RESEARCH DREAMS OF A VACCINE
Twenty years ago, Dr. Brad Nelson watched his mother-in-law struggle with ovarian cancer and wished he could do something to ease her suffering. The experience was so difficult and emotional that it propelled him to dedicate his career to cancer research. Before long, he became a firm believer that any cure for cancer must involve the patient’s own natural defences.
“Patients who mount a strong immune response against their tumour have better survival rates than patients who have a weaker immune response,” explains Nelson. “This, of course, stimulates interest in finding ways to enhance immune response in everybody to improve outcomes.”
Thanks to today’s advances in DNA sequencing and genomic technology, the Victoria-based scientist is currently overseeing breakthrough research aimed at developing personalized therapeutic vaccines to supercharge a patient’s immune system and attack cancerous tumours.
“When patients are diagnosed, they want to know, ‘ What should I be eating? Should I be exercising? How can I help my immune system?’” says Nelson, director of the BC Cancer Agency’s Deeley Research Centre in Victoria. “Yet beyond just taking care of themselves, it’s hard for patients to boost their immune system to the levels you need to eliminate your cancer.
“That’s where we come in: the idea is to give patients vaccines that educate the immune system to be able to recognize the tumour and launch a stronger attack.”
According to Nelson, the immune system has trouble distinguishing between tumour cells and normal tissue. But with recent advances in genomic technology, it’s now possible to analyze tumours, then identify the mutations that make them abnormal and cause them to grow and spread to other parts of the body.
This is helping researchers to develop new vaccines that help the immune system recognize tumour mutations. Because each patient’s tumour and immune system are unique, these vaccines will be personalized for each patient. They will be administered at the completion of standard treatment to ensure the immune system can recognize and eliminate any residual tumour cells that may have evaded treatment. The research project is partially funded by the CBCF’s BC/Yukon Region and the BC Cancer Agency.
The challenge, says Nelson, is that a typical tumour might have 100 mutations but a personalized vaccine would only target about five. “So how do you choose those five?” Tests are currently underway on mice because “it’s a convenient experimental model that allows you to answer questions quickly.” Human clinical trials are expected within three to five years.
Although there are other researchers in the United States and Europe working on similar projects, Canada is leading the way through collaboration. As Dr. Robert Holt, head of sequencing at the BC Cancer Agency’s Michael Smith Genome Sciences Centre in Vancouver and Nelson’s colleague on the personalized vaccine project, explains, Canada’s environment is unique because it has experts in genome sequencing, tumour DNA analysis and immunology all within one organization.
“Timelines for research of this nature are longer than we all would like them to be,” says Holt. “It generally takes a decade to develop a new immune intervention or drug or vaccine. [However,] there’s an increasing understanding of the interaction of the immune system and tumour development, and we’re among the leading centres in the world developing new approaches to be able to vaccinate against cancer.”
After two decades of studying the immune response to cancer, Nelson feels closer to a breast cancer breakthrough than ever before. Personalized therapeutic vaccines could be the next big thing.
“Based on what we know now, it’s a great idea that could have a major impact for a lot of patients,” he says. “When we get the immunotherapy working, we can start dialing back on the other treatments. We can start reducing the amount of chemotherapy that patients receive, the amount of radiation therapy, and start replacing that with more gentle therapies — not gentle against the tumour but gentle against the patient, more tolerable. Hopefully we can get patients’ own immune systems helping themselves.”