I was told there wasn't anything more that could be done.
In the long struggle to extend immune therapies beyond blood cancers into the harder terrain of solid tumors, Canadian researchers have taken a meaningful step forward. Scientists at the University of Calgary and McMaster University have developed GCAR1, an engineered immune cell therapy that targets a marker found on sarcoma, brain, and kidney cancers — and early clinical results suggest it may be working. Two patients with a rare and aggressive sarcoma received the treatment in Calgary, with one surviving eighteen months beyond her prognosis and another watching lung tumors shrink or vanish. The work reminds us that the distance between a laboratory insight and a human life saved is sometimes shorter than we dare to hope.
- Solid tumors have long resisted CAR T-cell therapies that work well against blood cancers, leaving patients with sarcoma and brain cancer with few options — GCAR1 is a direct attempt to break that wall.
- Stéphanie Alain, given little time to live, gained eighteen months of life after receiving the experimental therapy, and the biological data her doctors collected from her treatment became the blueprint for what came next.
- A second patient, Kent B., watched multiple lung tumors shrink or disappear after receiving GCAR1 combined with a companion immunotherapy — results his doctors described as striking.
- The therapy moved from laboratory concept to human patient in under two years, a pace that reflects both the urgency of the need and the depth of the institutional collaboration behind it.
- Because the cancer marker GCAR1 targets also appears on glioblastoma and kidney cancers, researchers are already exploring whether the therapy can be adapted far beyond its original sarcoma focus.
Canadian researchers have developed an experimental immune therapy called GCAR1 that shows early promise against solid tumors — cancers that have largely resisted the CAR T-cell treatments now standard for blood cancers. The work comes from scientists at the University of Calgary's Charbonneau Cancer Institute and McMaster University, with findings published in companion papers in Nature and Nature Cancer.
The therapy works by engineering a patient's own immune cells to recognize a unique marker found on certain solid tumors, then reprogramming those cells in the laboratory to seek and destroy cancer cells bearing that marker. Solid tumors are notoriously difficult to treat this way — dense tissue can shield them from immune attack — making the early results all the more significant.
Two patients with alveolar soft-cell sarcoma, a rare and aggressive cancer, received GCAR1 at the Arthur J.E. Child Comprehensive Cancer Centre in Calgary. The first, Stéphanie Alain, lived eighteen months longer than her doctors had anticipated. The tissue and blood samples collected throughout her treatment gave the research team critical insight into how the therapy was functioning at the cellular level — insight that directly shaped what came next.
The second patient, a fifty-five-year-old Calgary man identified as Kent B., received GCAR1 alongside a companion immunotherapy. Before treatment, his cancer had spread to his lungs, with multiple tumors visible on CT scans. After treatment, many of those tumors shrank, and some disappeared entirely. One lesion measuring over two and a half centimeters shrank to less than one. 'I was told there wasn't anything more that could be done,' Kent said. 'After the second therapy the scans showed that many of the tumors shrank, and some had disappeared.'
The pace of the work has been remarkable. The team began focusing on the cancer target in 2021, had mouse study results within six months, and obtained approval to treat a human patient by 2023. The marker GCAR1 targets also appears on glioblastoma and kidney cancers, and preclinical studies at McMaster suggest the therapy may extend to those diseases as well. Researchers are already developing more advanced versions of GCAR and studying tumor samples from both patients to improve efficacy further.
A team of Canadian researchers has developed an experimental immune therapy that appears to work against solid tumors—a class of cancers that have largely resisted the CAR T-cell treatments now standard for blood cancers. The therapy, called GCAR1, was created by scientists at the University of Calgary's Charbonneau Cancer Institute and collaborators at McMaster University, and their findings appear in companion papers published in Nature and Nature Cancer.
The breakthrough hinges on identifying a unique marker present on certain solid tumors. Once the researchers spotted this target, they engineered CAR T cells—immune cells taken from a patient's own body and reprogrammed in the laboratory—to recognize and attack cancer cells bearing that marker. The approach is straightforward in concept but has proven remarkably difficult to execute in practice. Solid tumors, unlike blood cancers, sit in dense tissue that can shield them from immune attack. The fact that this therapy shows early promise suggests the researchers may have found a way around that fundamental obstacle.
Two Canadian patients with alveolar soft-cell sarcoma, a rare and aggressive malignancy, received GCAR1 treatment at the Arthur J.E. Child Comprehensive Cancer Centre in Calgary. The first patient, Stéphanie Alain, lived substantially longer than her doctors had anticipated—the therapy extended her expected survival by eighteen months. Her willingness to participate in the trial, and the detailed tissue and blood samples her doctors collected before and after treatment, gave the research team crucial insights into how the medicine was working at the cellular level. Dr. Sorana Morrissy, who led the data science effort, analyzed lung biopsies and thousands of individual cells from dozens of blood draws to understand what made the therapy effective.
