Some COVID-19 shots may be doing more than preventing a bad cough and fever.
Researchers are exploring whether mRNA vaccines designed to fight the coronavirus could help extend survival for people with advanced cancer who are receiving immunotherapy, a type of treatment that leverages the immune system to better fight cancer. Immunotherapy has shown particular success against lung cancer, kidney tumors and melanoma.
Before the first immunotherapy drugs were approved, in 2011, only 10 percent of people with melanoma lived for five years or more; today, more than half do. Lung cancer survival has also improved, climbing from 18 percent to about 30 percent over the past eight years.
Still, immunotherapy doesn’t work for everyone. Across all cancer types, only 20 to 40 percent of patients respond to this type of treatment. This has led researchers to look for ways to help more people benefit from the treatment.
mRNA vaccines ‘wake up the immune cells’
One promising field of study involves therapeutic cancer vaccines. Unlike shots that prevent people from being infected with measles or influenza viruses, therapeutic vaccines for cancer are designed to train the immune system to fight tumors.
Some of the cancer vaccines in development are personalized for each patient, using tissues from their tumors. Scientists include proteins from an individual’s tumor cells to design the vaccine, which takes one to two months to produce, in the hope of teaching the immune system to identify cancer cells as the enemy and destroy them. Other cancer vaccines train the immune system to target proteins that are shared across many kinds of cancers.
Long before the COVID-19 vaccine was developed, cancer scientists began trying to create therapeutic vaccines using mRNA, or messenger RNA, which carries the genetic information needed to produce proteins.
Scientists at the University of Florida were working on a therapeutic vaccine for brain tumors in 2016 when they made an interesting observation: Vaccines that used mRNA appeared able to train the immune system to kill tumors, even without using genetic material from the person’s cancer. In the experiments, mRNA vaccines appeared to “sensitize” cancer cells to immunotherapy, allowing the medications to work better, said Dr. Adam Grippin, a radiation oncologist now at the University of Texas MD Anderson Cancer Center in Houston.
“We think that the mRNA vaccine acts like a siren to wake up the immune cells inside the tumor,” Grippin said. “When that happens, those cells start attacking the tumor” from the inside.