Two doctors in Montreal are part of leading efforts to advance international clinical research into mRNA vaccines for cancer treatment. Two international clinical trials launched at the McGill University Health Centre (MUHC) are among the first in North America and worldwide to use mRNA vaccines to treat lung and bladder cancer. Dr. Ramy Saleh, medical oncologist at the MUHC and the medical director of oncology clinical trials at the Centre for Innovative Medicine at the Research Institute, says the vaccine’s goal is to prevent cancer from recurring. The vaccine is used in combination with immunotherapy and is for patients whose cancer has not metastasized — before Stage 4. “The worst thing that can happen to a patient with localized cancer is that they go through rigorous, intensive treatments, like chemotherapy, surgery or radiation, and then after all of that, you tell them a few months or years down the line, ‘your cancer came back’,” said Saleh, who is leading the bladder cancer trial. “To have a technology that we can give patients, which is easily given and ensures that their cancer doesn’t come back, is exciting, and it is also very empowering for the psychology of the patient.” Recurrence is high in bladder cancer, and it is also costly on the health-care system because of the intensive interventions it can require. Lung cancer is a prevalent health concern in Canada — it is the most commonly diagnosed cancer among men and women in the country. “When patients receive treatment and surgeries for bladder cancer, they are quite morbid surgeries, because you have to remove the whole bladder, or sometimes radiate the whole bladder, to make sure the cancer does not come back,” he said. “It’s great that cancer vaccines are focusing on diseases that actually cause a lot of recurrence and issues for the patients and for the health-care system.” Personalized medicine Dr. Jonathan Spicer, thoracic surgeon at the MUHC and scientist at the Cancer Research Program at the MUHC Research Institute, is helping lead the lung cancer clinical trial. Spicer says the mRNA vaccine is created from a sample of the patient’s tumour that is surgically removed, and the tumour’s genetics are analyzed and used to create a personalized vaccine for the patient. “We find these alterations in the tumor DNA that are different from the normal cells’ DNA and set the tumour apart, and the vaccine essentially copies those sections of DNA that are abnormal, but on an mRNA backbone,” Spicer said. “There are 34 that we try to identify, and they’re put together into a molecule or a drug delivery that contains the sequences of genetic code for all 34 of those abnormal sections of DNA. By injecting them into the patient, we allow their immune system to get primed against these abnormal pieces of DNA, so that if you have an immune cell that is set up to recognize that, and it sees a cancer cell expressing those abnormal pieces of DNA, it will go to kill that cancer cell.” Spicer says the way the vaccine is created makes treatment truly personalized for each individual. “Each mRNA therapy that’s developed is specific to that patient’s cancer, and this is sort of the hallmark of personalized medicine,” he said. “Preliminary data seem to suggest that we’re not seeing major toxicities that are life-altering for patients, and so the ability to deliver a highly personalized treatment that has relatively low toxicity that could change the cure rate for these very common and deadly cancers is extremely exciting.” Knowledge gained from pandemic Research into testing mRNA vaccines for cancer began in the 1990s. However, the COVID-19 pandemic gave doctors further insight into the potential of these vaccines, prompting the launch of multiple global clinical trials for mRNA vaccines for cancer treatment, Saleh said. “In 2020, we learnt more about how we should create COVID-19 vaccines; that’s when we understood the technology even more, and we became successful, and this is why you see an upward slope in the number of clinical trials for cancer vaccines,” he said. “In science, we are always ahead of our game. When we try to invent something, sometimes we put ideas in the drawer and then a few years later, when we know more, then we bring the technology back from the drawer.” Saleh said the growing number of global trials and promising preliminary results involving the mRNA vaccine is a game changer for the future of cancer treatment. “Those are two very positive signals that indicate that the future is bright for cancer vaccines,” he said.
