Could COVID-19 vaccines help cancer treatments work better?
Scientists in the United States have found that people who were treated for advanced lung and skin cancer lived longer if they were given a COVID-19 vaccine within the first 100 days of treatment.
Preliminary research published on Thursday in the science journal Nature found mRNA, the molecule powering vaccines like Pfizer and Moderna, appeared to help certain kinds of immunotherapy work better.
But another researcher, not involved in the study, cautions that the study "demonstrates association, not proof" of effectiveness.
While working to developed personalised mRNA vaccines to treat cancer, researchers at the MD Anderson Cancer Center in Houston and the University of Florida hypothesised that even an over-the-counter COVID-19 vaccine might work with existing cancer treatments too.
The team analysed records of nearly 1,000 advanced cancer patients undergoing a certain type of treatment at MD Anderson, comparing those who had received a Pfizer or Moderna shot with those who hadn't.
Lung cancer patients who were vaccinated in the first 100 days of treatment were nearly twice as likely to be alive three years later than those who didn't receive a shot, while melanoma patients experienced significantly longer median survival times if they had received a shot.
"Surprisingly, patients with tumours that don’t typically respond well to immunotherapy also saw very strong benefits, with nearly fivefold improvement in three-year overall survival," the report's authors wrote.
The researchers said they were preparing to test the treatment strategy with a nationwide clinical trial in people with lung cancer.
"This study will tell us whether COVID-19 mRNA vaccines should be included as part of the standard of care for patients receiving an immune checkpoint inhibitor," MD Anderson Cancer Center researcher and study author Adam Grippin wrote.
"Ultimately, we hope that this approach will help many patients who are treated with immune therapy, and especially those who currently lack effective treatment options."
How does it work?
Messenger RNA, or mRNA, is found in every cell, containing genetic instructions to create proteins. Scientists believe it can be used to train immune cells to spot patients' tumours.
Healthy immune systems can kill cancer cells before they become a threat, but some cancer cells adapt themselves in order to camouflage warning signs to immune systems. Cancer treatments called "checkpoint inhibitors" work to undermine that camouflage. But this treatment doesn't always work.
Scientists around the world have been devising ways to use mRNA to train immune cells to spot tumours, but the US scientists wondered whether a generic mRNA could help checkpoint inhibitor treatment to work better.
In Australia, the BASE mRNA facility at The University of Queensland is dedicated to researching mRNA cancer vaccines.
Deputy director of the BASE, associate professor Seth Cheetham, who was not involved in the US research, said that "while very promising" a key limitation of the data was that it was retrospective, "which demonstrates association, not proof."
"Despite lining up with laboratory models and experiments from patient blood, a gold-standard randomised controlled trial is required to definitively prove that mRNA COVID vaccines are effective in cancer treatment," he said.
However, Cheetham said if the confirmatory trials are successful, "doctors may soon have an unexpected, powerful new option for treating cancer".
