WHAT IS IMMUNOTHERAPY?
Our immune system provides an amazing line of defense against a whole host of viruses and bacteria. Researchers have found the immune system even mounts its own attacks when cancer begins. So why does it fail? And how can we help it succeed?
Some of the world’s top immunologists in The Princess Margaret’s Tumor Immunotherapy Program (TIP) are now hard at work finding the answers to these crucial questions. Their research thus far has been cutting-edge, producing results that are expected to transform the face of personalized cancer treatment in Canada.
Immunotherapy is based on the principle that, by properly stimulating the immune system, we can equip the body with the necessary strength and tools to combat tumor growth. Cancer-treating immunotherapy is particularly appealing because it specifically targets tumors with limited side effects, as opposed to chemotherapy. In addition, it offers a sustainable approach to fighting cancer, utilizing long-term immune surveillance so that the cancer cannot return.
Our vision is to continue to build and enhance our Tumor Immunotherapy Program at The Princess Margaret. This program is the first of its kind in Canada, and one of only a handful around the world. The program has the expertise to harness the power of the immune system with the goal of providing:
- Life-saving clinical trials;
- Genetically engineered T-cells, specific to a patient’s tumor;
- Drugs that stimulate the immune system to fight cancer.
Our goal is for each patient who comes through our doors to be treated using personalized cancer therapies. Immunotherapy plays an important role in bringing us closer to achieving this goal.
BLOCKBUSTER DRUGS IN IMMUNOTHERAPY
Today our physicians are collaborating with pharmaceutical companies and scientists to take new strategies tested in the lab to cancer patients.
Checkpoint inhibitors are a promising new class of drugs that are being explored at The Princess Margaret. Our immune system contains various regulatory checkpoints, or “immunological brakes,” which act to inhibit the body’s T-cell response. While this can be useful in certain situations, such as reducing immune hyperactivity, these brakes ultimately hinder the body’s capacity to ward off cancer. Checkpoint inhibitors work to reverse this activity – releasing the brakes and unleashing the powerful immune killer cells to effectively destroy tumor cells.
Keytruda (pembrolizumab) is one such checkpoint inhibitor drug that is being tested by our team. Studies have proven successful thus far, and have shown that various types of cancer can shrink after treatment with this drug. On June 8, 2015, Merck Canada announced the conditional approval of Keytruda for advanced melanoma treatment.
"The conditional approval of this new product in Canada marks a new era in how advanced melanoma will be treated in this population with a high unmet medical need," said Dr. Marcus Butler, Medical Oncologist at The Princess Margaret and Director of Princess Margaret Immune Monitoring Laboratory. "For patients suffering from symptoms of their advanced disease, the product is not only effective, but also well-tolerated."
One particularly inspiring case is that of Trent Krajaefski, who was admitted to The Princess Margaret with Stage 4 melanoma - the most serious form of skin cancer. Given his resistance to chemotherapy, he was admitted into an immunotherapy clinical trial, in which he was given Keytruda. We are happy to share that his cancer is now diminished.
CLINICAL TRIALS: BRINGING NEW HOPE TO PATIENTS
Researchers are also working on alternative mechanisms, beyond the use of checkpoint inhibitors, to recruit the immune system to fight cancer.
TIP Program Director, Dr. Pamela Ohashi, and her team, have recently opened the first clinical trial in Canada using a specific kind of immunotherapy called “Adoptive T-cell Therapy.” The clinical trial involves cancer fighting T-cells, the workhorses of the immune system, which are extracted from a patient’s tumor. Scientists use growth stimulants to dramatically increase the number of these T-cells and then they are transferred back to the patient in order to invoke a stronger immune attack against the patient’s cancer.
We are happy to share with you that the first group of patients in this trial were admitted and treated in 2013. We are now working on immunotherapy clinical trials involving ovarian cancer and mesothelioma (cancer in the lining of the lungs).
MONITORING PATIENTS’ RESPONSE TO IMMUNOTHERAPY
While we are very excited about the prospect of immunotherapy as a new cancer treatment, we are also aware of its potential side effects and limitations. We have therefore established a comprehensive immune monitoring program, designed to enable researchers to accurately assess patient responses to immunotherapy, and ultimately determine the success of treatments. The program will include a repository of patient samples, which will provide valuable information for understanding why some patients have an immune system that can mount a strong response to tumors, while other patients’ immune systems do not work as effectively.