Phase II mRNA Vaccine Trial Opens

The highly reported-on mRNA pancreatic cancer vaccine has opened its phase II clinical trial, as of August 2023.

The trial is initially recruiting patients through Memorial Sloan Kettering Cancer Center locations in the greater New York area. However, in the coming months it will be open at 80 locations around the world.

Vaccines using messenger RNA (mRNA) have been widely lauded for their ability to reduce hospitalizations and deaths from COVID in the last few years. But researchers have been developing mRNA vaccines in the lab for many years. Now this approach is beginning to show some exciting promise for pancreatic cancer, one of the toughest cancers to treat, with very few effective treatment options.

Promising Phase I Results

The results of the phase I study, published in Nature in May, showed that half of the 29 pancreatic cancer patients who received a personalized mRNA cancer vaccine after surgery did not have a recurrence of the tumor a year and a half later. The trial focused on patients with early-stage pancreatic cancer, all of whom were white. Clearly, the results needed to be replicated in larger studies with a more diverse group of patients.

In the phase I study, researchers simply wanted to know if the mRNA vaccine could stimulate a patient’s immune system to fight their cancer. The answer was “yes,” explains Memorial Sloan Kettering surgeon–scientist Vinod Balachandran, M.D., who led the phase I trial in collaboration with Genentech, a member of the Roche Group, and BioNTech, an immunotherapy company. Now, in this much larger study, researchers want to determine if the mRNA vaccine works better than current standard treatment.

The mRNA vaccines are custom-made for each person. They use proteins in the pancreatic tumors, called neoantigens, to alert the immune system that the cancer cells are foreign. In this way, the mRNA vaccine trains the body to protect itself against cancer cells.

Details About the New Trial

The new phase II trial is investigating whether this therapeutic vaccine reduces the risk of pancreatic cancer returning after the tumor is removed surgically. The study will enroll approximately 260 patients who have not yet had surgery or other treatment (such as chemotherapy, immunotherapy, or radiation therapy) and who fit other specific criteria.

Patients will be randomly split into two groups. One group will receive standard treatment, which is surgery followed by chemotherapy. The other group will receive the experimental treatment, which is surgery followed by the personalized mRNA vaccine, an immunotherapy drug called a checkpoint inhibitor, and chemotherapy. The phase I study followed a similar treatment plan but did not have a control group receiving standard treatment for comparison.

The mRNA vaccine will be given in two phases: doses at the beginning of treatment prime the immune system, and later doses provide a boost. 

Data gathered from the phase II trial will be analyzed so researchers can better understand what factors help the vaccine work in some patients but not in others. And then, hopefully, find solutions to that problem. “It’s exciting to see that a personalized vaccine could enlist the immune system to fight pancreatic cancer,” says Balachandran. “Our longer-term hope is that we may be able to use such personalized vaccines to treat other deadly cancers.”

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