The Phase 1 study involved 25 patients with pancreatic or colorectal cancer that had specific KRAS mutations and were at high risk of cancer recurrence after surgery. The results showed that this vaccine is safe and appears to stimulate the patient’s immune system to create cancer-fighting cells:
- 84% of patients showed the desired immune response, meaning immune T-cells targeting KRAS-mutated cancer cells were activated and increased in number.
- Also, in 84% of patients, a marker for remaining cancer cells –; the amount of tumor DNA circulating in the blood –; was reduced. Tumor DNA was absent in 24% of patients.
- Most importantly, patients with a higher T-cell response also experienced a longer period without disease recurrence, known as recurrence-free survival.
„For patients whose immune systems appeared to respond to the vaccine, there was a delayed recurrence of cancer compared to patients who did not respond to the vaccine. We can build on such early clinical effects,“ said Eileen O’Reilly, MD, medical oncologist and pancreatic cancer specialist.
Differences between off-the-shelf vaccines against KRAS mutations and personalized mRNA vaccines
Another approach to activate immune cells has been advanced by surgical oncologist Vinod Balachandran, MD. He is investigating whether a personalized mRNA vaccine using proteins from a patient’s pancreatic tumors alerts the immune system to the foreign nature of the cancer cells. This way, the mRNA vaccine trains the body to protect against cancer cells. This vaccine is currently being tested in a Phase 2 research study at MSK and other institutions.
Personalized vaccines –; although promising –; also have challenges. They take a long time to manufacture and are expensive. In contrast, an off-the-shelf standard vaccine could be administered to patients with minimal delay and would be more cost-effective to produce.
„These results are exciting because they show that we may have more than one way to activate immune cells to fight pancreatic cancer,“ said Dr. O’Reilly.
Memorial Sloan Kettering Cancer Center
Hose., et al. (2024). Lymph node–targeted, mKRAS-specific amphiphilic vaccine in pancreatic and colorectal cancer: the Phase 1 study AMPLIFY-201. Nature Medicine. doi.org/10.1038/s41591-023-02760-3.