Prime Editing Gene Therapy: World-First CGD Cure for B.C. Patient at UBC-Affiliated Research

A Milestone in Gene Editing: B.C. Patient's Historic Cure

The world of medical research marked a pivotal moment recently with the announcement of the first-ever cure for chronic granulomatous disease (CGD) using prime editing gene therapy. Ty Sperle, an 18-year-old science student from Kelowna, British Columbia, became the trailblazing patient after undergoing the treatment. Diagnosed at age five with this rare immune disorder, Sperle endured recurrent infections, daily medications, and the constant threat of life-threatening complications. Now, free from his lifelong burden, his story highlights the transformative potential of advanced gene editing technologies developed through international collaboration, including key contributions from Canadian researchers.

Sperle's journey from diagnosis to cure underscores the rapid evolution of precision medicine. Long-term care at BC Children's Hospital in Vancouver, under pediatric immunologist Dr. Stuart Turvey, positioned him for this breakthrough trial. The treatment, part of Prime Medicine's PM359 program, was administered at CHU Sainte-Justine in Montreal, showcasing Canada's role in hosting cutting-edge clinical research affiliated with universities like the University of British Columbia (UBC) and Université de Montréal.

Understanding Chronic Granulomatous Disease (CGD)

Chronic granulomatous disease is a primary immunodeficiency disorder caused by mutations in genes encoding the NADPH oxidase complex, essential for phagocytes—such as neutrophils and macrophages—to generate superoxide radicals that kill ingested pathogens. The most common variant, affecting about 25-30% of cases, involves the p47phox subunit (encoded by NCF1 gene), as in Sperle's case. Without functional NADPH oxidase, patients form granulomas—inflammatory masses—that block organs and suffer recurrent bacterial and fungal infections.

In Canada, CGD affects roughly 1 in 200,000 to 250,000 individuals, but rare diseases collectively impact one in 12 Canadians—over three million people. At institutions like BC Children's Hospital, one in three pediatric admissions involves a rare disease, emphasizing the urgency for targeted therapies. Traditional management relies on prophylactic antibiotics and antifungals, but these are imperfect; bone marrow transplants offer a cure but require matched donors, unavailable for Sperle.

• Symptoms: Recurrent pneumonia, abscesses, osteomyelitis (as in Sperle's skull infection), gastrointestinal issues, and canker sores.
• Prognosis without treatment: Reduced life expectancy due to fatal infections.
• Prevalence: Fewer than 100 diagnosed cases in Canada over decades.

Sperle's experience—hospitalizations for lung and bone infections—mirrors the disease's toll, driving the need for innovative interventions rooted in genomic research at Canadian universities.

The Dawn of Prime Editing Technology

Prime editing, pioneered in 2019 by David Liu at Harvard's Broad Institute, represents a leap beyond CRISPR-Cas9. While CRISPR creates double-strand breaks (DSBs) that can cause unintended mutations (indels), prime editing uses a fusion of Cas9 nickase (nicks one strand), reverse transcriptase, and prime editing guide RNA (pegRNA). The pegRNA specifies the target site and template for precise insertions, deletions, or base changes without DSBs, achieving up to 89% accuracy in some models.

This versatility suits monogenic diseases like CGD, where single-nucleotide variants or small deletions (e.g., delGT in NCF1) predominate. Canadian researchers, including those at UBC's BC Children's Hospital Research Institute, have tracked these advances, integrating them into clinical translation. Dr. Turvey's lab, focused on innate immunity and precision health, exemplifies how university-led genomics informs patient care.

Ty Sperle's Treatment Journey Step-by-Step

Sperle's path began with referral by Dr. Turvey to Prime Medicine's Phase 1/2 trial (NCT06559176). Here's the ex vivo process:

1. Stem Cell Mobilization and Harvest: Sperle received medication to release CD34+ hematopoietic stem cells (HSCs) from bone marrow into blood, then collected via apheresis.
2. Ex Vivo Editing: HSCs treated with PM359—an all-RNA prime editor delivered by electroporation—correcting the delGT mutation in up to 83% of cells.
3. Myeloablative Conditioning: Chemotherapy to clear faulty marrow.
4. Infusion: Edited HSCs reinfused; they engraft, producing functional neutrophils (69-83% DHR+ via dihydrorhodamine assay).
5. Monitoring: Isolation in Montreal for weeks; rapid engraftment confirmed durable NADPH oxidase activity.

