After years in the lab, researchers are finally seeing their efforts come to fruition, with breakthroughs in the development of vaccines to treat and potentially cure cancer.
Over the last decade, scientists have been looking at therapeutic vaccines that offer the immune system a boost to help it fight off cancer. Many of these vaccines are destroying cancer cells, stopping tumors from growing and spreading, and sometimes keeping cancer from coming back.
mRNA vaccines are at the top of the list for new immunotherapeutic cancer treatments. How do they work?
Cancer cells evade the immune system by growing and dividing faster than the immune system can handle. They are also good at deceiving our immune system cells to prevent them from attacking.
mRNA vaccines are custom built from the neoantigens (cancer fingerprint proteins) found in the patient’s surgically removed tumor cells. The neoantigens in the vaccine train the immune system to recognize and attack any cancer cells that contain the fingerprint proteins on their surface.
The immune system’s cells’ exposure to the neoantigens in the mRNA vaccine arms the immune system with the ability to fight off cancer cells that it may encounter. Immune system cells remember the protein structure and antibodies circulate the body—all seeking tumor cells and marking them for destruction.
“Harnessing the immune system is the only way you can get down to ‘single cell’ kill. This is because, if appropriately stimulated, immune system cells can travel anywhere in the body, attack cancer where it is, and keep proliferating and killing until the cancer is gone,” Nora Disis, MD, director of the University of Washington’s Cancer Vaccine Institute, told Breaking Cancer News.
Some clinical trials show that increasing the capabilities of the immune system with an immunotherapy drug/standard of care (SOC) medications along with a specialized mRNA vaccine with multiple neoantigens can help the body better see and fight off cancer cells.
A small but significant study with an mRNA vaccine on pancreatic ductal adenocarcinoma (PDAC) finds half of patients are cancer-free at 18 months.
The results of a landmark study, funded by the National Institutes of Health (NIH), led by Vinod Balachandran, MD, Memorial Sloan Kettering Cancer Center (MSKCC), are promising in minimizing tumor regression and increasing the survival rate. Standard of care treatment plus a personalized mRNA vaccine may be the future of treatment for PDAC.
And while this therapy is still in its early days, the study has shown that at 18 months post-treatment, half of the patients had not had recurrence of cancer.
Eventually, vaccines may be available for every type of breast cancer.
In late 2022, a team let by Nora Disis, MD, director of the University of Washington’s Cancer Vaccine Institute, showed their DNA-based vaccine teaches the immune system to spot a mutated HER2 protein, a common driver of breast cancer.
Women with either remission following treatment or who had slow-growing tumors were vaccinated. The team found that after a decade, 80% of the patients were still alive. There is a larger phase 2 study underway.
The next clinical trial which is ongoing right now is a large, randomized study of the vaccine in women with HER2 low, ER negative breast cancer,” Disis told Breaking Cancer News. “If these patients don’t have a complete clinical response after initial chemotherapy, they will receive the vaccine versus an immune modulating agent. These women are at high risk for recurrence- so our hope it that the vaccine will prevent this.”
Susan Domchek, MD, director of the Basser Cancer Center at Penn Medicine, has vaccinated a small group of healthy women harboring the BRCA mutation gene that puts them at high risk of developing breast cancer. The vaccine teaches the immune system to look for an enzyme called telomerase, which is found in high quantities in cancer cells. This vaccine is predicted to kill cancer cells before they can form tumors.
Similarly, researchers at the Cleveland Clinic led a study vaccinating healthy women with a BRCA or PALB2 mutation. This vaccine could be safe option for women who are past their child-bearing years.
Personalized treatment is bringing hope to patients with metastatic colorectal cancer—the second leading cause of cancer death in the U.S.
A personalized mRNA immunotherapy program called GRANITE from Gritstone Bio, a clinical-stage biotechnology company, has been used to treat patients with metastatic colorectal cancer. Results from late-stage studies show that the survival of the population was greatly extended compared to those without the treatment.
“The survival of the (treatment) population was hugely extended compared to what you’d expect…that’s what we saw in half the subjects. The other half we saw no evidence of benefit at all, and they all sadly progressed and died at the expected rate which is after around seven months,” Andrew Allen, MD, PhD, CEO of Gritstone Bio, told Breaking Cancer News.
Phase 2 studies show promising results in significantly reducing the risk of recurrence/death in patients late-stage melanoma.
Moderna’s personalized mRNA vaccine in combination with an immunotherapy drug, Keytruda (Merck), has shown encouraging results in patients with late-stage melanoma. The trial found that of the patients who received the immunotherapy drug alone, 40% had recurrence of cancer during the two-year follow-up.
However, only 22.4% of patients who received immunotherapy with the mRNA vaccine had cancer recurrence.
Praveen Aanur, Vice President of the Therapeutic Area Head for Oncology Development at Moderna told Breaking Cancer News, “The combination regimen was well tolerated without adding any significant long-term toxicity to the safety associated with Keytruda monotherapy alone.”
A key step in cancer vaccine development is enrolling in clinical trials.
Those at high risk for cancer or who already have cancer can look for a vaccine trial to participate in by going to www.clinicaltrials.gov. Late-stage clinical trials are underway or not far out of sight. There’s hope for long-term survival and even cures for many tumors.
