LONDON, UK – Spur Therapeutics today released new data from the GALILEO-1 and GALILEO-2 trials of avigbagene parvec (FLT201), its investigational gene therapy for Gaucher disease type 1 (GD1), which highlight encouraging improvements in skeletal disease, a major and persistent source of morbidity in patients despite long-term standard-of-care treatment. These data are being presented this week during the International Working Group on Gaucher Disease (IWGGD) 2026 Symposium.
Bone disease associated with Gaucher disease is a persistent unmet need for affected individuals. Build-up of toxic substrate can lead to bone marrow infiltration, reduced bone mineral density (BMD), and increased risk of fractures and chronic pain, which may not be resolved even when the disease is considered well-controlled through conventional measures of hematologic and organ volume measurements. New findings from the GALILEO-1 and GALILEO-2 trials of FLT201 indicate potential to meaningfully address bone pathology for this population. Additional findings demonstrate the reversibility on markers of bone turnover that are negatively impacted by corticosteroids, a treatment required in the management of potential immune responses with gene therapy.
“Skeletal disease in Gaucher disease may develop silently and frequently persist even after years of treatment with standard therapy, so we recognize the clear need to address bone health as part of therapeutic innovation,” said Pilar Giraldo, MD, PhD, study author, investigator in the GALILEO-1 and GALILEO-2 studies and hematologist at Hospital Universitario Quironsalud de Zaragoza in Spain. “This study provides early evidence that bone disease in Gaucher patients can be improved beyond what is achievable with current therapies, which may ultimately translate into reduced fracture risk and decreased pain for patients. Importantly, the rapid reversal of steroid-related bone effects further informs how we can safely manage immune regimens for gene therapy in Gaucher patients who already have an underlying increased risk for bone pathology.”
As previously reported, these studies have evaluated adult GD1 patients who had been on stable ERT or SRT for at least two years prior to enrollment. Patients received FLT201 followed by an immune management regimen consisting of oral glucocorticosteroids initiated three weeks post-infusion, and all participants then transitioned into a long-term follow-up study. This analysis highlights data from four patients who were taken off prior enzyme replacement therapy (ERT) or substrate reduction therapy (SRT) following treatment.
As of November 20, 2025, this analysis identified notable changes following treatment with FLT201. Specifically:
- Reduced bone marrow burden: All patients exhibited moderate to severe bone marrow burden at baseline. One patient had a significant and clinically relevant improvement in bone marrow infiltration (BMB score reduced from 11 to 7 at month 24, with improvement seen as early as month 3).
- Improved bone mineral density: Most patients had low bone mineral density scores indicating elevated fracture risk at study entry. Over two years, improvements in BMD were observed. Notably, improvements were seen even among patients with otherwise well-controlled systemic disease.
- Reversible impact of corticosteroids on bone: Initial declines in markers of bone turnover (as expected with corticosteroid use) were reversible following discontinuation.
“These encouraging results highlight the potential beneficial effect of FLT201 on bone disease in GD1 patients. We believe the extended stability of GCase in the blood stream and within tissues that is seen with FLT201 may allow for deeper penetration into hard-to-reach tissues such as bone, which could explain this promising effect,” said Pamela Foulds, MD, Chief Medical Officer of Spur Therapeutics. “This data contributes to the strong body of evidence supporting FLT201 and we look forward to demonstrating this profile in a larger dataset through the Phase 3 trial we initiated this year.”
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 has a preclinical gene therapy candidate for Parkinson’s disease. Expanding our impact, and advancing the practice of genetic medicine.
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For more information, visit www.spurtherapeutics.com or connect with Spur on LinkedIn.
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