The procedure's uncertainty was daunting, but Sperle's trust in Turvey and Dr. Élie Haddad prevailed. Results, published in the New England Journal of Medicine (Dec 2025), confirmed cure—no infections, off meds.

Canadian Researchers at the Forefront

Dr. Stuart Turvey, Canada Research Chair in Pediatric Precision Health at UBC and BCCHR, played a crucial role. His lab's work on immune deficiencies tracked gene editing progress, leading to Sperle's referral. BCCHR, UBC's pediatric research arm, advances cellular therapies; recent efforts include helper T-cell generation for immunotherapy.

CHU Sainte-Justine, affiliated with Université de Montréal, hosted the trial—the only Canadian site—building on 2025's first prime editing administration. CIHR-funded initiatives like Care4Rare bolster genomic diagnostics, sequencing 10,000+ patients. UBC Okanagan, Sperle's alma mater, fosters biotech talent via programs linking to research jobs in genomics.

Explore opportunities in Canada's gene therapy ecosystem through Canadian university jobs.

Photo by Raül Bocache on Unsplash

Scientific Validation: NEJM Publication Insights

The landmark NEJM paper details two PM359 patients: rapid engraftment, high editing efficiency (69-83% corrected neutrophils), restored oxidase function, and safety (no serious adverse events). Funded by Prime Medicine, it validates ex vivo prime editing for CGD's p47phox subtype.

Editing precision minimizes off-target effects, a CRISPR limitation. Canadian perspectives, per Turvey's publications, emphasize translating such research into public health systems. This publication accelerates regulatory paths, with PM359 holding FDA orphan designations.

Implications for Rare Diseases in Canada

CGD's cure signals hope for 7,000+ rare diseases affecting 3M Canadians. Initiatives like Genome Canada's RD efforts and CIHR's burden studies (prevalence, $1B+ annual costs) gain momentum. University research hubs—UBC, McGill, UofT—drive diagnostics via whole-genome sequencing, reducing diagnosis odysseys (avg. 5 years).

• Challenges: Access equity, high costs ($1M+ per treatment).
• Solutions: Public-private partnerships, as in Sperle's publicly funded care.
• Opportunities: Training next-gen researchers via academic career advice.

B.C. Health Minister Josie Osborne hailed it as proof of "smart investment in science."

Life After Cure: Sperle's New Normal

Post-treatment, Sperle resumed UBC studies, medication-free. No canker sores, infection fears gone—he camps freely. "Insane shock," he said, crediting Turvey's confidence. His mother wept with joy. This personal triumph inspires rare disease families, showing cures are attainable.

Future Outlook: Scaling Prime Editing in Canada

Prime Medicine advances PM359; more sites planned. Canadian unis expand: UBC's gene therapy for skin diseases, McGill's CF prime editing. Policy needs: National RD strategy for therapies. Students eyeing biotech can pursue faculty positions or research jobs in genomics.

Challenges include off-target editing refinement and in vivo delivery. Optimism prevails, per Turvey: "A dream come true."

Canadian Higher Education's Pivotal Role

Universities like UBC (Turvey's Tier 1 Chair) and UdeM drive gene editing. BCCHR's translational focus—innate immunity, cellular therapies—exemplifies. Programs train PhDs for industry; check postdoc opportunities. This cure elevates Canada's global standing in precision medicine.

Photo by Brett Jordan on Unsplash

Path Forward: Actionable Insights for Researchers and Patients

For academics: Collaborate via CIHR grants. Patients: Join networks like CORD. Sperle's case proves persistence yields cures. Explore Rate My Professor for gene therapy experts, higher ed jobs in biotech, career advice, and university jobs to advance this field. The future of rare disease treatment is here—powered by Canadian innovation.