Spur Therapeutics Continues to Make Progress in Evaluation of Gaucher Disease Gene Therapy FLT201
The phase 1/2 GALILEO-1 trial has completed enrollment and a phase 3 trial is planned for 2025.
Spur Therapeutics (formerly known as Freeline Therapeutics) has announced newly updated results from its now fully-enrolled phase 1/2 GALILEO-1 clinical trial (NCT05324943) evaluating FLT201, an adeno-associated virus (AAV) vector-based gene therapy intended to treat Gaucher disease, along with updated plans for a new phase 3 clinical trial for FLT201.1
Among 5 patients treated in GALILEO-1 who were evaluable for efficacy as of a June 30, 2024 data cut-off, normal levels of hemoglobin and platelets were maintained, or improvement to normal levels was observed in patients who did not already have normal levels. Four of the 5 patients had previously had persistently high levels of the Gaucher-specific biomarker glucosylsphingosine (lyso-Gb1) while on previous treatment with currently available therapies, and all 4 of these patients experienced dramatic reductions in lyso-Gb1 levels after treatment with FLT201. Additionally, 1 of the 5 patients who had had well-controlled lyso-Gb1 levels before treatment with the gene therapy maintained these levels after treatment. Furthermore, Spur reported that all 5 patients showed improvement in bone marrow burden posttreatment. Notably, 1 patient who had entered the trial with debilitating chronic pain and fatigue reported clinically-relevant improvements in said pain and fatigue, along with improved function, after treatment.
Spur pointed out that 2 patients who had antibodies to the disease-targeted enzyme glucocerebrosidase (GCase) continued to experience posttreatment improvements from baseline in areas including lyso-Gb1 levels and bone marrow burden and maintenance of normal hemoglobin and platelets after the detection of the antibodies. It was noted that in one patient who had more than 3 months of follow-up after detection of antibodies, the antibody levels appeared to be transient.
Spur characterized the safety and tolerability of FLT201 as “favorable” based on all 6 patients who were treated in GALILEO-1. Follow-up for 4 of the 6 patients ranged from 16 to 38 weeks posttreatment, with the other 2 patients having a completed the full 9 month follow-up period. One of the 6 patients was not included in the efficacy analysis because they had preexisting neutralizing antibodies to the AAVS3 capsid at levels below the protocol’s cut-off.
All patients in the study received a single dose of 4.5x1011 vg/kg, which the company intends to use in the planned phase 3 clinical trial that it expects to initiate in 2025. Spur noted that it plans to report additional results from GALILEO-1 before the end of 2024.
“We are very pleased with the progress of FLT201,” Michael Parini, the chief executive officer of Spur Therapeutics, said in a statement.1 “The data from the GALILEO-1 trial strengthen our conviction in FLT201’s potential to set a new standard of care for Gaucher disease and give us confidence to move forward at the current dose, which has shown strong signals of efficacy combined with a favorable safety and tolerability profile. We are preparing to start the phase 3 trial next year and are committed to bringing forward what we believe is a first- and best-in-class gene therapy to redefine the treatment landscape for Gaucher disease.”
Spur Therapeutics recently changed its name from “Freeline Therapeutics” after its June 2024 acquisition of Swan Bio, which is developing SBT101, an investigational gene therapy intended to treat adrenomyeloneuropathy.2 Notably, Syncona, the founding shareholder for both original companies, contributed $50 million to the newly combined company.
Notably, Spur announced its decision to prioritize the development of FLT201 in April 2023.3 At the time, it also announced that it would be deprioritizing development of FLT190, its gene therapy program for Fabry disease. The company also reduced its workforce by 30% in tandem with the move.
“While we remain encouraged by the data on FLT190 in Fabry disease, we have paused its development and are further streamlining the organization to extend our cash runway and focus on FLT201 in Gaucher disease,” Parini said in an April 2023 statement.3 “I want to extend my sincere gratitude to all of our colleagues for their dedication and their contributions to Freeline, as well as to the investigators and patients who have participated in and supported the development of FLT190.”
