Precision medicine and what it means for Canadians
How personal will personalized medicine become? One only needs to look at how treatments are evolving in cancer to get an idea. Research is already underway to see if a piece of a person’s cancerous tumour can provide enough genomic information to help develop a cancer vaccine that will wake up that person’s own immune system to target their specific cancer.
“Five to ten years ago this was unimaginable,” said Laura Shields, director of medical strategy at Hoffmann-La Roche Limited (Roche Canada). “It’s completely challenging the way clinicians provide care.”
Thanks to advances in genomic profiling and personalized medicine, the world is moving away from a one-size fits all model, where all lung cancer patients receive the same treatment despite specific patients’ individual characteristics, to identifying specific differences each person’s tumour may have.
“We’re using those differences to refine diagnosis, treatment and management of the disease,” explains Dr. Suzanne Kamel-Reid, chief of clinical laboratory genetics with the University Health Network and professor at the University of Toronto.
The use of genetics has long been used in the diagnosis and treatment of other diseases, such as pediatric syndromes. However, it’s only in the last 10 to 15 years that it has been used in oncology to better our understanding of what’s happening with the disease, resulting in more targeted treatments.
It is already improving patient outcomes. “Knowing the genetic composition of certain forms of leukemia is proving to be very effective,” said Kamel-Reid. “We can use the genetic profile of the leukemia to identify specific changes that occur, which in turn helps us determine the treatments that will work, those that won’t work and to determine when a patient loses response to the therapy they are receiving and should be switched to a different therapy.”
Genomic profiling of solid tumours such as lung cancer and melanoma is also being used effectively to determine if a patient is eligible for a therapy that is potentially less toxic and more tolerable than chemotherapy. This is expected to enhance the quality of life and potentially extend lives by slowing the progression of the disease.
Kamel-Reid sees gene profiling as a win-win. “It helps make better use of our health care dollars because you are able to more precisely determine what may or may not work for a patient in terms of treatment. A patient is getting a therapy that is more effective, and the hospital is saving money because patients spend less time in hospital and/or have fewer adverse events that require management.”
For Shields, personalized medicine is at a tipping point. “It’s been almost 20 years since the first targeted therapy for HER2-positive breast cancer was approved. Looking at the options that are on the table today and what is in development, it’s remarkable to see just how far we’ve come,” she said. “There is a lot more information available for patients and clinicians to understand what’s driving their disease. When you understand the mechanism of what’s happening, you can be more selective in choosing treatments that will target what’s really going on in the body. It’s no longer single biomarker, single drug.”
While the use of genomic profiling is increasing, it is likely not as widely employed as it could be because of funding and regulatory constraints. “Even though we know profiling and precision medicine is only going to improve how we treat and manage patients, we are still learning when such technology should be used optimally, and how to interpret and report results that can be quite complex in nature,” said Kamel-Reid. “Across Canada, ministries of health need to agree on what [genomic profiling tests] we should offer in terms of standard of care. Those discussions are happening.”
Another critical challenge for patients is access to targeted therapies given most of the work is being done in clinical trial settings. While genomic profiling is becoming an important tool to support the diagnosis and treatment of many cancer patients, some of the targeted therapies available in other countries are not available or funded in Canada.
Finding a sustainable way to resolve these challenges will be critical as scientific advances continue to drive this new era of personalized medicines. Genomic profiling is now making it possible for clinicians to look beyond the immediate cancerous tumour to identify treatments that address a particular genetic mutation that may drive the development of many types of cancer.
“[Globally] we are seeing the use of novel trial designs within larger drug development plans that are driven by biomarkers as opposed to tumour type. This is challenging the system,” said Shields. “It’s exciting to see this change in mindset that could bring innovative treatments to patients earlier with appropriate safeguards in place through these trials. I look forward to seeing it in Canada.”