For more than a decade, a team of researchers at UHN's Princess Margaret Cancer Centre has been advancing a revolutionary approach to cancer treatment.
Their innovative work with porphysomes — light-activated nanoparticles — has now reached a pivotal milestone: Health Canada's approval to begin clinical trials.
This homegrown innovation, funded from its inception by the Terry Fox Research Institute (TFRI) with $14.8 million in support, along with significant contributions from The Princess Margaret Cancer Foundation (PMCF) through multiple initiatives, including the Innovation Accelerator Fund, represents a major step forward in personalized cancer care.
A vision for an advanced cancer treatment
The story began with a bold idea from Dr. Gang Zheng, a Senior Scientist and the Associate Research Director at the Princess Margaret. He envisioned using nanotechnology to both detect and treat cancer with unparalleled precision.
"Porphysomes were a game-changer from the moment we discovered them," says Dr. Zheng, who is also a Canada Research Chair in Cancer Nanomedicine, Tier I, and a professor at the University of Toronto (U of T). "Their unique ability to accumulate in tumours and respond to light makes them an incredibly powerful tool for imaging and therapy."
With initial support from TFRI and The PMCF, Dr. Zheng and his team explored the safety and efficacy of porphysomes across different cancer types. The nanoparticles' ability to make tumours "glow" under imaging significantly improved surgical precision, while their potential for photodynamic therapy (PDT) opened new doors for non-invasive treatments.
These findings, published in major scientific journals, laid the foundation for translating the research into clinical applications. Building on this success, the research team is actively exploring commercialization opportunities for porphysome-based therapeutics, with the goal of accelerating the journey from discovery to patient care and ensuring this Canadian innovation makes a lasting impact.
A decade of breakthroughs leading to the clinic
As the research progressed, key milestones brought porphysomes closer to patient care. The team successfully refined the technology, enhancing its drug delivery capabilities and therapeutic impact.
In recent pre-clinical studies, the team found that PDT with porphysomes can stimulate the body's immune response to fight cancer. This has the potential to stop the spread of cancer and destroy distant tumours.
The team will also explore the use of radioactively-labelled porphysomes and low doses of radiation to target deep-seated tumours, expanding the potential for porphysomes to effectively treat cancers in a minimally invasive way.
Dr. Jonathan Irish, a Senior Scientist and surgeon at the Princess Margaret, and a member of its Cancer Clinical Research Unit (CCRU), highlights the critical role of early support.
"We explored porphysomes' safety and effectiveness across various cancers in lab studies, utilizing these unique nanoparticles for imaging to guide surgery and for light-based treatments such as PDT, which involves administering and activating non-toxic photosensitizers within tissues to kill surrounding cells," explains Dr. Irish, who is also the Kevin and Sandra Sullivan Chair in Surgical Oncology and a professor and Head of the Division of Head & Neck Oncology and Reconstructive Surgery at the U of T.
"This research is incredibly fascinating. It's these eureka moments that drive us forward, and technology offers new directions and modalities we must explore," says Dr. Brian Wilson, a Senior Scientist at the Princess Margaret, a professor of Medical Biophysics at the U of T and the initial principal investigator of the TFRI-funded porphysomes project.
With continued investment from TFRI, the Ontario Institute for Cancer Research and The PMCF, the team advanced porphysomes toward regulatory approval.
Health Canada's recent authorization, for a first-in-human trial that will assess PET imaging with radiolabeled porphysomes for advanced ovarian cancer patients, is a testament to the strength of this pan-Canadian effort.
From research to reality: what's next?
With clinical trials set to begin soon, patients will be recruited to assess the safety and efficacy of porphysomes.
Dr. Amit Oza, a Senior Scientist and the Head of the Division of Medical Oncology and Hematology at the Princess Margaret, underscores the significance of this transition.
"Moving from preclinical research to patient trials is a critical step," says Dr. Oza, who is Medical Director of the CCRU and the Daniel E. Bergsagel Chair in Medical Oncology. "Porphysomes act like a Trojan horse, infiltrating tumours and activating treatment from within.
"We are entering a new era where precision-guided, minimally invasive cancer treatments could become a reality," says Dr. Oza, co-Director of the Drug Development Program, a scientist at the Ontario Cancer Institute and a professor in the Department of Medicine at the U of T.
Beyond these initial trials, the future looks bright. The team is already exploring ways to expand the technology's applications to other types of cancer and combination therapies.
The ultimate goal is to integrate porphysomes into standard oncology practice, improving outcomes for patients worldwide.
A Canadian success story with global impact
This achievement is more than just a scientific milestone — it is a testament to Canada's leadership in cancer innovation.
"This is a fully homegrown discovery, developed, tested and now moving to the clinic entirely within Canada and led by UHN," says Dr. Brad Wouters, Executive Vice President of Science & Research at UHN. "It's a shining example of what can be accomplished when researchers, clinicians and funding partners come together as one team to push the boundaries of what's possible."
The journey from bench to bedside is never easy, but with Health Canada's approval, porphysomes are poised to change the future of cancer treatment.
Thanks to the unwavering support of TFRI, The PMCF and other key partners, this Canadian innovation is on the cusp of making a global impact — one illuminated tumour at a time.
This work was supported by The Princess Margaret Cancer Foundation, the Terry Fox Research Institute, the Lotte & John Hecht Memorial Foundation, The Canadian Institutes of Health Research and the Ontario Institute for Cancer Research.
