Cancer treatments may get a boost from mRNA COVID vaccines

The mRNA COVID-19 vaccines might make some cancer treatments more effective.

Lung cancer patients who received the vaccine within a few months of immunotherapy, which revs up the immune system, lived nearly twice as long as unvaccinated patients, researchers report October 22 in Nature. The team observed something similar in people with melanoma, says Elias Sayour, a pediatric oncologist at the University of Florida College of Medicine in Gainesville.

The correlation suggests that mRNA vaccines — even those not designed for cancer ­— could make tumors more sensitive to current therapies. That’s an exciting finding, says Hua Wang, a cancer vaccine researcher at the University of Illinois Urbana-Champaign, who was not involved in the work. “It’s definitely interesting. It’s definitely important.”

In a time when mRNA COVID vaccines face increasing public and government skepticism, the study offers new evidence that their benefits may extend beyond protection from infectious diseases, Wang says.

Scientists already had clues about the anticancer effects of mRNA vaccines. An experimental mRNA vaccine given to tumor-bearing mice, for instance, made immunotherapy drugs work better, Sayour’s team reported in July in Nature Biomedical Engineering.

mRNA vaccines are typically thought of as the immune system’s teachers. For example, the COVID-19 vaccines include mRNA — a molecular messenger within cells — that carries the code for assembling a harmless bit of the coronavirus spike protein. The body uses that mRNA to build the protein, which the immune system then learns to recognize. mRNA cancer vaccines operate similarly but encode snippets of tumor proteins rather than viral proteins.

Sayour’s experimental vaccine was entirely different. It didn’t include tumor mRNA but still had antitumor powers. When paired with immunotherapy drugs, the mRNA itself — not what it encoded — rallied the immune system to fight cancer, his team discovered.

That finding inspired the new study. If the experimental mRNA vaccine could trigger an anticancer response, maybe other mRNA vaccines could, too. Millions of people, including cancer patients with electronic health records tracking their outcomes, have received the COVID-19 shots. Sayour’s team just had to look at the data.  

The researchers analyzed the records of roughly 1,000 people with non-small cell lung cancer, all of whom had received a type of immunotherapy drug called a checkpoint inhibitor. Nearly 200 of these patients had also received an mRNA COVID vaccine within 100 days of their drug treatment. Three years after diagnosis, 56 percent of vaccinated patients were still alive, compared with 31 percent of unvaccinated patients, the researchers report. They saw largely the same story in patients with advanced melanoma.

Such results “were not at all expected,” writes Eric Topol, a cardiologist at Scripps Research in La Jolla, Calif., who covers biomedical advances in the newsletter Ground Truths. He calls the work a “seminal paper” that provides “compelling data.” Some of those data include lab work in tumor-bearing mice.

In animals receiving immunotherapy, the mRNA vaccine switches on a powerful molecular siren, Sayour says. It’s like a 911 call that alerts the immune system to start fighting cancer. And the COVID vaccine wasn’t the only siren starter, either. A different type of mRNA vaccine prompted the same response, though non-mRNA vaccines did not, the team found.

Still, it’s too early to say whether combining immunotherapy with nonspecific mRNA vaccines is beneficial for cancer patients, Wang says. Sayour agrees. “It’s important for people to understand that this isn’t proven yet.” For that, they need a clinical trial, which his team is working on. They hope to start enrolling patients by year’s end.

If mRNA COVID vaccines do make certain immunotherapies work better, that would be a “paradigm shift in the cancer field,” Sayour says. It would mean that doctors already have at their fingertips a widely available, tried-and-tested option to help treat patients with aggressive cancers.

“I really do hope that the COVID-19 mRNA vaccines are that universal tool,” Sayour says. But even if they’re not, he’s optimistic that scientists will be able to design an mRNA vaccine that is.