Those insights informed the treatment of a second patient, a fifty-five-year-old man from Calgary, who received GCAR1 combined with a companion immunotherapy. His results have been striking. Before treatment, his cancer had spread to his lungs. CT scans showed multiple tumors. After the combined therapy, many of those tumors shrank, and some disappeared entirely. One lesion that measured over two and a half centimeters across shrunk to less than one centimeter. Another lesion that was visible on the first scan became barely detectable on the second. "I was told there wasn't anything more that could be done to treat my cancer," the patient, identified as Kent B., said. "After the second therapy the scans showed that many of the tumors shrank, and some had disappeared."
The speed at which this work moved from laboratory to patient is itself remarkable. Dr. Franz Zemp, the first author of the study, notes that the team focused on this particular cancer target beginning in 2021. Within six months of developing the therapy, they had results from mouse studies. The findings were compelling enough that they obtained approval to treat a patient by 2023—a translation from bench to bedside that would have seemed impossible just a few years ago. The work involved collaboration across multiple institutions: the University of Calgary, Cancer Care Alberta, Alberta Precision Laboratories, and Boreal Biomanufacturing at The Ottawa Hospital, which manufactured the virus used to engineer the CAR T cells.
The marker that GCAR1 targets is not limited to sarcoma. Researchers at McMaster University, led by Dr. Sheila Singh, have demonstrated in preclinical studies that the therapy shows promise against glioblastoma, one of the deadliest brain cancers. The same marker also appears on kidney cancers, suggesting the therapy could eventually be adapted to treat multiple cancer types. The team is already working on more advanced versions of GCAR and continues to study the tumor samples from both patients to understand how to make the medicine even more effective.
This work is part of a broader initiative at the University of Calgary's Cumming School of Medicine called Living Medicine, which focuses on therapies that harness the body's own cells, genes, and microbes to fight disease. The research was funded by philanthropic donations, grants from the Canadian Cancer Society, the Canadian Institutes of Health Research, and several cancer foundations. Dr. Douglas Mahoney, director of the Riddell Centre for Cancer Immunotherapy and principal investigator on the Nature Cancer study, emphasized that the advance reflects not just scientific discovery but the power of bringing together researchers, clinicians, and the broader community in sustained collaboration. Mahoney and Zemp hold a pending patent on the GCAR therapy.
Notable Quotes
I was told there wasn't anything more that could be done to treat my cancer. After the second therapy the scans showed that many of the tumors shrank, and some had disappeared.— Kent B., second patient treated with GCAR1
That speed of translation from the lab to the clinic is remarkable.— Dr. Franz Zemp, first author of the study
The Hearth Conversation Another angle on the story
Why does this matter? CAR T therapy already exists for blood cancers. What's different about tackling solid tumors?
Solid tumors are fundamentally harder to reach. They're embedded in tissue, surrounded by cells that can shield the cancer from immune attack. Blood cancers float freely in circulation, so engineered immune cells can find them easily. With solid tumors, you need to identify a marker that's unique enough that your therapy can distinguish cancer from healthy tissue. That's what took years to find.
And they found this marker by accident, or was it a deliberate search?
It was deliberate. The team had laser focus on this particular target starting in 2021. They weren't fishing blindly. Once they identified it, they built the therapy around it. The speed after that—six months to mouse data, approval by 2023—that's what's unusual.
The first patient, Stéphanie Alain, lived eighteen months longer than expected. That's significant, but it's one person. How do we know this isn't just luck?
You don't, not yet. That's why the second patient matters. He had a different disease presentation—metastatic cancer in his lungs—and they treated him differently, combining GCAR1 with another immunotherapy. The tumors shrank. That's two different patients, two different approaches, both showing response. It's still early, but it's not a single anecdote anymore.
What happens now? Do they move to larger trials?
They're studying the tumor samples from both patients to understand the mechanism better. They're developing more advanced versions of the therapy. And they're looking at other cancers—kidney, brain—where the same marker appears. The next step would be formal clinical trials, but that takes time and funding.
Is there a reason this came out of Canada specifically?
Partly infrastructure. The Riddell Centre at Calgary, Cancer Care Alberta, the manufacturing capacity at Ottawa Hospital—these institutions were already positioned to move quickly. But also culture. There's a real commitment to translational research here, to moving discoveries into patients' hands fast. That matters when you're racing against time.