A groundbreaking Canadian gene therapy trial has demonstrated remarkable success in treating Fabry disease, a rare genetic disorder that can damage vital organs and significantly shorten lifespan. The experimental treatment, administered at three medical centers across Canada, has enabled patients to produce their own functional enzymes, potentially eliminating the need for lifelong biweekly enzyme replacement therapy.
The results of this world-first, multi-center trial were published in Nature Communications on February 25th, marking a significant milestone in the treatment of this rare disease.
Transformative Results for Patients
Darren Bidulka, a 52-year-old patient who received the experimental therapy at Foothills Medical Centre (FMC) in Calgary in 2017, has experienced life-changing benefits. Prior to treatment, like all Fabry patients, he required enzyme replacement therapy (ERT) every two weeks to manage his condition.
"I'm really happy that this worked," Bidulka stated. "I can lead a more normal life now, without scheduling enzyme therapy every two weeks. I consider this a great success."
Bidulka is one of three patients who have been able to discontinue their enzyme replacement therapy following the gene therapy treatment, with all remaining stable since the intervention.
Scientific Breakthrough in Gene Therapy
The trial, led by Dr. Aneal Khan, an Alberta Health Services medical geneticist, utilized an innovative approach to address the fundamental genetic defect in Fabry disease.
"To date, we can say that the gene therapy has either partially or fully restored enzyme levels to a point where they are no longer considered deficient," explained Dr. Khan, who is also affiliated with the Alberta Children's Hospital Research Institute and Cumming School of Medicine at the University of Calgary. "These results show that just one treatment of gene therapy was enough to benefit patients. Now we need to see whether this single dose can last for the long term."
Fabry disease results from mutations in the GLA gene, which prevents patients from producing a functional version of an enzyme that breaks down certain fats. Without treatment, this leads to harmful accumulation in the kidneys, heart, and brain. The disease significantly reduces life expectancy, with untreated men living an average of 58 years and women 75 years.
Innovative Treatment Methodology
The experimental procedure involved several sophisticated steps:
- Collection of each patient's own blood stem cells
- Modification of these cells using a specially engineered lentivirus containing functional copies of the GLA gene
- Transplantation of the modified stem cells back into the patients
This marked the first trial in Canada to utilize a lentivirus for gene therapy. The virus was developed at Princess Margaret Cancer Centre in Toronto, where researchers removed its disease-causing capabilities and enhanced it with a working copy of the GLA gene.
All five male participants in the study began producing the corrected enzyme at near-normal levels within just one week of treatment. Based on these promising results, Health Canada approved all participants to discontinue their intravenous enzyme therapy if they chose to do so.
Two Decades of Research Culminate in Success
Dr. Jeffrey Medin, now the MACC Fund Professor at the Medical College of Wisconsin and Affiliate Scientist at University Health Network in Toronto, pioneered the treatment during his tenure as Senior Scientist at Princess Margaret Cancer Centre.
"After 20 years of working on this treatment, to see that patients could end up making their own enzyme, and that the treatment effect was sustained, is satisfying. We are elated!" Dr. Medin remarked.
Collaborative Effort Across Multiple Centers
The trial was conducted at three Canadian medical facilities: Foothills Medical Centre in Calgary, Princess Margaret Cancer Centre in Toronto, and Queen Elizabeth II Health Sciences Centre in Halifax.
Dr. Khan emphasized that the success of the Calgary arm of the trial was the result of extensive collaboration: "The contributions of so many people in Calgary were instrumental for the success of this trial. Everyone played a part, including AHS and the U of C. This shows the transformational power of doing clinical trials and the importance of research."
Key contributors included Shelly Jelinski, clinical research coordinator at Alberta Children's Hospital; Dr. Ahsan Chaudhry, an oncologist with the Alberta Blood and Marrow Transplant Program; Nicole Prokopishyn, director of the Cellular Therapy Lab at Alberta Precision Laboratories; and hematologists Dr. Peter Duggan, Dr. Andrew Daly, and Dr. John Klassen.
Future Outlook and Implications
While the initial results are promising, researchers will continue to monitor each patient for at least five years following their treatment. Clinicians caution that extensive additional testing will be required before this experimental approach can become a standard of care.
Fabry disease affects approximately one in 40,000 to 60,000 people, with around 500 known cases in Canada, though the actual number may be higher due to diagnostic challenges.
For Bidulka, who now resides in Vancouver, the implications extend far beyond his personal experience: "This research is also incredibly important for many patients all over the world, who will benefit from these findings. What an amazing result and an utterly fascinating experience."
This breakthrough represents a potential paradigm shift in the management of Fabry disease, offering hope that a single treatment could replace the need for lifelong enzyme therapy and significantly improve patients' quality of life.
