Two-year follow-up data demonstrate sustained benefit, including improvements in pain, fatigue and bone health, following single low dose of avigbagene parvec (FLT201)
Robust improvements in lyso-Gb1, a surrogate biomarker for potential accelerated approval, in patients with elevated levels despite long-term treatment with existing therapies
New patient-reported outcomes show improvements or maintenance of physical and mental well-being
Initiated Phase 3 trial of avigbagene parvec in adults with Gaucher type 1
LONDON, Feb. 04, 2026 (GLOBE NEWSWIRE) -- Spur Therapeutics today announced updated Phase 1/2 data on avigbagene parvec (FLT201), its clinical-stage gene therapy candidate for Gaucher disease, demonstrating favorable safety, dramatic improvements in a validated biomarker of disease severity and treatment response, and sustained clinical benefit through two years of follow-up across all responsive patients. The data, presented in a platform presentation and three posters at the 22nd Annual WORLDSymposium™, also mark the first time the company is sharing patient-reported outcomes from the trial, which show improvements or maintenance of physical and mental well-being.
“The standard of care for Gaucher disease requires biweekly infusions, placing a significant burden on patients. Even with long-term treatment, many people continue to experience pain, fatigue, and bone disease,” said Professor Ida Schwartz, MD, PhD, an investigator in the Phase 1/2 GALILEO-1 and GALILEO-2 studies and head of the Metabolic Clinics at Hospital de Clinicas do Porto Alegre in Brazil. “The two-year dataset shows that a single low-dose infusion of avigbagene parvec enabled patients to discontinue their prior treatments while maintaining improved or stable clinical outcomes. These results underscore the potential of gene therapy to meaningfully reshape care.”
The presentations highlight data from four patients with Gaucher disease type 1 in the Phase 1/2 GALILEO-1 trial and GALILEO-2 long-term follow-up study who were taken off prior enzyme replacement therapy (ERT) or substrate reduction therapy (SRT) following treatment with a single infusion of avigbagene parvec at the low dose of 4.5e11 vg/kg. All of these patients discontinued ERT or SRT within 11 weeks of dosing and have remained off those therapies for 20-26 months as of the data cutoff.
As of November 20, 2025, the data showed:
- Continuous expression of GCase85, which Spur scientists engineered for enhanced stability over recombinant human GCase, ensuring constant exposure to the enzyme that is deficient in people with Gaucher disease.
- Rapid and sustained reductions in glucosylsphingosine (lyso-Gb1), ranging from 53 to 94 percent as of the two-year follow up assessment, in patients with elevated levels despite years of chronic therapy with ERT or SRT.
- A measure of the substrate buildup that results from GCase deficiency, lyso-Gb1 is a validated biomarker of disease severity and treatment response and is emerging as a potential new standard for regulatory approval pathways.
- Clearance of substrate buildup from the bone marrow in one patient.
- Bone disease is a key area of ongoing need, with most people with severe bone marrow burden showing no meaningful improvement after years on ERT.
- Meaningful improvements or maintenance within the average range for the US population in patient-reported outcomes assessing physical and mental well-being.
- Dramatic improvement in pain and fatigue in the one patient who entered the trial with debilitating symptoms.
- Improved or stable hemoglobin levels, platelet counts, and liver and spleen volumes.
- Favorable safety and tolerability, with no dose-limiting toxicities.
- No effect on the efficacy of existing treatments in the two patients who remained on their prior therapies.
Spur has initiated its planned Phase 3 trial of avigbagene parvec. The company has alignment with the US Food and Drug Administration on the design of a single-arm trial that could support both potential accelerated and full approval.
“From the outset, our goal has been to deliver a one-time gene therapy that reduces the treatment burden for people with Gaucher disease while alleviating ongoing symptoms,” said Pamela Foulds, MD, Chief Medical Officer of Spur Therapeutics. “These latest data demonstrate a favorable safety profile and durable improvements in important clinical outcomes. With meaningful improvements in patient-reported outcomes, we’re seeing the potential to have an impact on how patients feel and function. As we move into the Phase 3 trial, these results reinforce our conviction in avigbagene parvec’s potential to make a meaningful and lasting difference for people with Gaucher.”
About Spur Therapeutics
Spur Therapeutics is a clinical-stage biotechnology company focused on developing life-changing gene therapies for debilitating chronic conditions. By optimizing every component of its product candidates, Spur aims to unlock the true potential of gene therapy to realize outsized clinical results. Spur is advancing a breakthrough gene therapy candidate for Gaucher disease and a preclinical gene therapy candidate for Parkinson’s disease. Expanding our impact, and advancing the practice of genetic medicine.
Toward life-changing therapies, and brighter futures. Toward More™
For more information, visit www.spurtherapeutics.com or connect with Spur on LinkedIn.
Contact
Naomi Aoki
naomi.aoki@spurtherapeutics.com
+ 1 617 283 4298
