Pancreatic cancer is one of the deadliest forms of cancer, with very few effective treatments. But messenger RNA (mRNA) vaccines, famed for their ability to prevent COVID, are beginning to show promise against deadly cancer. In a recent early-stage trial, half of pancreatic cancer patients who received a personalized mRNA cancer vaccine after surgery had no recurrence of the tumor a year and a half later. The trial, which was described in a study published Wednesday in Naturewas small – with just 16 patients – and will need to be replicated in larger studies.
“I’m very supportive of the results,” says Drew Weissman, director of vaccine research and director of the Institute for RNA Innovation at the University of Pennsylvania, who is a pioneer of mRNA vaccines but was not involved with the new newspaper. He adds that “this is not a definitive proof-of-use study. Larger studies are needed to determine effectiveness.
Pancreatic ductal adenocarcinoma, the most common type of pancreatic cancer, has an 88 percent mortality rate. It is the third leading cause of cancer death in the United States and is becoming increasingly common. Surgery is the main form of treatment, but the cancer has a 90% recurrence rate after seven to nine months. Chemotherapy is only partially effective in delaying recurrence. Other treatments, such as immunotherapy, are mostly ineffective.
Pancreatic cancer often goes unnoticed until its later stages, when it is more difficult to treat. One of the reasons it’s so sneaky is that it generates relatively few of a type of surface protein, called neoantigens, that mark it as foreign and trigger an immune response. Scientists had noticed that people who had survived pancreatic cancer had a stronger response to these neo-antigens from T cells, a type of immune cell.
In the new study, Vinod Balachandran, an assistant surgeon at Memorial Sloan Kettering Cancer Center in New York, and his colleagues targeted neo-tumor antigens from pancreatic cancer patients using mRNA technology – the same technology used to create the remarkably effective COVID vaccines. The experimental vaccines used by Balachandran and his colleagues were produced by BioNTech, a company that developed one of the COVID vaccines with Pfizer. The researchers vaccinated a total of 16 patients. After surgically removing the tumors, they treated patients with mRNA vaccines tailored to each person’s specific cancer, as well as an adjuvant, a substance that increases the effects of vaccines. Fifteen of the participants were also treated with chemotherapy.
Eight of the 16 patients generated a strong T cell response to the vaccines. At a median follow-up of 18 months after treatment, these people had longer survival without their cancer recurring.
The study was small and only involved white patients. And the therapy, which is expensive, doesn’t work for everyone with pancreatic cancer. Still, experts say it’s a promising development for a disease with such limited treatment options.