Spur Therapeutics is advancing FLT201, a novel adeno-associated virus (AAV) gene therapy, as a potential one-time treatment for Gaucher disease. The company recently announced positive feedback from the FDA regarding its end-of-Phase 2 meeting, paving the way for a Phase 3 trial expected to begin in the second half of 2025. Interim results from the Phase 1/2 GALILEO-1 clinical trial were presented at the 21st Annual WORLDSymposium, showcasing the therapy's potential to improve outcomes for patients with Gaucher disease.
GALILEO-1 Trial: Safety and Efficacy
The GALILEO-1 trial evaluated the safety and efficacy of FLT201 in adult patients with Gaucher disease type 1. The study treated six patients with a single infusion of FLT201 at a low dose of 4.5e11 vg/kg. Patients were followed for between nine and 17 months after dosing. All six patients were included in the safety analysis, while five were included in the efficacy analysis. Prior to the trial, all patients had been treated with enzyme replacement therapy (ERT) or substrate reduction therapy (SRT).
The data from the GALILEO-1 trial demonstrated a favorable safety and tolerability profile for FLT201, with no infusion reactions or dose-limiting toxicities reported. All treatment-related adverse events were mild to moderate in nature. The trial also showed durable reductions in glucosylsphingosine (lyso-Gb1), ranging from 33% to 96% in patients who entered the trial with high levels. One patient who entered the trial with well-controlled levels maintained stable lyso-Gb1 levels for more than a year after the withdrawal of prior therapy.
FDA Alignment on Phase 3 Trial Design
Spur Therapeutics has reached an agreement with the FDA on the design of a single-arm Phase 3 study to support potential accelerated approval of FLT201. The accelerated approval pathway will be based on reductions in lyso-Gb1 levels six months after dosing. Full approval would be based on improvement or maintenance of hemoglobin levels a year after dosing. The Phase 3 trial is expected to enroll approximately 40-45 patients and will be conducted at over 45 sites across the United States, Canada, the United Kingdom, Europe, Israel, and Latin America.
FLT201: A Potential New Standard of Care
FLT201 is designed to address the underlying cause of Gaucher disease by delivering a functional copy of the GBA1 gene, which is mutated in patients with the disease. The gene therapy leverages Spur's proprietary and potent AAVS3 capsid to deliver GCase85, a rationally engineered longer-acting version of the enzyme deficient in people with Gaucher disease. This approach aims to stop disease progression, reduce or eliminate symptoms, and allow patients to come off current lifelong treatments.
"We believe that FLT201 has the potential to be a first- and best-in-class gene therapy that sets a new standard of care for Gaucher disease," said Michael Parini, Spur's Chief Executive Officer. "We are moving expeditiously to get the Phase 3 trial underway with the goal of providing people with Gaucher a potentially transformative one-time therapy that eliminates or alleviates ongoing symptoms while dramatically reducing the treatment burden."
